Risk factor identification and contribution to surgery-specific surgical site infection

Risk factor identification and contribution to surgery-specific surgical site infection | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Research article Risk factor identification and contribution to surgery-specific surgical site infection (Magnus) Johan Magnus van Niekerk, Margreet C Vos, Alfred Stein, and 3 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.2.9189/v1 This work is licensed under a CC BY 4.0 License Status: Posted Version 1 posted You are reading this latest preprint version Abstract Background: To identify common risk factors for the future occurrence of SSI across digestive system surgical procedures, thoracic surgery and orthopaedic procedures and quantify what the marginal contribution of explaining the future occurrence of SSI is of risk factors specific to each group of surgeries. Methods: Retrospective data from serial point-prevalence studies, performed at the Erasmus MC University Medical Center, Rotterdam, The Netherlands were used, together with medical data, from 3.250 surgical procedures, during the period January 2013 to 29 June 2014. Common risk factors across three groups of surgical procedures were identified by scanning literature and univariate analysis. A multivariate forward-step logistic regression model was used to identify the marginal contribution of the risk factor specific to each group of surgical procedure using the increase in the Gini coefficient. Results: For digestive system surgical procedures, antibiotic use, temperature, smoking status, age, CRP, thrombocyte, during of surgery and surgical urgency are risk factors for SSI, where the last four were specific to the digestive system group of surgical procedures and increased the Gini coefficient by 9.5% (0.63 to 0.69). Preoperative length of stay, antibiotic use and Leukocyte are risk factors for orthopaedic surgical procedures. Temperature, age and the use of antibiotics were significant for thoracic surgical procedures. Conclusion: ASA class, body mass index (BMI), Preoperative length of stay, diabetes, antibiotic use, age, Leukocyte, temperature and smoking status as general risk factors common to digestive, orthopaedic and thoracic surgical procedures using existing literature and univariate logistic regression. Risk factors for SSI, specific to a surgical procedure group can increase the ability to explain the future occurrence of SSI by 9.5%. The models developed in this study can aid healthcare workers to improve preoperative counselling and help identify potentially modifiable risk factors. Internal Medicine Specialties Surgical Wound Infection Risk Factors Digestive System Surgical Procedures Thoracic Surgery Orthopaedic Procedures Background Surgical site infections (SSI), as defined by the European Centre for Disease Prevention and Control (ECDC) [1], make up 19.6% of the total number of healthcare-associated infections (HAIs) in Europe. With an estimated 81.089 patients in Europe having an HAI on any given day, almost 16.000 people in Europe are suffering from some form of SSI at any given time [2]. The burden of SSI can be measured in terms of increased length of stay in hospital, additional (surgical) procedures required, increased morbidity and mortality as well as in economic terms [3]. The use of surgical antimicrobial prophylaxis (SAP) has altered the outcome of surgery dramatically with early studies already showing odds of SSI being less than half after SAP was administered [4]. Risk factors relating to the patient, procedure and the environment also alter the odds of developing an SSI. Research has been done to identify risk factors for SSI with the hope that it will lead to pre-emptive action to reduce the incidence rate of SSI [5–11]. Patient related risk factors for SSI, such as obesity, diabetes, surgery duration and the American Society of Anaesthesiologists (ASA) score are risk factors for digestive system, thoracic and orthopaedic surgical procedures [15], [18–28]. Some risk factors are only relevant to certain types of surgical procedures, but the marginal contribution of these surgery specific risk factors to explain the occurrence of SSI has yet to be reported. The ECDC reports the SSI surveillance data in 10 national health safety network (NHSN) categories, which combines ICD-10-CM surgical procedure codes together [1]. The literature, concerning risk factors for SSI, is segmented by the same categories and is done for good reason. Segmentation makes it possible to find useful and relevant risk factors unique to each segment. For this study, we focus on digestive system, thoracic and orthopaedic surgical procedures. Digestive system surgical procedures are more prone to SSI and the severity vary. The occurrence of SSI after thoracic and orthopaedic surgeries are both relatively low, but the severity of an SSI after a thoracic is much higher compared to orthopaedic surgeries. It has yet to be shown which risk factors are common across these three different group of surgical procedures and what the benefit is of including risk factors unique to them. Risk factors common across three groups of surgeries are identified from existing literature and the marginal contribution of the risk factors unique to each of them when predicting SSI is quantified. Methods The Erasmus MC University Medical Center in Rotterdam, the Netherlands (Erasmus MC), is the largest university medical hospital in the Netherlands with more than 1.300 beds. [21] We used the verified output from the infection control practitioners (ICP) for the SSI output variable. Weekly (alter two-weekly) prevalence surveys were performed during January 2013 until June 2014 using a semi-automated algorithm [21,22]. In short, an algorithm was used to calculate a nosocomial infection index (NII) which was then verified by infection control practitioners (ICP) in case of a positive outcome to determine whenever HAI was present or not. All patients with a NII > 7 are verified by an ICP, and a definite outcome SSI was concluded by the ICP using the electronic patient data system. We included 3,250 surgical procedures, performed on 2,929 distinct patients. Data were extracted from a centralised database, containing cross-departmental data, and clinical synopsis reports, infectious disease consultation reports, laboratory results and imaging reports. Surgeries were included if they form part of the three types of surgeries under investigation in this study and had a point prevalence study within 30 days after the surgery took place. If the surgery took place within 30 days after an included surgery, then the latter surgery was excluded. The data used for this study were anonymized in accordance to the Dutch Personal Data Protection Act (WBP). Approval of the Medical Ethical Committee was obtained (MEC-2018-1185). There was no need to obtain informed consent because this is a fully anonymous retrospective study and no further interaction with the patients were necessary. Risk factors relating to digestive system surgical procedures, thoracic surgery and orthopaedic procedures were identified from existing literature using the corresponding medical subject headings (MeSH). For a risk factor to be included in this study, it had to be significant in the multivariate analysis of the literature considered. The risk factors which are common to all three groups of surgeries, according to our literature scan, are called “general risk factors”. Statistical analysis During the initial analysis of the data, a missing value analysis is performed. Using IBM SPSS Statistics for Windows, Version 25, we performed t-tests to determine if the differences in the averages of variables with missing values and those without were statistically significant. These tests, together with Little’s MCAR test, convinced us that the missing values were not completely randomly missing and that we could not make use of more simple imputation methods. We chose to use conditional Markov chain Monte Carlo (MCMC) with multiple imputations for the imputation process. [23,24] Tests for significant differences in the occurrence of SSI across all three groups of surgeries were performed using the Wilcoxon-Kruskal-Wallis test for continuous variables and Pearson chi-square test for categorical variables. In this study we consider variables to be statistically significant if the corresponding p-value is less than 0.05. In order to build a prognostic prediction model for SSI, Hosmer et al. suggests fitting a univariate logistic regression model to each variable separately and if the p-value is less than a certain p-value, 0.1 is this case, then consider the variable good enough to include in the multivariate logistic regression model. [26] The data were split according to the different groups of surgeries in order to evaluate them separately. A univariate analysis was performed for each of the three groups of surgeries using all the variables identified across the three different groups. Significant variables in the univariate analysis are then also added to the list of variables associated with each group of surgery, together with the variables identified from the literature. This results in an extended list of general risk factors as more risk factors are common across the three groups of surgeries. A multivariate logistic regression model was applied using a forward stepwise approach.(28) The multivariate model was first built using the general risk factors and then, using the result as a starting point, the surgery group specific risk factors were added to the model in order of the Akaike information criterion (AIC) until convergence is reached. In this case, we chose the conversion of the model to imply that there are no additional variables which can be added which will be statistically significant with a p-value of less than 0.05 or an AIC of 3.8415. Each variable contributes information about the SSI outcome variable, which in turn reduces the error or residual of the model. For a logistic regression model, the residual or error can be stated in terms of deviance. To determine the importance of the different variables in the final model, we calculate the difference in model deviance caused by the exclusion of each variable. Model performance are determined using the Gini coefficient after each step of the multivariate modelling process and the difference is reported as the marginal contribution of surgery group specific risk factors for this study. [27] Results In total, 55 risk factors were identified across the three types of surgical procedures from literature [15], [18–28]. Of the risk factors identified, ASA class, body mass index (BMI), Preoperative length of stay and diabetes were identified as general risk factors. The complete list of risk factors identified from literature can be found in Table 6 as part of the Appendix. There are 24 risk factors unique to digestive system surgical procedures, 14 to orthopaedic procedures and 15 to thoracic surgeries. Of the 55 risk factors identified from the literature, 23 could be extracted from our own data to use in this study. These 23 risk factors included in this study, together with the number of surgery groups they occurred in (N), are shown in Table 1. Table 1: Variables names and definitions used to investigate the future occurrence of SSI in this study Variable Abbreviation N Definition Demographic Gender GEN 2 Gender of patient Age AGE 2 Age of patient ASA class ASA 3 ASA class of patient BMI BMI 3 BMI of patient at the time of surgery. Behavioural Alcohol use ALC 2 Alcohol use of patient at the time of surgery. Smoking SMO 2 Smoking status of patient at the time of surgery. Comorbidities Heart disease HEA 2 Patient has a history of heart disease at the time of surgery. Liver disease LIV 2 Patient has a history of heart liver at the time of surgery. Hepatitis HEP 1 Hepatitis of patient at the time of surgery. Hyper tension HYP 1 Patient has a history of hyper tension. Diabetes DIA 3 Diabetes of patient at the time of surgery. Measurement Highest temperature TEM 1 Highest temperature of patient in the past 7 days before surgery. Highest CRP CRP 1 Highest CRP of patient in the past 7 days before surgery. Highest Leukocyte LEU 2 Highest Leukocyte of patient in the past 7 days before surgery. Highest protein PRO 1 Highest protein of patient in the past 7 days before surgery. Highest alkaline phosphatase ALK 1 Highest alkaline phosphatase of patient in the past 7 days before surgery. Highest glucose GLU 1 Highest glucose of patient in the past 7 days before surgery. Highest haemoglobin HEM 1 Highest haemoglobin of patient in the past 7 days before surgery. Highest thrombocyte THR 1 Highest thrombocyte of patient in the past 7 days before surgery. Operative Preoperative length of stay (days) LOS 3 Preoperative length of stay (days) of patient at the time of surgery. Antibiotic use ANT 1 Antibiotic use of patient at the time of surgery. Urgency URG 2 Urgency of the surgical procedure. Duration of surgery DUR 2 Duration of the surgical procedure. The test for differences for risk factors in Table 1 are shown in Table 2. The variables indicating the type of surgery was statistically significant but there was no significant difference between the ASA classes of patients for which SSI occurred. Diabetes and BMI were also not significant. Preoperative length of stay was the only general risk factor which was statistically significant. Antibiotics use, temperature and CRP were significant during initial analysis across the groups of surgeries with pvalue of less than 0.001. Table 2: Test for differences preoperative and operative characteristic for the occurrence of SSI Variable SSI = No (3.078) SSI = Yes (172) p-value Gender Female 1243 (95.2) 63 (4.8) 0.328 Male 1835 (94.4) 109 (5.6) Age 46.7 (26) 49 (23.5) 0.522 ASA class ASA CLASS I 426 (96.6) 15 (3.4) 0.124 ASA CLASS II 1043 (94.6) 60 (5.4) ASA CLASS III 1239 (94.8) 68 (5.2) ASA CLASS IV 356 (93.0) 27 (7.0) ASA CLASS V 14 (87.5) 2 (12.5) BMI 24.8 (5.1) 24.7 (4.7) 0.966 Alcohol use Current 1702 (95.0) 89 (5.0) 0.659 Never 1180 (94.3) 71 (5.7) Past 196 (94.2) 12 (5.8) Smoking Current 1396 (93.3) 101 (6.7) 0.002 Never 978 (95.7) 44 (4.3) Past 704 (96.3) 27 (3.7) Heart disease No 2942 (94.8) 161 (5.2) 0.225 Yes 136 (92.5) 11 (7.5) Liver disease No 2989 (94.7) 166 (5.3) 0.651 Yes 89 (93.7) 6 (6.3) Hepatitis No 3015 (94.6) 171 (5.4) 0.178 Yes 63 (98.4) 1 (1.6) Hyper tension No 2440 (94.5) 142 (5.5) 0.299 Yes 638 (95.5) 30 (4.5) Diabetes No 2807 (94.9) 151 (5.1) 0.129 Yes 271 (92.8) 21 (7.2) Highest temperature 38.1 (0.9) 38.9 (1) <0.001 Highest CRP 38.8 (69.3) 81.8 (105.2) <0.001 Highest Leukocyte 11.6 (6.7) 12.6 (7.1) 0.06 Highest protein 63.1 (10.4) 59.3 (11.8) <0.001 Highest alkaline phosphatase 110.3 (102.5) 123.3 (104.1) 0.04 Highest glucose 9.4 (3.3) 10.1 (3.5) 0.002 Highest haemoglobin 8.1 (1.2) 8 (1.3) 0.262 Highest thrombocyte 207.8 (103.7) 171.6 (92.9) <0.001 Preoperative length of stay (days) 6.4 (24.5) 10 (28.8) <0.001 Antibiotic use No 2051 (97.7) 49 (2.3) <0.001 Yes 1027 (89.3) 123 (10.7) Type of surgery Digestive System Surgical Procedures 1010 (90.5) 106 (9.5) <0.001 Orthopaedic Procedures 941 (97.1) 28 (2.9) Thoracic Surgery 1127 (96.7) 38 (3.3) Urgency Elective 1586 (96.4) 59 (3.6) <0.001 Emergency 1492 (93.0) 113 (7.0) Duration of surgery 245.1 (131.1) 274.4 (163.2) 0.125 The significant univariate results of digestive system, orthopaedic and thoracic surgical procedures are shown in Table 3 and the full results can be found in Table 5, Table 6 and Table 7 in the Appendix. Antibiotic use, age, Leukocyte, temperature and smoking status were added to the list of general risk factors after being found statistically significant in the univariate analysis – increasing the number of general risk factors to 9. BMI and diabetes were two risk factors identified as general Risk factors from the literature but were not found significant in any of the three univariate analyses in our own study. Table 3: Digestive system surgical procedures: univariate analysis of risk factors for the future occurrence of SSI Characteristic SSI = No (3.078) SSI = Yes (172) Univariate OR (95% CI, p-value) Digestive system surgical procedures Age 23 310 (30.7) 9 (8.5) 23 700 (69.3) 97 (91.5) 4.77 (2.51-10.28, p<0.001) ASA class ASA CLASS I 140 (13.9) 6 (5.7) ASA CLASS II 452 (44.8) 46 (43.4) 2.37 (1.07-6.31, p=0.052) ASA CLASS III 343 (34.0) 40 (37.7) 2.72 (1.21-7.28, p=0.026) ASA CLASS IV 75 (7.4) 14 (13.2) 4.36 (1.67-12.73, p=0.004) Smoking Current 492 (48.7) 67 (63.2) Never 337 (33.4) 20 (18.9) 0.44 (0.25-0.72, p=0.002) Past 181 (17.9) 19 (17.9) 0.77 (0.44-1.29, p=0.342) Highest temperature 38 647 (64.1) 28 (26.4) (38,39] 243 (24.1) 40 (37.7) 3.80 (2.31-6.36, p<0.001) 39 120 (11.9) 38 (35.8) 7.32 (4.34-12.47, p<0.001) Highest CRP 164 905 (89.6) 75 (70.8) 164 105 (10.4) 31 (29.2) 3.56 (2.22-5.63, p<0.001) Highest protein 57 321 (31.8) 53 (50.0) 57 689 (68.2) 53 (50.0) 0.47 (0.31-0.70, p<0.001) Highest glucose 8.2 494 (48.9) 31 (29.2) 8.2 516 (51.1) 75 (70.8) 2.32 (1.51-3.63, p<0.001) Highest thrombocyte 225 692 (68.5) 95 (89.6) 225 318 (31.5) 11 (10.4) 0.25 (0.13-0.46, p<0.001) Antibiotic use No 581 (57.5) 19 (17.9) Yes 429 (42.5) 87 (82.1) 6.20 (3.80-10.64, p<0.001) Urgency Elective 548 (54.3) 34 (32.1) Emergency 462 (45.7) 72 (67.9) 2.51 (1.65-3.89, p<0.001) Duration of surgery 530 971 (96.1) 89 (84.0) 530 39 (3.9) 17 (16.0) 4.76 (2.53-8.62, p<0.001) Orthopaedic surgical procedures Highest temperature 38 747 (79.4) 15 (53.6) 38 194 (20.6) 13 (46.4) 3.34 (1.54-7.14, p=0.002) Highest CRP 144 883 (93.8) 20 (71.4) 144 58 (6.2) 8 (28.6) 6.09 (2.44-13.96, p<0.001) Highest Leukocyte 17.3 820 (87.1) 17 (60.7) 17.3 121 (12.9) 11 (39.3) 4.39 (1.95-9.48, p<0.001) Preoperative length of stay (days) 7 853 (90.6) 16 (57.1) 7 88 (9.4) 12 (42.9) 7.27 (3.27-15.79, p<0.001) Antibiotic use No 720 (76.5) 11 (39.3) Yes 221 (23.5) 17 (60.7) 5.03 (2.35-11.23, p<0.001) Thoracic surgical procedure Age 17 246 (21.8) 17 (44.7) 17 881 (78.2) 21 (55.3) 0.34 (0.18-0.67, p=0.001) Smoking Current 525 (46.6) 22 (57.9) Never 316 (28.0) 13 (34.2) 0.98 (0.48-1.95, p=0.959) Past 286 (25.4) 3 (7.9) 0.25 (0.06-0.73, p=0.025) Highest temperature 37 316 (28.0) 2 (5.3) (37,38] 612 (54.3) 20 (52.6) 5.16 (1.50-32.47, p=0.027) 38 199 (17.7) 16 (42.1) 12.70 (3.56-80.90, p=0.001) Antibiotic use No 750 (66.5) 19 (50.0) Yes 377 (33.5) 19 (50.0) 1.99 (1.04-3.82, p=0.037) Urgency Elective 605 (53.7) 14 (36.8) Emergency 522 (46.3) 24 (63.2) 1.99 (1.03-3.98, p=0.044) The general risk factors which were significant for digestive system surgical procedures were antibiotic use, temperature, smoking status and age according to the multivariate analysis results shown in Table 4. The additional significant risk factors, indicated in bold, which were unique to the digestive system surgery group, were CRP, thrombocyte, duration of the surgery and if the surgery was an elective or not. In this case, the general risk factors reduced the residual deviance from 700.66 to 570.24. The risk factors identified to be unique to digestive system surgical procedures reduced the residual deviance from 570.24 to 531.05 and improved the Gini coefficient from 0.63 to 0.69. Important to know, the variables CRP and thrombocyte were the biggest contributors in the increase in model performance with both decreasing the residual deviance by almost 14. Pre-operative length of stay, antibiotic use and Leukocyte were significant general risk factor for the orthopaedic group of surgeries, resulting in a Gini coefficient of 0.6. Temperature, age and antibiotic use were significant general risk factors for the thoracic group of surgical procedures and produced a Gini coefficient of 0.51. Neither the orthopaedic nor the thoracic group of surgical procedures had any significant risk factors unique to the group of surgeries. Table 4: Multivariate analysis of risk factors for the future occurrence of SSI by group of surgeries (Risk factors in bold are the additional risk factors not part of the general risk factors) Surgery type & variable Coefficient Multivariate OR (95% CI) p-value Residual deviance Digestive System Surgical Procedures (Intercept) -4.560 0.010 (0.004 - 0.024) <0.001 700.660 Antibiotic use Yes 0.911 2.488 (1.355 - 4.797) 0.005 636.770 Highest temperature (38, 39] 0.962 2.616 (1.526 - 4.527) <0.001 588.810 Highest temperature 39 1.757 5.796 (3.226 - 10.517) <0.001 588.810 Smoking = Never -0.929 0.395 (0.218 - 0.688) <0.001 578.020 Smoking = Past -0.551 0.577 (0.308 - 1.040) 0.075 578.020 Age 23 1.122 3.071 (1.347 - 7.578) 0.010 570.240 Highest CRP 164 1.074 2.928 (1.681 - 5.038) <0.001 556.300 Highest thrombocyte 225 -0.983 0.374 (0.179 - 0.720) 0.005 542.650 Duration of surgery 530 1.221 3.390 (1.612 - 6.957) <0.001 535.180 Urgency Emergency 0.529 1.698 (1.018 - 2.883) 0.045 531.050 Orthopaedic Surgical Procedures (Intercept) -4.682 0.009 (0.004 - 0.017) <0.001 253.650 Preoperative length of stay7 1.552 4.721 (2.035 - 10.674) <0.001 232.920 Antibiotic use Yes 1.224 3.402 (1.521 - 7.839) 0.003 223.240 Highest Leukocyte 17.3 1.254 3.505 (1.511 - 7.819) 0.003 215.080 Thoracic Surgical Procedures (Intercept) -4.195 0.015 (0.002 - 0.053) <0.001 334.890 Highest temperature (37,38] 1.311 3.709 (1.055 - 23.515) 0.081 315.670 Highest temperate 38 1.826 6.209 (1.676 - 40.324) 0.018 315.670 Age 17 -1.742 0.175 (0.062 - 0.463) <0.001 311.810 Antibiotic use Yes 1.549 4.708 (1.846 - 13.172) 0.002 300.860 The resultant equations of the multivariate logistic regression models are provided in Equation 1 to Equation 3. The abbreviations of the variable names are provided in Table 1. We summarise the findings concerning the statistical significance of the risk factors by surgical procedure in Table 5. The stage of significance indicates the last stage of the analysis where this risk factor was statistically significant for corresponding group of surgeries. The source indicates where the reason why each risk factor was considered for each group of surgeries. In the last section we see the risk factors we found in literature but were not significant for any of the groups of surgeries for both the univariate and multivariate analysis. Risk factors which were significant in the multivariate analysis, but not the univariate analysis are shown in the first part of Table 5. Table 5: Statistical significance of risk factors and the source which lead them to be considered by surgical procedure Stage of significance (Source) Digestive System Orthopaedic Thoracic Multivariate Analysis ( Literature ) Age * Preoperative length of stay (days) * Duration of surgery * Highest temperature * Highest thrombocyte * Smoking * Urgency * Multivariate Analysis ( Univariate Analysis ) Antibiotic use * * * Age * Highest CRP * Highest Leukocyte * Highest temperature * Univariate Analysis ( Literature ) ASA class * Highest CRP * Highest glucose * Highest Leukocyte * Highest protein * Urgency * Univariate Analysis ( Univariate Analysis ) Highest temperature * Smoking * None ( Literature ) Age * ASA class * * BMI * * * Preoperative length of stay (days) * * Diabetes * * * Alcohol use * * Duration of surgery * Gender * * Heart disease * * Hepatitis * Highest alkaline phosphatase * Highest haemoglobin * Highest Leukocyte * Hyper tension * Liver disease * * Smoking * Discussion We aimed to identify general risk factors, common across three groups of surgeries, using literature and univariate analysis to quantify the marginal contribution of the risk factors not common to those three groups of surgeries. From the literature we could identify ASA class, BMI, preoperative length of stay (days) and diabetes as general risk factors. We added antibiotic use, age, Leukocyte, temperature and smoking status as to the list of general risk factors by using the results of the univariate analysis. These risk factors might have been overlooked should this study have focussed on only one type of surgery. Using this process, researchers may find useful risk factors to explain the future occurrence of SSI in their own environment, but not generally reported by literature of the specific type of surgery under investigation. This study produced three prognostic prediction models (Equation 1 – 3) for the future occurrence of SSI within a 30 days period after undergoing one of the three group of surgical procedures. Using existing literature and the results of the univariate analysis, we identified general risk factors across three groups of surgical procedures and showed that the marginal contribution for models predicting SSI could be up to 9.5% in terms of discriminatory power by including surgery group specific risk factors. We also showed that this benefit can be measured in terms of reduced model error and ability to discriminate using the Gini as performance measure. The initial results of the missing data analysis revealed that the variables relating to the CRP and Leukocyte levels have a sizeable amount of missing values. The difference in the preoperative length of stay led us to believe that most of these missing values were caused by patients who did not stay sufficiently long in the hospital to have the laboratory tests before the surgical procedure took place. A possible explanation could be that most of the missing values were due to short-stay elective or emergence surgery patients or the absence of signs of infections which would lead to not requesting this chemical test. These laboratory tests are usually only done in case the patient is suspected of already having an infection. Our conclusion was that final model might be prone to overestimate the probability of SSI since the missing values were imputed using data from patients with greater risk of infection. We used a 30-day outcome period in which we observe if an SSI was present or not, but according the CDC definition, this outcome period should be 1 year for surgical implantation procedures. Since our data only spans over 18 months, it was not possible to use a 12-month outcome windows for all surgical implantation procedures, which is a limitation of this study. Another limitation is that for all three groups of surgical procedures, the use of antibiotics is predictive of occurrence of SSI. This could mean that the patient is already fighting off some kind infection and is receiving treatment for a present condition which has nothing to do with the surgery under investigation. This study was performed in as a single centre study, which limits the generalisability of this study. Future research can repeat this research on multiple patient populations in order produce more generalisable results. The predictive models were designed with the aim to use it to investigate more variables as potential risk factors for the future occurrence of SSI, 30 days after a surgical procedure. The administration of prophylaxis and the optimal timing thereof is an important risk factor however, these data were not available, but in future we recommend that these data should also be included in similar studies. Although some research has been done in this regard, to our knowledge, it has not been done for this patient population and confounders identified in this study. The length of stay before a surgical procedure had mixed outcomes as a risk factor in the literature. Abuzaid et al. found it to be not significantly associated with SSI after isolated coronary artery bypass grafting, while Sang et al. found it to be highly significant [5,7]. Preoperative length of stay can also be a proxy for the severity of a patient’s condition, if we assume that patients in worse conditions are more likely to have been in hospital for a longer period before undergoing a surgical procedure. This variable was significant in both the univariate and multivariate case for the orthopaedic surgeries group. The cause of the increased lengths of stay could be investigated as a potential modifiable risk factor. Another opportunity for future research is to investigate which risk factors are predictive for the occurrence of SSI over different time periods. Doing this will enable healthcare workers to identify which risk factors explain the occurrence of SSI soon after surgery and which are better explain the occurrence of SSI nearing the end of the 30-day period or even later for implantation surgeries. This can help set guidelines to determine the vigilance necessary to mitigate the risk of SSI on a patient level. Conclusion We identified ASA class, body mass index (BMI), Preoperative length of stay, diabetes, antibiotic use, age, Leukocyte, temperature and smoking status as general risk factors common to digestive, orthopaedic and thoracic surgical procedures using existing literature and univariate logistic regression. We used a systematic approach to quantify the marginal contribution of the surgical procedure group specific risk factors using the results of a serial prevalence study and retrospective medical data. For digestive system surgical procedures, it is possible to increase the predictive power to explain the future occurrence of SSI by 9.5% by including CRP, thrombocyte, duration of the surgery and if the surgery will be elective or not. Pre-operative length of stay, antibiotic use and Leukocyte were significant general risk factor for the orthopaedic group of surgeries. Temperature, age and antibiotic use were significant general risk factors for the thoracic group of surgical procedures. Neither the orthopaedic nor the thoracic group of surgical procedures predictive risk factors unique to the group of surgeries. This is important because these results can help healthcare workers provided better preoperative counselling and aid researchers in identifying potentially modifiable risk factors in future research. List of abbreviations AIC Akaike information criterion ASA American society of anaesthesiologists ATC Anatomical therapeutic chemical AUC Area under the curve BSI Bloodstream infection CDC Centers for disease control and prevention CRP C-reactive protein ECDC European centre for disease prevention and control HAI Healthcare associated infection ICP Infection control practitioner LRTI Lower respiratory tract infection MCAR Missing completely at random MCMC Markov chain Monte Carlo MEC Medical ethical committee MeSH Medical subject headings NHSN National health safety network NII Nosocomial infection index ROC Receiver operator characteristic SAP Surgical antimicrobial prophylaxis SSI Surgical site infections SSI Surgical site infections UTI Urinary tract infection WBP Dutch personal data protection act Declarations Ethics approval and consent to participate Approval from Medical Ethical Committee of Erasmus MC (MEC-2018-1185) Consent for publication All authors read and approved the manuscript. Availability of data and material The data that support the findings of this study are available from Erasmus MC but restrictions apply to the availability of these data, which were used under license for the current study, and so are not publicly available. Data are however available from the authors upon reasonable request and with permission of Erasmus MC. Competing interests None Funding The research was funded by Interreg VA, EurHealth-1Health project ( http://www.eurhealth-1health.eu/ ). Author’s contributions JM, JEWC, A and MC contributed to the conceptualization of the research and commenting on the draft and final version of the paper. MC contributed as the main medical expert and provided guidance on all medical aspects of this study, including sourcing and understanding the data. MC, LMA, AF contributed in editing and writing the draft and final version of the paper. JM performed the data analysis, statistical analysis and wrote the draft and final version of the paper. Acknowledgements We would like to thank C. P. (Conrad) van der Hoeven, A.G.D (Arnim) Mulder and M. (Marius) Vogel for their help and constant willingness to help with questions regarding the data used for this study. Also, thanks to R. H. (Roel) Streefkerk for the work done to organise and combine the data as well as producing the SSI outcome variable used in this study. References 1. European Centre for Disease Prevention and Control. Surveillance of surgical site infections in European hospitals – HAISSI protocol [Internet]. 2012. 1-47 p. Available from: http://www.ecdc.europa.eu/en/publications/Publications/120215_TED_SSI_protocol.pdf 2. Zarb P, Coignard B, Griskeviciene J, Muller A, Vankerckhoven V, Weist K, et al. point prevalence survey of healthcare-associated infections and antimicrobial use in European acute care hospitals. Vol. 17, Eurosurveillance. 2012. 1-16 p. 3. Jenks PJ, Laurent M, McQuarry S, Watkins R. Clinical and economic burden of surgical site infection (SSI) and predicted financial consequences of elimination of SSI from an English hospital. J Hosp Infect. 2014;86(1):24–33. 4. Westerman EL. Antibiotic prophylaxis in surgery: Historical background, rationa1e, and relationship to prospective payment. Am J Infect Control. 1984;12(6):339–43. 5. Leung S, Sang W, Chaturvedi R, Alam A, Samoukovic G, Varennes B De. Preoperative hospital length of stay as a modifiable risk factor for mediastinitis after cardiac surgery. J Cardiothorac Surg [Internet]. 2013;8(1):45. Available from: Journal of Cardiothoracic Surgery 6. Triantafyllopoulos G, Stundner O, Memtsoudis S, Poultsides LA. Patient, Surgery, and Hospital Related Risk Factors for Surgical Site Infections following Total Hip Arthroplasty. Sci World J. 2015;2015:1–9. 7. Abuzaid A, Zaki M, Al Tarief H. Potential risk factors for surgical site infection after isolated coronary artery bypass grafting in a Bahrain Cardiac Centre: A retrospective, case-controlled study. Hear Views. 2015;16(3):79. 8. Schimmel JJP, Horsting PP, de Kleuver M, Wonders G, van Limbeek J. Risk factors for deep surgical site infections after spinal fusion. Eur Spine J. 2010;19(10):1711–9. 9. Guohua X, cheng keping, Li J, Kong Q, Wang C, Nanyuan Y. Risk factors for surgical site infection in a teaching hospital: a prospective study of 1,138 patients. Patient Prefer Adherence. 2015;9:1171. 10. Gomila A, Carratalà J, Biondo S, Badia JM, Fraccalvieri D, Shaw E, et al. Predictive factors for early- and late-onset surgical site infections in patients undergoing elective colorectal surgery. A multicentre, prospective, cohort study. J Hosp Infect. 2018;99(1):24–30. 11. Martin ET, Kaye KS, Knott C, Nguyen H, Santarossa M, Evans R, et al. Diabetes and Risk of Surgical Site Infection: A Systematic Review and Meta-analysis. Infect Control Hosp Epidemiol. 2016;37(01):88–99. 12. Takahashi Y, Takesue Y, Fujiwara M, Tatsumi S, Ichiki K, Fujimoto J, et al. Risk factors for surgical site infection after major hepatobiliary and pancreatic surgery. J Infect Chemother [Internet]. 2018;24(9):739–43. Available from: https://doi.org/10.1016/j.jiac.2018.05.007 13. Silvestri M, Dobrinja C, Scomersi S, Giudici F, Turoldo A, Princic E, et al. Modifiable and non-modifiable risk factors for surgical site infection after colorectal surgery: a single-center experience. Surg Today. 2018;48(3):338–45. 14. Fukuda H. Patient-related risk factors for surgical site infection following eight types of gastrointestinal surgery. J Hosp Infect [Internet]. 2016;93(4):347–54. Available from: http://dx.doi.org/10.1016/j.jhin.2016.04.005 15. Kokudo T, Uldry E, Demartines N, Halkic N. Risk factors for incisional and organ space surgical site infections after liver resection are different. World J Surg. 2015;39(5):1185–92. 16. Isik O, Kaya E, Dundar HZ, Sarkut P. Surgical Site Infection: Re-assessment of the Risk Factors. Chirurgia (Bucur) [Internet]. 2015;110(5):457–61. Available from: http://www.ncbi.nlm.nih.gov/pubmed/26531790 17. Moreno Elola-Olaso A, Davenport DL, Hundley JC, Daily MF, Gedaly R. Predictors of surgical site infection after liver resection: A multicentre analysis using National Surgical Quality Improvement Program data. Hpb. 2012;14(2):136–41. 18. Lola I, Levidiotou S, Petrou A, Arnaoutoglou H, Apostolakis E, Papadopoulos GS. Are there independent predisposing factors for postoperative infections following open heart surgery? J Cardiothorac Surg [Internet]. 2011;6(1):151. Available from: http://cardiothoracicsurgery.biomedcentral.com/articles/10.1186/1749-8090-6-151 19. Chen LF, Arduino JM, Sheng S, Muhlbaier LH, Kanafani ZA, Harris AD, et al. Epidemiology and outcome of major postoperative infections following cardiac surgery: Risk factors and impact of pathogen type. Am J Infect Control. 2012;40(10):963–8. 20. Jolivet S, Lescure FX, Armand-Lefevre L, Raffoul R, Dilly MP, Ghodbane W, et al. Surgical site infection with extended-spectrum β-lactamase-producing Enterobacteriaceae after cardiac surgery: incidence and risk factors. Clin Microbiol Infect [Internet]. 2018;24(3):289–94. Available from: https://doi.org/10.1016/j.cmi.2017.07.004 21. Streefkerk RHRA, Moorman PW, Parlevliet GA, van der Hoeven C, Verbrugh HA, Vos MC, et al. An Automated Algorithm to Preselect Patients to Be Assessed Individually in Point Prevalence Surveys for Hospital-Acquired Infections in Surgery. Infect Control Hosp Epidemiol [Internet]. 2014;35(7):886–7. Available from: http://www.jstor.org/stable/info/10.1086/676868 22. Streefkerk RHRA, Borsboom GJJM, van der Hoeven CP, Vos MC, Verkooijen RP, Verbrugh HA. Evaluation of an Algorithm for Electronic Surveillance of Hospital-Acquired Infections Yielding Serial Weekly Point Prevalence Scores. Infect Control Hosp Epidemiol [Internet]. 2014 [cited 2017 Jul 18];35(07):888–90. Available from: https://www.cambridge.org/core/product/identifier/S0899823X00192372/type/journal_article 23. Asendorpf JB, Van De Schoot R, Denissen JJA, Hutteman R. Reducing bias due to systematic attrition in longitudinal studies: The benefits of multiple imputation. Int J Behav Dev. 2014;38(5):453–60. 24. Buuren S Van. Multiple imputation of discrete and continuous. Stat Methods Med Res. 2007;16(3):219–42. 25. Fayyad UM, Irani KB. Multi-Interval Discretization of Continuos-Valued Attributes for Classification Learning. Proc Int Jt Conf Uncertain AI. 1993;1022–7. 26. Hosmer DW, Lemeshow S. Applied logistic regression [Internet]. Wiley. 2000. 118-128 p. Available from: http://onlinelibrary.wiley.com/book/10.1002/9781118548387 27. Hanley JA, McNeil BJ. The meaning and use of the area under a receiver operating characteristic (ROC) curve. Radiology. 2014;143(1):29–36. 28. In Lee K, Koval JJ. Determination of the best significance level in forward stepwise logistic regression. Commun Stat - Simul Comput. 2007;26(2):559–75. 29. Liu J, Li N, Hao J, Li Y, Liu A, Wu Y, et al. Impact of the antibiotic stewardship program on prevention and control of surgical site infection during peri-operative clean surgery. Surg Infect (Larchmt). 2018;19(3):326–33. Appendix Table 6: Variables identified from literature and present in the data sample by group of surgeries Risk Factor Found in data Digestive System Orthopaedic Thoracic Total ASA class 1 1 1 1 3 BMI 1 1 1 1 3 Preoperative length of stay (days) 1 1 1 1 3 Diabetes 1 1 1 1 3 Age 1 1 1 2 Alcohol use 1 1 1 2 Duration of surgery 1 1 1 2 Gender 1 1 1 2 Heart disease 1 1 1 2 Highest Leukocyte 1 1 1 2 Liver disease 1 1 1 2 Smoking 1 1 1 2 Urgency 1 1 1 2 Hepatitis 1 1 1 Highest alkaline phosphatase 1 1 1 Highest CRP 1 1 1 Highest glucose 1 1 1 Highest haemoglobin 1 1 1 Highest protein 1 1 1 Highest temperature 1 1 1 Highest thrombocyte 1 1 1 Hyper tension 1 1 1 Immunosuppression 1 1 2 Anaesthesia 1 1 Antibiotic treatment in the previous 3 months 1 1 Bypass time 1 1 CDC Surgical wound classification (SWC) 1 1 Cerebrovascular accident 1 1 Chronic lung disease 1 1 Dialysis 1 1 Estimated blood loss (EBL) > 600ml 1 1 History of previous SSI 1 1 HIV 1 1 Hospitalization in the previous year 1 1 ICU admission during the preceding 6 months 1 1 Incision cleanness 2–4 1 1 Intraoperative hypothermia 1 1 Open fracture 1 1 Peripheral vascular disease 1 1 Postoperative ICU stay (days) 1 1 Preoperative open wound/infection 1 1 Previous coronary artery bypass graft surgery 1 1 Previous surgery 1 1 Prior operation on same joint 1 1 Re-admission to the CVICU 1 1 Revision or primary surgery 1 1 Spinal level of surgery 1 1 Surgery involving the sacrum or pelvis 1 1 Type of surgery procedure 1 1 Use of antibiotic prophylaxis 1 1 Table 7: Digestive system univariate analysis preoperative and operative characteristic for the future occurrence of SSI Characteristic SSI = Yes SSI = No Univariate OR (95%CI, p-value) Gender Female 433 (42.9) 40 (37.7) Male 577 (57.1) 66 (62.3) 1.24 (0.82-1.88, p=0.309) Age 23 310 (30.7) 9 (8.5) 23 700 (69.3) 97 (91.5) 4.77 (2.51-10.28, p<0.001) ASA class ASA CLASS I 140 (13.9) 6 (5.7) ASA CLASS II 452 (44.8) 46 (43.4) 2.37 (1.07-6.31, p=0.052) ASA CLASS III 343 (34.0) 40 (37.7) 2.72 (1.21-7.28, p=0.026) ASA CLASS IV 75 (7.4) 14 (13.2) 4.36 (1.67-12.73, p=0.004) BMI 23.7 (5) 24.2 (4.4) 1.02 (0.98-1.06, p=0.286) Alcohol use Current 473 (46.8) 47 (44.3) Never 457 (45.2) 51 (48.1) 1.12 (0.74-1.71, p=0.585) Past 80 (7.9) 8 (7.5) 1.01 (0.43-2.10, p=0.987) Smoking Current 492 (48.7) 67 (63.2) Never 337 (33.4) 20 (18.9) 0.44 (0.25-0.72, p=0.002) Past 181 (17.9) 19 (17.9) 0.77 (0.44-1.29, p=0.342) Heart disease No 960 (95.0) 97 (91.5) Yes 50 (5.0) 9 (8.5) 1.78 (0.80-3.57, p=0.126) Liver disease No 967 (95.7) 101 (95.3) Yes 43 (4.3) 5 (4.7) 1.11 (0.38-2.63, p=0.825) Hepatitis No 980 (97.0) 105 (99.1) Yes 30 (3.0) 1 (0.9) 0.31 (0.02-1.47, p=0.253) Hyper tension No 841 (83.3) 90 (84.9) Yes 169 (16.7) 16 (15.1) 0.88 (0.49-1.50, p=0.666) Diabetes No 931 (92.2) 93 (87.7) Yes 79 (7.8) 13 (12.3) 1.65 (0.85-2.98, p=0.117) Highest temperature 38 647 (64.1) 28 (26.4) (38,39] 243 (24.1) 40 (37.7) 3.80 (2.31-6.36, p<0.001) 39 120 (11.9) 38 (35.8) 7.32 (4.34-12.47, p<0.001) Highest CRP 164 905 (89.6) 75 (70.8) 164 105 (10.4) 31 (29.2) 3.56 (2.22-5.63, p<0.001) Highest Leukocyte 12.2 (7.4) 12.2 (7.6) 1.00 (0.97-1.03, p=0.992) Highest protein 57 321 (31.8) 53 (50.0) 57 689 (68.2) 53 (50.0) 0.47 (0.31-0.70, p<0.001) Highest Leukocyte 149.8 (128.7) 138.2 (108.6) 1.00 (1.00-1.00, p=0.372) Highest glucose 8.2 494 (48.9) 31 (29.2) 8.2 516 (51.1) 75 (70.8) 2.32 (1.51-3.63, p<0.001) Highest haemoglobin 7.9 (1.3) 7.9 (1.2) 1.02 (0.88-1.19, p=0.758) Highest thrombocyte 225 692 (68.5) 95 (89.6) 225 318 (31.5) 11 (10.4) 0.25 (0.13-0.46, p<0.001) Preoperative length of stay (days) 7.2 (26.1) 10.1 (32.8) 1.00 (1.00-1.01, p=0.286) Antibiotic use No 581 (57.5) 19 (17.9) Yes 429 (42.5) 87 (82.1) 6.20 (3.80-10.64, p<0.001) Urgency Elective 548 (54.3) 34 (32.1) Emergency 462 (45.7) 72 (67.9) 2.51 (1.65-3.89, p<0.001) Duration of surgery 530 971 (96.1) 89 (84.0) 530 39 (3.9) 17 (16.0) 4.76 (2.53-8.62, p<0.001) Table 8: Orthopaedic surgical procedures univariate analysis preoperative and operative characteristic for the future occurrence of SSI Characteristic SSI = Yes SSI = No Univariate OR (95%CI, p-value) Gender Female 404 (42.9) 10 (35.7) Male 537 (57.1) 18 (64.3) 1.35 (0.63-3.08, p=0.448) Age 49 (21.4) 48.4 (18) 1.00 (0.98-1.02, p=0.880) ASA class ASA CLASS I 254 (27.0) 9 (32.1) ASA CLASS II 411 (43.7) 9 (32.1) 0.62 (0.24-1.60, p=0.314) ASA CLASS III 247 (26.2) 8 (28.6) 0.91 (0.34-2.43, p=0.856) ASA CLASS IV 29 (3.1) 2 (7.1) 1.95 (0.29-8.02, p=0.409) BMI 25.8 (5) 27.2 (4.6) 1.06 (0.98-1.13, p=0.140) Alcohol use Current 486 (51.6) 16 (57.1) Never or Past 455 (48.4) 12 (42.9) 0.80 (0.37-1.70, p=0.567) Smoking Current 379 (40.3) 12 (42.9) Never 325 (34.5) 11 (39.3) 1.07 (0.46-2.47, p=0.875) Past 237 (25.2) 5 (17.9) 0.67 (0.21-1.82, p=0.451) Heart disease No 889 (94.5) 26 (92.9) Yes 52 (5.5) 2 (7.1) 1.32 (0.21-4.57, p=0.714) Liver disease No 914 (97.1) 27 (96.4) Yes 27 (2.9) 1 (3.6) 1.25 (0.07-6.24, p=0.827) Hyper tension No 781 (83.0) 23 (82.1) Yes 160 (17.0) 5 (17.9) 1.06 (0.35-2.62, p=0.906) Diabetes No 864 (91.8) 25 (89.3) Yes 77 (8.2) 3 (10.7) 1.35 (0.32-3.95, p=0.633) Highest temperature 38 747 (79.4) 15 (53.6) 38 194 (20.6) 13 (46.4) 3.34 (1.54-7.14, p=0.002) Highest CRP 144 883 (93.8) 20 (71.4) 144 58 (6.2) 8 (28.6) 6.09 (2.44-13.96, p<0.001) Highest Leukocyte 17.3 820 (87.1) 17 (60.7) 17.3 121 (12.9) 11 (39.3) 4.39 (1.95-9.48, p<0.001) Highest protein 62.2 (10.4) 59.5 (11) 0.98 (0.94-1.01, p=0.181) Highest alkaline phosphatase 89.8 (72.3) 79.6 (40.9) 1.00 (0.99-1.00, p=0.455) Highest glucose 8.6 (3) 9.2 (4) 1.06 (0.94-1.17, p=0.282) Highest haemoglobin 8.1 (1.2) 7.9 (1.3) 0.90 (0.65-1.24, p=0.510) Highest thrombocyte 185 (94.2) 157.8 (90.2) 1.00 (0.99-1.00, p=0.134) Preoperative length of stay (days) 7 853 (90.6) 16 (57.1) 7 88 (9.4) 12 (42.9) 7.27 (3.27-15.79, p<0.001) Antibiotic use No 720 (76.5) 11 (39.3) Yes 221 (23.5) 17 (60.7) 5.03 (2.35-11.23, p<0.001) Urgency Elective 433 (46.0) 11 (39.3) Emergency 508 (54.0) 17 (60.7) 1.32 (0.62-2.93, p=0.483) Duration of surgery 205.4 (111.2) 199.6 (108.6) 1.00 (1.00-1.00, p=0.788) Table 9: Thoracic surgical procedures univariate analysis preoperative and operative characteristic for the future occurrence of SSI Characteristic SSI = Yes SSI = No Univariate OR (95%CI, p-value) Gender Female 406 (36.0) 13 (34.2) Male 721 (64.0) 25 (65.8) 1.08 (0.56-2.20, p=0.819) Age 17 246 (21.8) 17 (44.7) 17 881 (78.2) 21 (55.3) 0.34 (0.18-0.67, p=0.001) ASA class ASA CLASS II 212 (18.8) 5 (13.2) ASA CLASS III 649 (57.6) 20 (52.6) 1.31 (0.52-3.96, p=0.597) ASA CLASS IV 266 (23.6) 13 (34.2) 2.07 (0.77-6.54, p=0.173) BMI 24.9 (5.1) 24.1 (4.8) 0.97 (0.91-1.03, p=0.323) Alcohol use Current 743 (65.9) 26 (68.4) Never 333 (29.5) 8 (21.1) 0.69 (0.29-1.47, p=0.359) Past 51 (4.5) 4 (10.5) 2.24 (0.64-6.03, p=0.147) Smoking Current 525 (46.6) 22 (57.9) Never 316 (28.0) 13 (34.2) 0.98 (0.48-1.95, p=0.959) Past 286 (25.4) 3 (7.9) 0.25 (0.06-0.73, p=0.025) Hyper tension No 818 (72.6) 29 (76.3) Yes 309 (27.4) 9 (23.7) 0.82 (0.36-1.69, p=0.612) Diabetes No 1012 (89.8) 33 (86.8) Yes 115 (10.2) 5 (13.2) 1.33 (0.45-3.20, p=0.557) Highest temperature 37 316 (28.0) 2 (5.3) (37,38] 612 (54.3) 20 (52.6) 5.16 (1.50-32.47, p=0.027) 38 199 (17.7) 16 (42.1) 12.70 (3.56-80.90, p=0.001) Highest CRP 30.5 (60) 40.6 (61.6) 1.00 (1.00-1.01, p=0.313) Highest Leukocyte 11.2 (6.6) 12 (6.2) 1.02 (0.97-1.06, p=0.470) Highest protein 65.6 (9.5) 65.4 (9.7) 1.00 (0.97-1.03, p=0.865) Highest alkaline phosphatase 92.1 (86.1) 114.1 (114.7) 1.00 (1.00-1.00, p=0.134) Highest glucose 10.3 (3.2) 10.5 (2.8) 1.02 (0.92-1.12, p=0.684) Highest haemoglobin 8.3 (1.1) 8.2 (1.4) 0.97 (0.72-1.28, p=0.814) Highest thrombocyte 243.3 (102.5) 233 (110.8) 1.00 (1.00-1.00, p=0.545) Preoperative length of stay (days) 6.4 (21.9) 5.5 (11.1) 1.00 (0.97-1.01, p=0.806) Antibiotic use No 750 (66.5) 19 (50.0) Yes 377 (33.5) 19 (50.0) 1.99 (1.04-3.82, p=0.037) Urgency Elective 605 (53.7) 14 (36.8) Emergency 522 (46.3) 24 (63.2) 1.99 (1.03-3.98, p=0.044) Duration of surgery 291.6 (126.7) 270.1 (156.2) 1.00 (1.00-1.00, p=0.307) Cite Share Download PDF Status: Posted Version 1 posted You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. 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Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {"props":{"pageProps":{"initialData":{"identity":"rs-619","acceptedTermsAndConditions":true,"allowDirectSubmit":true,"archivedVersions":[],"articleType":"Research article","associatedPublications":[],"authors":[{"id":82807,"identity":"cbf05fc7-780c-4a1e-b651-55418c474c50","order_by":1,"name":"(Magnus) Johan Magnus van Niekerk","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAA/klEQVRIiWNgGAWjYBACxgYogw0IGRgO2CCk+IjUksbAA+IdAIsQBGAthwlrYW7gTmDmqbmTx8felvi44sz5xP0Syccef6hgyMOlhbGBdwMzz7FnxWw8xw4bnrlxO7FHIi3d4MAZhmJ8WhhnsB1ObJNIb5Ns+ADUIp1jJnGwjSGxDa+Wf0At8s/bfzZ8OAfUkv9N4uA//FoYPraBbGE7xthw4wDIFjaJgw14tDTzbjjwsQ+ohSctWbLhTLJxz/1nZhJnjkng1GLY3rvxQcK3w4nz248Zfmw4Zifb3nP4mURFjU1iPy4tzZBIwAASODQwMMjjlBkFo2AUjIJRAAMA56tgN7Wl9ikAAAAASUVORK5CYII=","orcid":"https://orcid.org/0000-0002-4737-5809","institution":"Universiteit Twente","correspondingAuthor":true,"submittingAuthor":false,"prefix":"","firstName":"(Magnus)","middleName":"Johan Magnus van","lastName":"Niekerk","suffix":""},{"id":82808,"identity":"3989ae3b-ed84-4920-a053-885415411a16","order_by":2,"name":"Margreet C Vos","email":"","orcid":"","institution":"Erasmus MC","correspondingAuthor":false,"submittingAuthor":false,"prefix":"","firstName":"Margreet","middleName":"C","lastName":"Vos","suffix":""},{"id":82809,"identity":"f8d80edd-7228-49c1-8bd7-5ceb8a740ab8","order_by":3,"name":"Alfred Stein","email":"","orcid":"","institution":"Universiteit Twente Faculteit Geo-Informatie Wetenschappen en Aardobservatie","correspondingAuthor":false,"submittingAuthor":false,"prefix":"","firstName":"Alfred","middleName":"","lastName":"Stein","suffix":""},{"id":82810,"identity":"656ee169-00c9-49e5-b349-0d6a2211519e","order_by":4,"name":"(Annemarie) M A Braakman-Jansen","email":"","orcid":"","institution":"Universiteit Twente","correspondingAuthor":false,"submittingAuthor":false,"prefix":"","firstName":"(Annemarie)","middleName":"M A","lastName":"Braakman-Jansen","suffix":""},{"id":82811,"identity":"e13b7225-3ddc-44b4-8b78-920f6563e965","order_by":5,"name":"Anne F Voor in´t holt","email":"","orcid":"","institution":"Erasmus MC","correspondingAuthor":false,"submittingAuthor":false,"prefix":"","firstName":"Anne","middleName":"F Voor in´t","lastName":"holt","suffix":""},{"id":82812,"identity":"63b6118a-9680-4086-b013-5580b02b117a","order_by":6,"name":"(Lisette) Julia Elisabeth Wilhelmina Cornelia van Gemert-Pijnen","email":"","orcid":"","institution":"Universiteit Twente","correspondingAuthor":false,"submittingAuthor":false,"prefix":"","firstName":"(Lisette)","middleName":"Julia Elisabeth Wilhelmina Cornelia van","lastName":"Gemert-Pijnen","suffix":""}],"badges":[],"createdAt":"2019-04-15 13:27:45","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.2.9189/v1","doiUrl":"https://doi.org/10.21203/rs.2.9189/v1","draftVersion":[],"editorialEvents":[],"editorialNote":"","failedWorkflow":false,"files":[{"id":13466612,"identity":"357a7dda-07af-4423-8360-bcc171bf3766","added_by":"auto","created_at":"2021-09-16 20:51:37","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":402666,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-619/v1/5f3ad0df-13d3-494c-b7e5-24d5b4d2cb6b.pdf"}],"financialInterests":"","formattedTitle":"Risk factor identification and contribution to surgery-specific surgical site infection","fulltext":[{"header":"Background","content":"\u003cp\u003eSurgical site infections (SSI), as defined by the European Centre for Disease Prevention and Control (ECDC) [1], make up 19.6% of the total number of healthcare-associated infections (HAIs) in Europe. With an estimated 81.089 patients in Europe having an HAI on any given day, almost 16.000 people in Europe are suffering from some form of SSI at any given time [2]. The burden of SSI can be measured in terms of increased length of stay in hospital, additional (surgical) procedures required, increased morbidity and mortality as well as in economic terms [3]. \u003c/p\u003e\n\u003cp\u003eThe use of surgical antimicrobial prophylaxis (SAP) has altered the outcome of surgery dramatically with early studies already showing odds of SSI being less than half after SAP was administered [4]. Risk factors relating to the patient, procedure and the environment also alter the odds of developing an SSI. Research has been done to identify risk factors for SSI with the hope that it will lead to pre-emptive action to reduce the incidence rate of SSI [5–11].\u003c/p\u003e\n\u003cp\u003ePatient related risk factors for SSI, such as obesity, diabetes, surgery duration and the American Society of Anaesthesiologists (ASA) score are risk factors for digestive system, thoracic and orthopaedic surgical procedures [15], [18–28]. Some risk factors are only relevant to certain types of surgical procedures, but the marginal contribution of these surgery specific risk factors to explain the occurrence of SSI has yet to be reported.\u003c/p\u003e\n\u003cp\u003eThe ECDC reports the SSI surveillance data in 10 national health safety network (NHSN) categories, which combines ICD-10-CM surgical procedure codes together [1]. The literature, concerning risk factors for SSI, is segmented by the same categories and is done for good reason. Segmentation makes it possible to find useful and relevant risk factors unique to each segment. For this study, we focus on digestive system, thoracic and orthopaedic surgical procedures. Digestive system surgical procedures are more prone to SSI and the severity vary. The occurrence of SSI after thoracic and orthopaedic surgeries are both relatively low, but the severity of an SSI after a thoracic is much higher compared to orthopaedic surgeries. It has yet to be shown which risk factors are common across these three different group of surgical procedures and what the benefit is of including risk factors unique to them.\u003c/p\u003e\n\u003cp\u003eRisk factors common across three groups of surgeries are identified from existing literature and the marginal contribution of the risk factors unique to each of them when predicting SSI is quantified.\u003c/p\u003e"},{"header":"Methods","content":"\u003cp\u003e\u003ca name=\"_Hlk526962242\"/\u003eThe Erasmus MC University Medical Center in Rotterdam, the Netherlands (Erasmus MC), is the largest university medical hospital in the Netherlands with more than 1.300 beds. [21]\u003c/p\u003e\n\u003cp\u003eWe used the verified output from the infection control practitioners (ICP) for the SSI output variable. Weekly (alter two-weekly) prevalence surveys were performed during January 2013 until June 2014 using a semi-automated algorithm [21,22]. In short, an algorithm was used to calculate a nosocomial infection index (NII) which was then verified by infection control practitioners (ICP) in case of a positive outcome to determine whenever HAI was present or not. All patients with a NII \u0026gt; 7 are verified by an ICP, and a definite outcome SSI was concluded by the ICP using the electronic patient data system.\u003c/p\u003e\n\u003cp\u003eWe included 3,250 surgical procedures, performed on 2,929 distinct patients. Data were extracted from a centralised database, containing cross-departmental data, and clinical synopsis reports, infectious disease consultation reports, laboratory results and imaging reports. Surgeries were included if they form part of the three types of surgeries under investigation in this study and had a point prevalence study within 30 days after the surgery took place. If the surgery took place within 30 days after an included surgery, then the latter surgery was excluded.\u003c/p\u003e\n\u003cp\u003e\u003ca name=\"_Hlk526962285\"/\u003eThe data used for this study were anonymized in accordance to the Dutch Personal Data Protection Act (WBP). Approval of the Medical Ethical Committee was obtained (MEC-2018-1185). There was no need to obtain informed consent because this is a fully anonymous retrospective study and no further interaction with the patients were necessary.\u003c/p\u003e\n\u003cp\u003eRisk factors relating to digestive system surgical procedures, thoracic surgery and orthopaedic procedures were identified from existing literature using the corresponding medical subject headings (MeSH). For a risk factor to be included in this study, it had to be significant in the multivariate analysis of the literature considered. The risk factors which are common to all three groups of surgeries, according to our literature scan, are called “general risk factors”. \u003c/p\u003e\n\u003cp\u003e\u003cb\u003e\u003ca name=\"_Ref525197065\"/\u003eStatistical analysis\u003c/b\u003e\u003c/p\u003e\n\u003cp\u003e\u003ca name=\"_Hlk526962323\"/\u003eDuring the initial analysis of the data, a missing value analysis is performed. Using IBM SPSS Statistics for Windows, Version 25, we performed t-tests to determine if the differences in the averages of variables with missing values and those without were statistically significant. These tests, together with Little’s MCAR test, convinced us that the missing values were not completely randomly missing and that we could not make use of more simple imputation methods. We chose to use conditional Markov chain Monte Carlo (MCMC) with multiple imputations for the imputation process. [23,24]\u003c/p\u003e\n\u003cp\u003eTests for significant differences in the occurrence of SSI across all three groups of surgeries were performed using the Wilcoxon-Kruskal-Wallis test for continuous variables and Pearson chi-square test for categorical variables. In this study we consider variables to be statistically significant if the corresponding p-value is less than 0.05.\u003c/p\u003e\n\u003cp\u003eIn order to build a prognostic prediction model for SSI, Hosmer et al. suggests fitting a univariate logistic regression model to each variable separately and if the p-value is less than a certain p-value, 0.1 is this case, then consider the variable good enough to include in the multivariate logistic regression model. [26] The data were split according to the different groups of surgeries in order to evaluate them separately. A univariate analysis was performed for each of the three groups of surgeries using all the variables identified across the three different groups. Significant variables in the univariate analysis are then also added to the list of variables associated with each group of surgery, together with the variables identified from the literature. This results in an extended list of general risk factors as more risk factors are common across the three groups of surgeries.\u003c/p\u003e\n\u003cp\u003eA multivariate logistic regression model was applied using a forward stepwise approach.(28) The multivariate model was first built using the general risk factors and then, using the result as a starting point, the surgery group specific risk factors were added to the model in order of the Akaike information criterion (AIC) until convergence is reached. In this case, we chose the conversion of the model to imply that there are no additional variables which can be added which will be statistically significant with a p-value of less than 0.05 or an AIC of 3.8415. \u003c/p\u003e\n\u003cp\u003eEach variable contributes information about the SSI outcome variable, which in turn reduces the error or residual of the model. For a logistic regression model, the residual or error can be stated in terms of deviance. To determine the importance of the different variables in the final model, we calculate the difference in model deviance caused by the exclusion of each variable. Model performance are determined using the Gini coefficient after each step of the multivariate modelling process and the difference is reported as the marginal contribution of surgery group specific risk factors for this study. [27]\u003c/p\u003e"},{"header":"Results","content":"\u003cp\u003eIn total, 55 risk factors were identified across the three types of surgical procedures from literature [15], [18–28]. Of the risk factors identified, ASA class, body mass index (BMI), Preoperative length of stay and diabetes were identified as general risk factors. The complete list of risk factors identified from literature can be found in Table 6 as part of the Appendix. There are 24 risk factors unique to digestive system surgical procedures, 14 to orthopaedic procedures and 15 to thoracic surgeries. Of the 55 risk factors identified from the literature, 23 could be extracted from our own data to use in this study. These 23 risk factors included in this study, together with the number of surgery groups they occurred in (N), are shown in Table 1. \u003c/p\u003e\n\u003cp class=\"caption\"\u003e\u003ca name=\"_Ref2066019\"/\u003eTable 1: Variables names and definitions used to investigate the future occurrence of SSI in this study\u003c/p\u003e\n\u003ctable class=table\u003e\u003ctbody\u003e\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003eVariable\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003eAbbreviation\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003eN\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003eDefinition\u003c/p\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003eDemographic\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003eGender\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003eGEN\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e2\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003eGender of patient\u003c/p\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003eAge\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003eAGE\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e2\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003eAge of patient \u003c/p\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003eASA class\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003eASA\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e3\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003eASA class of patient\u003c/p\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003eBMI\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003eBMI\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e3\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003eBMI of patient at the time of surgery.\u003c/p\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003eBehavioural\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003eAlcohol use\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003eALC\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e2\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003eAlcohol use of patient at the time of surgery.\u003c/p\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003eSmoking\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003eSMO\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e2\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003eSmoking status of patient at the time of surgery.\u003c/p\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003eComorbidities\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003eHeart disease\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003eHEA\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e2\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003ePatient has a history of heart disease at the time of surgery.\u003c/p\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003eLiver disease\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003eLIV\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e2\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003ePatient has a history of heart liver at the time of surgery.\u003c/p\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003eHepatitis\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003eHEP\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e1\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003eHepatitis of patient at the time of surgery.\u003c/p\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003eHyper tension\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003eHYP\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e1\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003ePatient has a history of hyper tension.\u003c/p\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003eDiabetes\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003eDIA\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e3\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003eDiabetes of patient at the time of surgery.\u003c/p\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003eMeasurement\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003eHighest temperature\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003eTEM\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e1\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003eHighest temperature of patient in the past 7 days before surgery.\u003c/p\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003eHighest CRP\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003eCRP\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e1\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003eHighest CRP of patient in the past 7 days before surgery.\u003c/p\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003eHighest Leukocyte\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003eLEU\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e2\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003eHighest Leukocyte of patient in the past 7 days before surgery.\u003c/p\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003eHighest protein\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003ePRO\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e1\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003eHighest protein of patient in the past 7 days before surgery.\u003c/p\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003eHighest alkaline phosphatase\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003eALK\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e1\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003eHighest alkaline phosphatase of patient in the past 7 days before surgery.\u003c/p\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003eHighest glucose\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003eGLU\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e1\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003eHighest glucose of patient in the past 7 days before surgery.\u003c/p\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003eHighest haemoglobin\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003eHEM\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e1\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003eHighest haemoglobin of patient in the past 7 days before surgery.\u003c/p\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003eHighest thrombocyte\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003eTHR\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e1\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003eHighest thrombocyte of patient in the past 7 days before surgery.\u003c/p\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003eOperative\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003ePreoperative length of stay (days)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003eLOS\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e3\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003ePreoperative length of stay (days) of patient at the time of surgery.\u003c/p\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003eAntibiotic use\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003eANT\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e1\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003eAntibiotic use of patient at the time of surgery.\u003c/p\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003eUrgency\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003eURG\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e2\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003eUrgency of the surgical procedure.\u003c/p\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003eDuration of surgery\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003eDUR\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e2\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003eDuration of the surgical procedure.\u003c/p\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003c/tbody\u003e\u003c/table\u003e\n\u003cp/\u003e\n\u003cp\u003eThe test for differences for risk factors in Table 1 are shown in Table 2. The variables indicating the type of surgery was statistically significant but there was no significant difference between the ASA classes of patients for which SSI occurred. Diabetes and BMI were also not significant. Preoperative length of stay was the only general risk factor which was statistically significant. Antibiotics use, temperature and CRP were significant during initial analysis across the groups of surgeries with pvalue of less than 0.001. \u003c/p\u003e\n\u003cp class=\"caption\"\u003e\u003ca name=\"_Ref2068513\"/\u003eTable 2: Test for differences preoperative and operative characteristic for the occurrence of SSI\u003c/p\u003e\n\u003ctable class=table\u003e\u003ctbody\u003e\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003eVariable\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003eSSI = No (3.078)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003eSSI = Yes (172)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003ep-value\u003c/p\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003eGender\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003eFemale\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e1243 (95.2)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e63 (4.8)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e0.328\u003c/p\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003eMale\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e1835 (94.4)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e109 (5.6)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003eAge\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e46.7 (26)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e49 (23.5)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e0.522\u003c/p\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003eASA class\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003eASA CLASS I\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e426 (96.6)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e15 (3.4)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e0.124\u003c/p\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003eASA CLASS II\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e1043 (94.6)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e60 (5.4)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003eASA CLASS III\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e1239 (94.8)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e68 (5.2)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003eASA CLASS IV\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e356 (93.0)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e27 (7.0)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003eASA CLASS V\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e14 (87.5)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e2 (12.5)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003eBMI\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e24.8 (5.1)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e24.7 (4.7)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e0.966\u003c/p\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003eAlcohol use\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003eCurrent\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e1702 (95.0)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e89 (5.0)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e0.659\u003c/p\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003eNever\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e1180 (94.3)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e71 (5.7)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003ePast\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e196 (94.2)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e12 (5.8)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003eSmoking\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003eCurrent\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e1396 (93.3)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e101 (6.7)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e0.002\u003c/p\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003eNever\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e978 (95.7)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e44 (4.3)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003ePast\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e704 (96.3)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e27 (3.7)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003eHeart disease\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003eNo\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e2942 (94.8)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e161 (5.2)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e0.225\u003c/p\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003eYes\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e136 (92.5)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e11 (7.5)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003eLiver disease\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003eNo\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e2989 (94.7)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e166 (5.3)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e0.651\u003c/p\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003eYes\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e89 (93.7)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e6 (6.3)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003eHepatitis\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003eNo\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e3015 (94.6)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e171 (5.4)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e0.178\u003c/p\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003eYes\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e63 (98.4)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e1 (1.6)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003eHyper tension\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003eNo\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e2440 (94.5)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e142 (5.5)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e0.299\u003c/p\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003eYes\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e638 (95.5)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e30 (4.5)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003eDiabetes\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003eNo\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e2807 (94.9)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e151 (5.1)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e0.129\u003c/p\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003eYes\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e271 (92.8)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e21 (7.2)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003eHighest temperature\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e38.1 (0.9)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e38.9 (1)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e\u0026lt;0.001\u003c/p\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003eHighest CRP\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e38.8 (69.3)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e81.8 (105.2)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e\u0026lt;0.001\u003c/p\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003eHighest Leukocyte\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e11.6 (6.7)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e12.6 (7.1)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e0.06\u003c/p\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003eHighest protein\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e63.1 (10.4)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e59.3 (11.8)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e\u0026lt;0.001\u003c/p\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003eHighest alkaline phosphatase\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e110.3 (102.5)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e123.3 (104.1)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e0.04\u003c/p\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003eHighest glucose\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e9.4 (3.3)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e10.1 (3.5)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e0.002\u003c/p\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003eHighest haemoglobin\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e8.1 (1.2)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e8 (1.3)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e0.262\u003c/p\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003eHighest thrombocyte\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e207.8 (103.7)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e171.6 (92.9)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e\u0026lt;0.001\u003c/p\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003ePreoperative length of stay (days)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e6.4 (24.5)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e10 (28.8)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e\u0026lt;0.001\u003c/p\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003eAntibiotic use\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003eNo\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e2051 (97.7)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e49 (2.3)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e\u0026lt;0.001\u003c/p\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003eYes\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e1027 (89.3)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e123 (10.7)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003eType of surgery\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003eDigestive System Surgical Procedures\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e1010 (90.5)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e106 (9.5)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e\u0026lt;0.001\u003c/p\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003eOrthopaedic Procedures\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e941 (97.1)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e28 (2.9)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003eThoracic Surgery\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e1127 (96.7)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e38 (3.3)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003eUrgency\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003eElective\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e1586 (96.4)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e59 (3.6)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e\u0026lt;0.001\u003c/p\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003eEmergency\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e1492 (93.0)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e113 (7.0)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003eDuration of surgery\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e245.1 (131.1)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e274.4 (163.2)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e0.125\u003c/p\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003c/tbody\u003e\u003c/table\u003e\n\u003cp/\u003e\n\u003cp\u003eThe significant univariate results of digestive system, orthopaedic and thoracic surgical procedures are shown in Table 3 and the full results can be found in Table 5, Table 6 and Table 7 in the Appendix. Antibiotic use, age, Leukocyte, temperature and smoking status were added to the list of general risk factors after being found statistically significant in the univariate analysis – increasing the number of general risk factors to 9. BMI and diabetes were two risk factors identified as general Risk factors from the literature but were not found significant in any of the three univariate analyses in our own study. \u003c/p\u003e\n\u003cp class=\"caption\"\u003e\u003ca name=\"_Ref2255691\"/\u003eTable 3: Digestive system surgical procedures: univariate analysis of risk factors for the future occurrence of SSI\u003c/p\u003e\n\u003ctable class=table\u003e\u003ctbody\u003e\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003eCharacteristic\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003eSSI = No (3.078)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003eSSI = Yes (172)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003eUnivariate OR (95% CI, p-value)\u003c/p\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003e\u003cb\u003eDigestive system surgical procedures\u003c/b\u003e\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003eAge\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003e23\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e310 (30.7)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e9 (8.5)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003e23\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e700 (69.3)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e97 (91.5)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e4.77 (2.51-10.28, p\u0026lt;0.001)\u003c/p\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003eASA class\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003eASA CLASS I\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e140 (13.9)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e6 (5.7)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003eASA CLASS II\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e452 (44.8)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e46 (43.4)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e2.37 (1.07-6.31, p=0.052)\u003c/p\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003eASA CLASS III\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e343 (34.0)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e40 (37.7)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e2.72 (1.21-7.28, p=0.026)\u003c/p\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003eASA CLASS IV\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e75 (7.4)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e14 (13.2)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e4.36 (1.67-12.73, p=0.004)\u003c/p\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003eSmoking\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003eCurrent\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e492 (48.7)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e67 (63.2)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003eNever\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e337 (33.4)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e20 (18.9)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e0.44 (0.25-0.72, p=0.002)\u003c/p\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003ePast\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e181 (17.9)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e19 (17.9)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e0.77 (0.44-1.29, p=0.342)\u003c/p\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003eHighest temperature\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003e38\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e647 (64.1)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e28 (26.4)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003e(38,39]\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e243 (24.1)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e40 (37.7)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e3.80 (2.31-6.36, p\u0026lt;0.001)\u003c/p\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003e39\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e120 (11.9)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e38 (35.8)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e7.32 (4.34-12.47, p\u0026lt;0.001)\u003c/p\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003eHighest CRP\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003e164\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e905 (89.6)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e75 (70.8)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003e164\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e105 (10.4)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e31 (29.2)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e3.56 (2.22-5.63, p\u0026lt;0.001)\u003c/p\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003eHighest protein\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003e57\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e321 (31.8)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e53 (50.0)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003e57\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e689 (68.2)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e53 (50.0)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e0.47 (0.31-0.70, p\u0026lt;0.001)\u003c/p\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003eHighest glucose\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003e8.2\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e494 (48.9)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e31 (29.2)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003e8.2\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e516 (51.1)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e75 (70.8)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e2.32 (1.51-3.63, p\u0026lt;0.001)\u003c/p\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003eHighest thrombocyte\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003e225\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e692 (68.5)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e95 (89.6)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003e225\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e318 (31.5)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e11 (10.4)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e0.25 (0.13-0.46, p\u0026lt;0.001)\u003c/p\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003eAntibiotic use\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003eNo\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e581 (57.5)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e19 (17.9)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003eYes\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e429 (42.5)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e87 (82.1)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e6.20 (3.80-10.64, p\u0026lt;0.001)\u003c/p\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003eUrgency\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003eElective\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e548 (54.3)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e34 (32.1)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003eEmergency\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e462 (45.7)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e72 (67.9)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e2.51 (1.65-3.89, p\u0026lt;0.001)\u003c/p\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003eDuration of surgery\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003e530\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e971 (96.1)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e89 (84.0)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003e530\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e39 (3.9)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e17 (16.0)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e4.76 (2.53-8.62, p\u0026lt;0.001)\u003c/p\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003e\u003cb\u003eOrthopaedic surgical procedures\u003c/b\u003e\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003eHighest temperature\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003e38\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e747 (79.4)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e15 (53.6)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003e38\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e194 (20.6)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e13 (46.4)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e3.34 (1.54-7.14, p=0.002)\u003c/p\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003eHighest CRP\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003e144\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e883 (93.8)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e20 (71.4)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003e144\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e58 (6.2)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e8 (28.6)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e6.09 (2.44-13.96, p\u0026lt;0.001)\u003c/p\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003eHighest Leukocyte\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003e17.3\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e820 (87.1)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e17 (60.7)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003e17.3\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e121 (12.9)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e11 (39.3)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e4.39 (1.95-9.48, p\u0026lt;0.001)\u003c/p\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003ePreoperative length of stay (days)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003e7\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e853 (90.6)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e16 (57.1)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003e7\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e88 (9.4)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e12 (42.9)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e7.27 (3.27-15.79, p\u0026lt;0.001)\u003c/p\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003eAntibiotic use\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003eNo\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e720 (76.5)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e11 (39.3)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003eYes\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e221 (23.5)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e17 (60.7)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e5.03 (2.35-11.23, p\u0026lt;0.001)\u003c/p\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003e\u003cb\u003eThoracic surgical procedure\u003c/b\u003e\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003eAge\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003e17\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e246 (21.8)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e17 (44.7)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003e17\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e881 (78.2)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e21 (55.3)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e0.34 (0.18-0.67, p=0.001)\u003c/p\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003eSmoking\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003eCurrent\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e525 (46.6)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e22 (57.9)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003eNever\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e316 (28.0)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e13 (34.2)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e0.98 (0.48-1.95, p=0.959)\u003c/p\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003ePast\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e286 (25.4)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e3 (7.9)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e0.25 (0.06-0.73, p=0.025)\u003c/p\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003eHighest temperature\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003e37\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e316 (28.0)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e2 (5.3)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003e(37,38]\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e612 (54.3)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e20 (52.6)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e5.16 (1.50-32.47, p=0.027)\u003c/p\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003e38\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e199 (17.7)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e16 (42.1)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e12.70 (3.56-80.90, p=0.001)\u003c/p\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003eAntibiotic use\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003eNo\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e750 (66.5)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e19 (50.0)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003eYes\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e377 (33.5)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e19 (50.0)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e1.99 (1.04-3.82, p=0.037)\u003c/p\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003eUrgency\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003eElective\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e605 (53.7)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e14 (36.8)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003eEmergency\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e522 (46.3)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e24 (63.2)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e1.99 (1.03-3.98, p=0.044)\u003c/p\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003c/tbody\u003e\u003c/table\u003e\n\u003cp/\u003e\n\u003cp\u003eThe general risk factors which were significant for digestive system surgical procedures were antibiotic use, temperature, smoking status and age according to the multivariate analysis results shown in Table 4. The additional significant risk factors, indicated in bold, which were unique to the digestive system surgery group, were CRP, thrombocyte, duration of the surgery and if the surgery was an elective or not. In this case, the general risk factors reduced the residual deviance from 700.66 to 570.24. The risk factors identified to be unique to digestive system surgical procedures reduced the residual deviance from 570.24 to 531.05 and improved the Gini coefficient from 0.63 to 0.69. Important to know, the variables CRP and thrombocyte were the biggest contributors in the increase in model performance with both decreasing the residual deviance by almost 14. Pre-operative length of stay, antibiotic use and Leukocyte were significant general risk factor for the orthopaedic group of surgeries, resulting in a Gini coefficient of 0.6. Temperature, age and antibiotic use were significant general risk factors for the thoracic group of surgical procedures and produced a Gini coefficient of 0.51. Neither the orthopaedic nor the thoracic group of surgical procedures had any significant risk factors unique to the group of surgeries.\u003c/p\u003e\n\u003cp class=\"caption\"\u003e\u003ca name=\"_Ref2070851\"/\u003e\u003ca name=\"_Hlk4433735\"/\u003eTable 4: Multivariate analysis of risk factors for the future occurrence of SSI by group of surgeries (Risk factors in bold are the additional risk factors not part of the general risk factors)\u003c/p\u003e\n\u003ctable class=table\u003e\u003ctbody\u003e\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003eSurgery type \u0026amp; variable\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003eCoefficient\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003eMultivariate OR\u003c/p\u003e\n\u003cp\u003e(95% CI)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003ep-value\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003eResidual deviance\u003c/p\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003eDigestive System Surgical Procedures\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003e(Intercept)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e-4.560\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e 0.010 (0.004 - 0.024) \u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e \u0026lt;0.001 \u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e 700.660 \u003c/p\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003eAntibiotic use Yes\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e0.911\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e 2.488 (1.355 - 4.797) \u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e 0.005 \u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e 636.770 \u003c/p\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003eHighest temperature (38, 39]\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e0.962\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e 2.616 (1.526 - 4.527) \u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e \u0026lt;0.001 \u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e 588.810 \u003c/p\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003eHighest temperature 39\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e1.757\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e 5.796 (3.226 - 10.517) \u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e \u0026lt;0.001 \u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e 588.810 \u003c/p\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003eSmoking = Never\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e-0.929\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e 0.395 (0.218 - 0.688) \u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e \u0026lt;0.001 \u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e 578.020 \u003c/p\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003eSmoking = Past\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e-0.551\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e 0.577 (0.308 - 1.040) \u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e 0.075 \u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e 578.020 \u003c/p\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003eAge 23\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e1.122\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e 3.071 (1.347 - 7.578) \u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e 0.010 \u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e 570.240 \u003c/p\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003e\u003cb\u003eHighest CRP 164\u003c/b\u003e\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e\u003cb\u003e1.074\u003c/b\u003e\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e\u003cb\u003e 2.928 (1.681 - 5.038) \u003c/b\u003e\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e\u003cb\u003e \u0026lt;0.001 \u003c/b\u003e\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e\u003cb\u003e 556.300 \u003c/b\u003e\u003c/p\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003e\u003cb\u003eHighest thrombocyte 225\u003c/b\u003e\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e\u003cb\u003e-0.983\u003c/b\u003e\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e\u003cb\u003e 0.374 (0.179 - 0.720) \u003c/b\u003e\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e\u003cb\u003e 0.005 \u003c/b\u003e\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e\u003cb\u003e 542.650 \u003c/b\u003e\u003c/p\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003e\u003cb\u003eDuration of surgery 530\u003c/b\u003e\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e\u003cb\u003e1.221\u003c/b\u003e\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e\u003cb\u003e 3.390 (1.612 - 6.957) \u003c/b\u003e\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e\u003cb\u003e \u0026lt;0.001 \u003c/b\u003e\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e\u003cb\u003e 535.180 \u003c/b\u003e\u003c/p\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003e\u003cb\u003eUrgency Emergency\u003c/b\u003e\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e\u003cb\u003e0.529\u003c/b\u003e\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e\u003cb\u003e 1.698 (1.018 - 2.883) \u003c/b\u003e\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e\u003cb\u003e 0.045 \u003c/b\u003e\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e\u003cb\u003e 531.050 \u003c/b\u003e\u003c/p\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003eOrthopaedic Surgical Procedures\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003e(Intercept)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e-4.682\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e 0.009 (0.004 - 0.017) \u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e\u0026lt;0.001\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e 253.650 \u003c/p\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003ePreoperative length of stay7\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e1.552\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e 4.721 (2.035 - 10.674) \u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e\u0026lt;0.001\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e 232.920 \u003c/p\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003eAntibiotic use Yes\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e1.224\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e 3.402 (1.521 - 7.839) \u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e 0.003 \u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e 223.240 \u003c/p\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003eHighest Leukocyte 17.3\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e1.254\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e 3.505 (1.511 - 7.819) \u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e 0.003 \u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e 215.080 \u003c/p\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003eThoracic Surgical Procedures\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003e(Intercept)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e-4.195\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e 0.015 (0.002 - 0.053) \u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e\u0026lt;0.001\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e 334.890 \u003c/p\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003eHighest temperature (37,38]\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e1.311\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e 3.709 (1.055 - 23.515) \u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e 0.081 \u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e 315.670 \u003c/p\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003eHighest temperate 38\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e1.826\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e 6.209 (1.676 - 40.324) \u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e 0.018 \u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e 315.670 \u003c/p\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003eAge 17\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e-1.742\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e 0.175 (0.062 - 0.463) \u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e\u0026lt;0.001\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e 311.810 \u003c/p\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003eAntibiotic use Yes\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e1.549\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e 4.708 (1.846 - 13.172) \u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e 0.002 \u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e 300.860 \u003c/p\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003c/tbody\u003e\u003c/table\u003e\n\u003cp/\u003e\n\u003cp\u003eThe resultant equations of the multivariate logistic regression models are provided in Equation 1 to Equation 3. The abbreviations of the variable names are provided in Table 1.\u003c/p\u003e\n\u003cp/\u003e\n\u003cp/\u003e\n\u003cp/\u003e\n\u003cp\u003eWe summarise the findings concerning the statistical significance of the risk factors by surgical procedure in Table 5. The stage of significance indicates the last stage of the analysis where this risk factor was statistically significant for corresponding group of surgeries. The source indicates where the reason why each risk factor was considered for each group of surgeries. In the last section we see the risk factors we found in literature but were not significant for any of the groups of surgeries for both the univariate and multivariate analysis. Risk factors which were significant in the multivariate analysis, but not the univariate analysis are shown in the first part of Table 5.\u003c/p\u003e\n\u003cp class=\"caption\"\u003e\u003ca name=\"_Ref4433855\"/\u003eTable 5: Statistical significance of risk factors and the source which lead them to be considered by surgical procedure\u003c/p\u003e\n\u003ctable class=table\u003e\u003ctbody\u003e\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003e\u003cb\u003eStage of significance (Source)\u003c/b\u003e\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e\u003cb\u003eDigestive System\u003c/b\u003e\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e\u003cb\u003eOrthopaedic\u003c/b\u003e\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e\u003cb\u003eThoracic\u003c/b\u003e\u003c/p\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003eMultivariate Analysis (\u003cb\u003eLiterature\u003c/b\u003e)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003eAge\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e*\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003ePreoperative length of stay (days)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e*\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003eDuration of surgery\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e*\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003eHighest temperature\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e*\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003eHighest thrombocyte\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e*\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003eSmoking\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e*\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003eUrgency\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e*\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003eMultivariate Analysis (\u003cb\u003eUnivariate Analysis\u003c/b\u003e)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003eAntibiotic use\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e*\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e*\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e*\u003c/p\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003eAge\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e*\u003c/p\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003eHighest CRP\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e*\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003eHighest Leukocyte\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e*\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003eHighest temperature\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e*\u003c/p\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003eUnivariate Analysis (\u003cb\u003eLiterature\u003c/b\u003e)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003eASA class\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e*\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003eHighest CRP\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e*\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003eHighest glucose\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e*\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003eHighest Leukocyte\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e*\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003eHighest protein\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e*\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003eUrgency\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e*\u003c/p\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003eUnivariate Analysis (\u003cb\u003eUnivariate Analysis\u003c/b\u003e)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003eHighest temperature\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e*\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003eSmoking\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e*\u003c/p\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003eNone (\u003cb\u003eLiterature\u003c/b\u003e)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003eAge\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e*\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003eASA class\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e*\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e*\u003c/p\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003eBMI\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e*\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e*\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e*\u003c/p\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003ePreoperative length of stay (days)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e*\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e*\u003c/p\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003eDiabetes\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e*\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e*\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e*\u003c/p\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003eAlcohol use\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e*\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e*\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003eDuration of surgery\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e*\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003eGender\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e*\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e*\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003eHeart disease\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e*\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e*\u003c/p\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003eHepatitis\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e*\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003eHighest alkaline phosphatase\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e*\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003eHighest haemoglobin\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e*\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003eHighest Leukocyte\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e*\u003c/p\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003eHyper tension\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e*\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003eLiver disease\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e*\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e*\u003c/p\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003eSmoking\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e \u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e*\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e \u003c/p\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003c/tbody\u003e\u003c/table\u003e"},{"header":"Discussion","content":"\u003cp\u003eWe aimed to identify general risk factors, common across three groups of surgeries, using literature and univariate analysis to quantify the marginal contribution of the risk factors not common to those three groups of surgeries. \u003c/p\u003e\n\u003cp\u003eFrom the literature we could identify ASA class, BMI, preoperative length of stay (days) and diabetes as general risk factors. We added antibiotic use, age, Leukocyte, temperature and smoking status as to the list of general risk factors by using the results of the univariate analysis. These risk factors might have been overlooked should this study have focussed on only one type of surgery. Using this process, researchers may find useful risk factors to explain the future occurrence of SSI in their own environment, but not generally reported by literature of the specific type of surgery under investigation.\u003c/p\u003e\n\u003cp\u003eThis study produced three prognostic prediction models (Equation 1 – 3) for the future occurrence of SSI within a 30 days period after undergoing one of the three group of surgical procedures. Using existing literature and the results of the univariate analysis, we identified general risk factors across three groups of surgical procedures and showed that the marginal contribution for models predicting SSI could be up to 9.5% in terms of discriminatory power by including surgery group specific risk factors. We also showed that this benefit can be measured in terms of reduced model error and ability to discriminate using the Gini as performance measure.\u003c/p\u003e\n\u003cp\u003eThe initial results of the missing data analysis revealed that the variables relating to the CRP and Leukocyte levels have a sizeable amount of missing values. The difference in the preoperative length of stay led us to believe that most of these missing values were caused by patients who did not stay sufficiently long in the hospital to have the laboratory tests before the surgical procedure took place. A possible explanation could be that most of the missing values were due to short-stay elective or emergence surgery patients or the absence of signs of infections which would lead to not requesting this chemical test. These laboratory tests are usually only done in case the patient is suspected of already having an infection. Our conclusion was that final model might be prone to overestimate the probability of SSI since the missing values were imputed using data from patients with greater risk of infection. \u003c/p\u003e\n\u003cp\u003eWe used a 30-day outcome period in which we observe if an SSI was present or not, but according the CDC definition, this outcome period should be 1 year for surgical implantation procedures. Since our data only spans over 18 months, it was not possible to use a 12-month outcome windows for all surgical implantation procedures, which is a limitation of this study. Another limitation is that for all three groups of surgical procedures, the use of antibiotics is predictive of occurrence of SSI. This could mean that the patient is already fighting off some kind infection and is receiving treatment for a present condition which has nothing to do with the surgery under investigation. This study was performed in as a single centre study, which limits the generalisability of this study. Future research can repeat this research on multiple patient populations in order produce more generalisable results. \u003c/p\u003e\n\u003cp\u003eThe predictive models were designed with the aim to use it to investigate more variables as potential risk factors for the future occurrence of SSI, 30 days after a surgical procedure. The administration of prophylaxis and the optimal timing thereof is an important risk factor however, these data were not available, but in future we recommend that these data should also be included in similar studies. Although some research has been done in this regard, to our knowledge, it has not been done for this patient population and confounders identified in this study. \u003c/p\u003e\n\u003cp\u003eThe length of stay before a surgical procedure had mixed outcomes as a risk factor in the literature. Abuzaid et al. found it to be not significantly associated with SSI after isolated coronary artery bypass grafting, while Sang et al. found it to be highly significant [5,7]. Preoperative length of stay can also be a proxy for the severity of a patient’s condition, if we assume that patients in worse conditions are more likely to have been in hospital for a longer period before undergoing a surgical procedure. This variable was significant in both the univariate and multivariate case for the orthopaedic surgeries group. The cause of the increased lengths of stay could be investigated as a potential modifiable risk factor.\u003c/p\u003e\n\u003cp\u003eAnother opportunity for future research is to investigate which risk factors are predictive for the occurrence of SSI over different time periods. Doing this will enable healthcare workers to identify which risk factors explain the occurrence of SSI soon after surgery and which are better explain the occurrence of SSI nearing the end of the 30-day period or even later for implantation surgeries. This can help set guidelines to determine the vigilance necessary to mitigate the risk of SSI on a patient level. \u003c/p\u003e"},{"header":"Conclusion","content":"\u003cp\u003eWe identified ASA class, body mass index (BMI), Preoperative length of stay, diabetes, antibiotic use, age, Leukocyte, temperature and smoking status as general risk factors common to digestive, orthopaedic and thoracic surgical procedures using existing literature and univariate logistic regression. We used a systematic approach to quantify the marginal contribution of the surgical procedure group specific risk factors using the results of a serial prevalence study and retrospective medical data. For digestive system surgical procedures, it is possible to increase the predictive power to explain the future occurrence of SSI by 9.5% by including CRP, thrombocyte, duration of the surgery and if the surgery will be elective or not. Pre-operative length of stay, antibiotic use and Leukocyte were significant general risk factor for the orthopaedic group of surgeries. Temperature, age and antibiotic use were significant general risk factors for the thoracic group of surgical procedures. Neither the orthopaedic nor the thoracic group of surgical procedures predictive risk factors unique to the group of surgeries. This is important because these results can help healthcare workers provided better preoperative counselling and aid researchers in identifying potentially modifiable risk factors in future research.\u003c/p\u003e"},{"header":"List of abbreviations","content":"\u003cp\u003eAIC Akaike information criterion \u003c/p\u003e\n\u003cp\u003eASA American society of anaesthesiologists\u003c/p\u003e\n\u003cp\u003eATC Anatomical therapeutic chemical\u003c/p\u003e\n\u003cp\u003eAUC Area under the curve\u003c/p\u003e\n\u003cp\u003eBSI Bloodstream infection\u003c/p\u003e\n\u003cp\u003eCDC Centers for disease control and prevention \u003c/p\u003e\n\u003cp\u003eCRP C-reactive protein\u003c/p\u003e\n\u003cp\u003eECDC European centre for disease prevention and control\u003c/p\u003e\n\u003cp\u003eHAI Healthcare associated infection\u003c/p\u003e\n\u003cp\u003eICP Infection control practitioner\u003c/p\u003e\n\u003cp\u003eLRTI Lower respiratory tract infection\u003c/p\u003e\n\u003cp\u003eMCAR Missing completely at random\u003c/p\u003e\n\u003cp\u003eMCMC Markov chain Monte Carlo\u003c/p\u003e\n\u003cp\u003eMEC Medical ethical committee \u003c/p\u003e\n\u003cp\u003eMeSH Medical subject headings \u003c/p\u003e\n\u003cp\u003eNHSN National health safety network \u003c/p\u003e\n\u003cp\u003eNII Nosocomial infection index \u003c/p\u003e\n\u003cp\u003eROC Receiver operator characteristic\u003c/p\u003e\n\u003cp\u003eSAP Surgical antimicrobial prophylaxis\u003c/p\u003e\n\u003cp\u003eSSI Surgical site infections \u003c/p\u003e\n\u003cp\u003eSSI Surgical site infections \u003c/p\u003e\n\u003cp\u003eUTI Urinary tract infection\u003c/p\u003e\n\u003cp\u003eWBP Dutch personal data protection act\u003c/p\u003e"},{"header":"Declarations","content":"\u003cp\u003e\u003cb\u003eEthics approval and consent to participate\u003c/b\u003e\u003c/p\u003e\n\u003cp\u003eApproval from Medical Ethical Committee of Erasmus MC (MEC-2018-1185)\u003c/p\u003e\n\u003cp\u003e\u003cb\u003eConsent for publication\u003c/b\u003e\u003c/p\u003e\n\u003cp\u003eAll authors read and approved the manuscript.\u003c/p\u003e\n\u003cp\u003e\u003cb\u003eAvailability of data and material\u003c/b\u003e\u003c/p\u003e\n\u003cp\u003eThe data that support the findings of this study are available from Erasmus MC but restrictions apply to the availability of these data, which were used under license for the current study, and so are not publicly available. Data are however available from the authors upon reasonable request and with permission of Erasmus MC.\u003c/p\u003e\n\u003cp\u003e\u003cb\u003eCompeting interests\u003c/b\u003e\u003c/p\u003e\n\u003cp\u003eNone\u003c/p\u003e\n\u003cp\u003e\u003cb\u003eFunding\u003c/b\u003e\u003c/p\u003e\n\u003cp\u003eThe research was funded by Interreg VA, EurHealth-1Health project (\u003ca href=\"http://www.eurhealth-1health.eu/\"\u003ehttp://www.eurhealth-1health.eu/\u003c/a\u003e).\u003c/p\u003e\n\u003cp\u003e\u003cb\u003eAuthor’s contributions\u003c/b\u003e\u003c/p\u003e\n\u003cp\u003eJM, JEWC, A and MC contributed to the conceptualization of the research and commenting on the draft and final version of the paper. MC contributed as the main medical expert and provided guidance on all medical aspects of this study, including sourcing and understanding the data. MC, LMA, AF contributed in editing and writing the draft and final version of the paper. JM performed the data analysis, statistical analysis and wrote the draft and final version of the paper.\u003c/p\u003e\n\u003cp\u003e\u003cb\u003eAcknowledgements\u003c/b\u003e\u003c/p\u003e\n\u003cp\u003eWe would like to thank C. P. (Conrad) van der Hoeven, A.G.D (Arnim) Mulder and M. (Marius) Vogel for their help and constant willingness to help with questions regarding the data used for this study. Also, thanks to R. H. (Roel) Streefkerk for the work done to organise and combine the data as well as producing the SSI outcome variable used in this study.\u003c/p\u003e"},{"header":"References","content":"\u003cp\u003e1. European Centre for Disease Prevention and Control. Surveillance of surgical site infections in European hospitals – HAISSI protocol [Internet]. 2012. 1-47 p. Available from: http://www.ecdc.europa.eu/en/publications/Publications/120215_TED_SSI_protocol.pdf\u003c/p\u003e\n\u003cp\u003e2. Zarb P, Coignard B, Griskeviciene J, Muller A, Vankerckhoven V, Weist K, et al. point prevalence survey of healthcare-associated infections and antimicrobial use in European acute care hospitals. Vol. 17, Eurosurveillance. 2012. 1-16 p. \u003c/p\u003e\n\u003cp\u003e3. Jenks PJ, Laurent M, McQuarry S, Watkins R. Clinical and economic burden of surgical site infection (SSI) and predicted financial consequences of elimination of SSI from an English hospital. J Hosp Infect. 2014;86(1):24–33. \u003c/p\u003e\n\u003cp\u003e4. Westerman EL. Antibiotic prophylaxis in surgery: Historical background, rationa1e, and relationship to prospective payment. Am J Infect Control. 1984;12(6):339–43. \u003c/p\u003e\n\u003cp\u003e5. Leung S, Sang W, Chaturvedi R, Alam A, Samoukovic G, Varennes B De. Preoperative hospital length of stay as a modifiable risk factor for mediastinitis after cardiac surgery. J Cardiothorac Surg [Internet]. 2013;8(1):45. Available from: Journal of Cardiothoracic Surgery\u003c/p\u003e\n\u003cp\u003e6. Triantafyllopoulos G, Stundner O, Memtsoudis S, Poultsides LA. Patient, Surgery, and Hospital Related Risk Factors for Surgical Site Infections following Total Hip Arthroplasty. Sci World J. 2015;2015:1–9. \u003c/p\u003e\n\u003cp\u003e7. Abuzaid A, Zaki M, Al Tarief H. Potential risk factors for surgical site infection after isolated coronary artery bypass grafting in a Bahrain Cardiac Centre: A retrospective, case-controlled study. Hear Views. 2015;16(3):79. \u003c/p\u003e\n\u003cp\u003e8. Schimmel JJP, Horsting PP, de Kleuver M, Wonders G, van Limbeek J. Risk factors for deep surgical site infections after spinal fusion. Eur Spine J. 2010;19(10):1711–9. \u003c/p\u003e\n\u003cp\u003e9. Guohua X, cheng keping, Li J, Kong Q, Wang C, Nanyuan Y. Risk factors for surgical site infection in a teaching hospital: a prospective study of 1,138 patients. Patient Prefer Adherence. 2015;9:1171. \u003c/p\u003e\n\u003cp\u003e10. Gomila A, Carratalà J, Biondo S, Badia JM, Fraccalvieri D, Shaw E, et al. Predictive factors for early- and late-onset surgical site infections in patients undergoing elective colorectal surgery. A multicentre, prospective, cohort study. J Hosp Infect. 2018;99(1):24–30. \u003c/p\u003e\n\u003cp\u003e11. Martin ET, Kaye KS, Knott C, Nguyen H, Santarossa M, Evans R, et al. Diabetes and Risk of Surgical Site Infection: A Systematic Review and Meta-analysis. Infect Control Hosp Epidemiol. 2016;37(01):88–99. \u003c/p\u003e\n\u003cp\u003e12. Takahashi Y, Takesue Y, Fujiwara M, Tatsumi S, Ichiki K, Fujimoto J, et al. Risk factors for surgical site infection after major hepatobiliary and pancreatic surgery. J Infect Chemother [Internet]. 2018;24(9):739–43. Available from: https://doi.org/10.1016/j.jiac.2018.05.007\u003c/p\u003e\n\u003cp\u003e13. Silvestri M, Dobrinja C, Scomersi S, Giudici F, Turoldo A, Princic E, et al. Modifiable and non-modifiable risk factors for surgical site infection after colorectal surgery: a single-center experience. Surg Today. 2018;48(3):338–45. \u003c/p\u003e\n\u003cp\u003e14. Fukuda H. Patient-related risk factors for surgical site infection following eight types of gastrointestinal surgery. J Hosp Infect [Internet]. 2016;93(4):347–54. Available from: http://dx.doi.org/10.1016/j.jhin.2016.04.005\u003c/p\u003e\n\u003cp\u003e15. Kokudo T, Uldry E, Demartines N, Halkic N. Risk factors for incisional and organ space surgical site infections after liver resection are different. World J Surg. 2015;39(5):1185–92. \u003c/p\u003e\n\u003cp\u003e16. Isik O, Kaya E, Dundar HZ, Sarkut P. Surgical Site Infection: Re-assessment of the Risk Factors. Chirurgia (Bucur) [Internet]. 2015;110(5):457–61. Available from: http://www.ncbi.nlm.nih.gov/pubmed/26531790\u003c/p\u003e\n\u003cp\u003e17. Moreno Elola-Olaso A, Davenport DL, Hundley JC, Daily MF, Gedaly R. Predictors of surgical site infection after liver resection: A multicentre analysis using National Surgical Quality Improvement Program data. Hpb. 2012;14(2):136–41. \u003c/p\u003e\n\u003cp\u003e18. Lola I, Levidiotou S, Petrou A, Arnaoutoglou H, Apostolakis E, Papadopoulos GS. Are there independent predisposing factors for postoperative infections following open heart surgery? J Cardiothorac Surg [Internet]. 2011;6(1):151. Available from: http://cardiothoracicsurgery.biomedcentral.com/articles/10.1186/1749-8090-6-151\u003c/p\u003e\n\u003cp\u003e19. Chen LF, Arduino JM, Sheng S, Muhlbaier LH, Kanafani ZA, Harris AD, et al. Epidemiology and outcome of major postoperative infections following cardiac surgery: Risk factors and impact of pathogen type. Am J Infect Control. 2012;40(10):963–8. \u003c/p\u003e\n\u003cp\u003e20. Jolivet S, Lescure FX, Armand-Lefevre L, Raffoul R, Dilly MP, Ghodbane W, et al. Surgical site infection with extended-spectrum β-lactamase-producing Enterobacteriaceae after cardiac surgery: incidence and risk factors. Clin Microbiol Infect [Internet]. 2018;24(3):289–94. Available from: https://doi.org/10.1016/j.cmi.2017.07.004\u003c/p\u003e\n\u003cp\u003e21. Streefkerk RHRA, Moorman PW, Parlevliet GA, van der Hoeven C, Verbrugh HA, Vos MC, et al. An Automated Algorithm to Preselect Patients to Be Assessed Individually in Point Prevalence Surveys for Hospital-Acquired Infections in Surgery. Infect Control Hosp Epidemiol [Internet]. 2014;35(7):886–7. Available from: http://www.jstor.org/stable/info/10.1086/676868\u003c/p\u003e\n\u003cp\u003e22. Streefkerk RHRA, Borsboom GJJM, van der Hoeven CP, Vos MC, Verkooijen RP, Verbrugh HA. Evaluation of an Algorithm for Electronic Surveillance of Hospital-Acquired Infections Yielding Serial Weekly Point Prevalence Scores. Infect Control Hosp Epidemiol [Internet]. 2014 [cited 2017 Jul 18];35(07):888–90. Available from: https://www.cambridge.org/core/product/identifier/S0899823X00192372/type/journal_article\u003c/p\u003e\n\u003cp\u003e23. Asendorpf JB, Van De Schoot R, Denissen JJA, Hutteman R. Reducing bias due to systematic attrition in longitudinal studies: The benefits of multiple imputation. Int J Behav Dev. 2014;38(5):453–60. \u003c/p\u003e\n\u003cp\u003e24. Buuren S Van. Multiple imputation of discrete and continuous. Stat Methods Med Res. 2007;16(3):219–42. \u003c/p\u003e\n\u003cp\u003e25. Fayyad UM, Irani KB. Multi-Interval Discretization of Continuos-Valued Attributes for Classification Learning. Proc Int Jt Conf Uncertain AI. 1993;1022–7. \u003c/p\u003e\n\u003cp\u003e26. Hosmer DW, Lemeshow S. Applied logistic regression [Internet]. Wiley. 2000. 118-128 p. Available from: http://onlinelibrary.wiley.com/book/10.1002/9781118548387\u003c/p\u003e\n\u003cp\u003e27. Hanley JA, McNeil BJ. The meaning and use of the area under a receiver operating characteristic (ROC) curve. Radiology. 2014;143(1):29–36. \u003c/p\u003e\n\u003cp\u003e28. In Lee K, Koval JJ. Determination of the best significance level in forward stepwise logistic regression. Commun Stat - Simul Comput. 2007;26(2):559–75. \u003c/p\u003e\n\u003cp\u003e29. Liu J, Li N, Hao J, Li Y, Liu A, Wu Y, et al. Impact of the antibiotic stewardship program on prevention and control of surgical site infection during peri-operative clean surgery. Surg Infect (Larchmt). 2018;19(3):326–33. \u003c/p\u003e"},{"header":"Appendix","content":"\u003cp class=\"caption\"\u003e\u003ca name=\"_Ref4502828\"/\u003eTable 6: Variables identified from literature and present in the data sample by group of surgeries\u003c/p\u003e\n\u003ctable class=table\u003e\u003ctbody\u003e\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003eRisk Factor\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003eFound in data\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003eDigestive System\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003eOrthopaedic\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003eThoracic\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003eTotal\u003c/p\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003eASA class\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e1\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e1\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e1\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e1\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e3\u003c/p\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003eBMI\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e1\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e1\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e1\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e1\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e3\u003c/p\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003ePreoperative length of stay (days)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e1\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e1\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e1\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e1\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e3\u003c/p\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003eDiabetes\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e1\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e1\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e1\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e1\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e3\u003c/p\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003eAge\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e1\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e1\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e1\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e2\u003c/p\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003eAlcohol use\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e1\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e1\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e1\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e2\u003c/p\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003eDuration of surgery\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e1\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e1\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e1\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e2\u003c/p\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003eGender\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e1\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e1\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e1\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e2\u003c/p\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003eHeart disease\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e1\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e1\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e1\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e2\u003c/p\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003eHighest Leukocyte\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e1\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e1\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e1\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e2\u003c/p\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003eLiver disease\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e1\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e1\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e1\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e2\u003c/p\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003eSmoking\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e1\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e1\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e1\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e2\u003c/p\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003eUrgency\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e1\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e1\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e1\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e2\u003c/p\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003eHepatitis\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e1\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e1\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e1\u003c/p\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003eHighest alkaline phosphatase\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e1\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e1\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e1\u003c/p\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003eHighest CRP\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e1\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e1\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e1\u003c/p\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003eHighest glucose\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e1\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e1\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e1\u003c/p\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003eHighest haemoglobin\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e1\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e1\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e1\u003c/p\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003eHighest protein\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e1\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e1\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e1\u003c/p\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003eHighest temperature\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e1\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e1\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e1\u003c/p\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003eHighest thrombocyte\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e1\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e1\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e1\u003c/p\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003eHyper tension\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e1\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e1\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e1\u003c/p\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003eImmunosuppression\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e1\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e1\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e2\u003c/p\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003eAnaesthesia\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e1\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e1\u003c/p\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003eAntibiotic treatment in the previous 3 months\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e1\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e1\u003c/p\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003eBypass time\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e1\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e1\u003c/p\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003eCDC Surgical wound classification (SWC)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e1\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e1\u003c/p\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003eCerebrovascular accident\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e1\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e1\u003c/p\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003eChronic lung disease\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e1\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e1\u003c/p\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003eDialysis\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e1\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e1\u003c/p\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003eEstimated blood loss (EBL) \u0026gt; 600ml\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e1\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e1\u003c/p\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003eHistory of previous SSI\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e1\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e1\u003c/p\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003eHIV\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e1\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e1\u003c/p\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003eHospitalization in the previous year\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e1\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e1\u003c/p\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003eICU admission during the preceding 6 months\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e1\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e1\u003c/p\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003eIncision cleanness 2–4\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e1\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e1\u003c/p\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003eIntraoperative hypothermia\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e1\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e1\u003c/p\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003eOpen fracture\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e1\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e1\u003c/p\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003ePeripheral vascular disease\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e1\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e1\u003c/p\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003ePostoperative ICU stay (days)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e1\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e1\u003c/p\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003ePreoperative open wound/infection\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e1\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e1\u003c/p\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003ePrevious coronary artery bypass graft surgery\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e1\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e1\u003c/p\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003ePrevious surgery\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e1\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e1\u003c/p\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003ePrior operation on same joint\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e1\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e1\u003c/p\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003eRe-admission to the CVICU\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e1\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e1\u003c/p\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003eRevision or primary surgery\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e1\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e1\u003c/p\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003eSpinal level of surgery\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e1\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e1\u003c/p\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003eSurgery involving the sacrum or pelvis\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e1\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e1\u003c/p\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003eType of surgery procedure\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e1\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e1\u003c/p\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003eUse of antibiotic prophylaxis\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e \u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e \u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e1\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e \u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e1\u003c/p\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003c/tbody\u003e\u003c/table\u003e\n\u003cp/\u003e\n\u003cp class=\"caption\"\u003e\u003ca name=\"_Ref2069642\"/\u003eTable 7: Digestive system univariate analysis preoperative and operative characteristic for the future occurrence of SSI\u003c/p\u003e\n\u003ctable class=table\u003e\u003ctbody\u003e\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003eCharacteristic\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003eSSI = Yes\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003eSSI = No\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003eUnivariate OR (95%CI, p-value)\u003c/p\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003eGender\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003eFemale\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e433 (42.9)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e40 (37.7)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003eMale\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e577 (57.1)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e66 (62.3)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e1.24 (0.82-1.88, p=0.309)\u003c/p\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003eAge\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003e23\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e310 (30.7)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e9 (8.5)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003e23\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e700 (69.3)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e97 (91.5)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e4.77 (2.51-10.28, p\u0026lt;0.001)\u003c/p\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003eASA class\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003eASA CLASS I\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e140 (13.9)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e6 (5.7)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003eASA CLASS II\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e452 (44.8)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e46 (43.4)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e2.37 (1.07-6.31, p=0.052)\u003c/p\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003eASA CLASS III\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e343 (34.0)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e40 (37.7)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e2.72 (1.21-7.28, p=0.026)\u003c/p\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003eASA CLASS IV\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e75 (7.4)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e14 (13.2)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e4.36 (1.67-12.73, p=0.004)\u003c/p\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003eBMI\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e23.7 (5)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e24.2 (4.4)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e1.02 (0.98-1.06, p=0.286)\u003c/p\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003eAlcohol use\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003eCurrent\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e473 (46.8)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e47 (44.3)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003eNever\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e457 (45.2)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e51 (48.1)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e1.12 (0.74-1.71, p=0.585)\u003c/p\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003ePast\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e80 (7.9)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e8 (7.5)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e1.01 (0.43-2.10, p=0.987)\u003c/p\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003eSmoking\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003eCurrent\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e492 (48.7)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e67 (63.2)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003eNever\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e337 (33.4)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e20 (18.9)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e0.44 (0.25-0.72, p=0.002)\u003c/p\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003ePast\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e181 (17.9)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e19 (17.9)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e0.77 (0.44-1.29, p=0.342)\u003c/p\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003eHeart disease\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003eNo\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e960 (95.0)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e97 (91.5)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003eYes\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e50 (5.0)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e9 (8.5)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e1.78 (0.80-3.57, p=0.126)\u003c/p\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003eLiver disease\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003eNo\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e967 (95.7)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e101 (95.3)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003eYes\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e43 (4.3)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e5 (4.7)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e1.11 (0.38-2.63, p=0.825)\u003c/p\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003eHepatitis\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003eNo\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e980 (97.0)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e105 (99.1)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003eYes\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e30 (3.0)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e1 (0.9)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e0.31 (0.02-1.47, p=0.253)\u003c/p\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003eHyper tension\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003eNo\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e841 (83.3)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e90 (84.9)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003eYes\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e169 (16.7)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e16 (15.1)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e0.88 (0.49-1.50, p=0.666)\u003c/p\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003eDiabetes\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003eNo\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e931 (92.2)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e93 (87.7)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003eYes\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e79 (7.8)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e13 (12.3)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e1.65 (0.85-2.98, p=0.117)\u003c/p\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003eHighest temperature\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003e38\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e647 (64.1)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e28 (26.4)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003e(38,39]\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e243 (24.1)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e40 (37.7)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e3.80 (2.31-6.36, p\u0026lt;0.001)\u003c/p\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003e39\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e120 (11.9)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e38 (35.8)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e7.32 (4.34-12.47, p\u0026lt;0.001)\u003c/p\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003eHighest CRP\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003e164\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e905 (89.6)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e75 (70.8)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003e164\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e105 (10.4)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e31 (29.2)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e3.56 (2.22-5.63, p\u0026lt;0.001)\u003c/p\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003eHighest Leukocyte\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e12.2 (7.4)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e12.2 (7.6)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e1.00 (0.97-1.03, p=0.992)\u003c/p\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003eHighest protein\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003e57\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e321 (31.8)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e53 (50.0)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003e57\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e689 (68.2)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e53 (50.0)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e0.47 (0.31-0.70, p\u0026lt;0.001)\u003c/p\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003eHighest Leukocyte\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e149.8 (128.7)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e138.2 (108.6)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e1.00 (1.00-1.00, p=0.372)\u003c/p\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003eHighest glucose\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003e8.2\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e494 (48.9)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e31 (29.2)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003e8.2\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e516 (51.1)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e75 (70.8)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e2.32 (1.51-3.63, p\u0026lt;0.001)\u003c/p\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003eHighest haemoglobin\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e7.9 (1.3)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e7.9 (1.2)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e1.02 (0.88-1.19, p=0.758)\u003c/p\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003eHighest thrombocyte\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003e225\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e692 (68.5)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e95 (89.6)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003e225\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e318 (31.5)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e11 (10.4)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e0.25 (0.13-0.46, p\u0026lt;0.001)\u003c/p\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003ePreoperative length of stay (days)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e7.2 (26.1)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e10.1 (32.8)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e1.00 (1.00-1.01, p=0.286)\u003c/p\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003eAntibiotic use\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003eNo\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e581 (57.5)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e19 (17.9)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003eYes\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e429 (42.5)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e87 (82.1)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e6.20 (3.80-10.64, p\u0026lt;0.001)\u003c/p\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003eUrgency\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003eElective\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e548 (54.3)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e34 (32.1)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003eEmergency\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e462 (45.7)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e72 (67.9)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e2.51 (1.65-3.89, p\u0026lt;0.001)\u003c/p\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003eDuration of surgery\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003e530\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e971 (96.1)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e89 (84.0)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003e530\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e39 (3.9)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e17 (16.0)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e4.76 (2.53-8.62, p\u0026lt;0.001)\u003c/p\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003c/tbody\u003e\u003c/table\u003e\n\u003cp/\u003e\n\u003cp class=\"caption\"\u003e\u003ca name=\"_Ref2069732\"/\u003eTable 8: Orthopaedic surgical procedures univariate analysis preoperative and operative characteristic for the future occurrence of SSI\u003c/p\u003e\n\u003ctable class=table\u003e\u003ctbody\u003e\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003eCharacteristic\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003eSSI = Yes\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003eSSI = No\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003eUnivariate OR (95%CI, p-value)\u003c/p\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003eGender\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003eFemale\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e404 (42.9)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e10 (35.7)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003eMale\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e537 (57.1)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e18 (64.3)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e1.35 (0.63-3.08, p=0.448)\u003c/p\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003eAge\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e49 (21.4)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e48.4 (18)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e1.00 (0.98-1.02, p=0.880)\u003c/p\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003eASA class\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003eASA CLASS I\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e254 (27.0)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e9 (32.1)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003eASA CLASS II\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e411 (43.7)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e9 (32.1)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e0.62 (0.24-1.60, p=0.314)\u003c/p\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003eASA CLASS III\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e247 (26.2)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e8 (28.6)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e0.91 (0.34-2.43, p=0.856)\u003c/p\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003eASA CLASS IV\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e29 (3.1)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e2 (7.1)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e1.95 (0.29-8.02, p=0.409)\u003c/p\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003eBMI\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e25.8 (5)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e27.2 (4.6)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e1.06 (0.98-1.13, p=0.140)\u003c/p\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003eAlcohol use\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003eCurrent\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e486 (51.6)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e16 (57.1)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003eNever or Past\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e455 (48.4)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e12 (42.9)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e0.80 (0.37-1.70, p=0.567)\u003c/p\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003eSmoking\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003eCurrent\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e379 (40.3)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e12 (42.9)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003eNever\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e325 (34.5)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e11 (39.3)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e1.07 (0.46-2.47, p=0.875)\u003c/p\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003ePast\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e237 (25.2)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e5 (17.9)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e0.67 (0.21-1.82, p=0.451)\u003c/p\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003eHeart disease\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003eNo\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e889 (94.5)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e26 (92.9)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003eYes\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e52 (5.5)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e2 (7.1)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e1.32 (0.21-4.57, p=0.714)\u003c/p\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003eLiver disease\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003eNo\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e914 (97.1)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e27 (96.4)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003eYes\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e27 (2.9)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e1 (3.6)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e1.25 (0.07-6.24, p=0.827)\u003c/p\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003eHyper tension\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003eNo\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e781 (83.0)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e23 (82.1)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003eYes\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e160 (17.0)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e5 (17.9)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e1.06 (0.35-2.62, p=0.906)\u003c/p\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003eDiabetes\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003eNo\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e864 (91.8)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e25 (89.3)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003eYes\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e77 (8.2)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e3 (10.7)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e1.35 (0.32-3.95, p=0.633)\u003c/p\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003eHighest temperature\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003e38\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e747 (79.4)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e15 (53.6)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003e38\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e194 (20.6)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e13 (46.4)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e3.34 (1.54-7.14, p=0.002)\u003c/p\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003eHighest CRP\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003e144\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e883 (93.8)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e20 (71.4)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003e144\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e58 (6.2)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e8 (28.6)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e6.09 (2.44-13.96, p\u0026lt;0.001)\u003c/p\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003eHighest Leukocyte\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003e17.3\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e820 (87.1)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e17 (60.7)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003e17.3\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e121 (12.9)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e11 (39.3)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e4.39 (1.95-9.48, p\u0026lt;0.001)\u003c/p\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003eHighest protein\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e62.2 (10.4)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e59.5 (11)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e0.98 (0.94-1.01, p=0.181)\u003c/p\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003eHighest alkaline phosphatase\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e89.8 (72.3)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e79.6 (40.9)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e1.00 (0.99-1.00, p=0.455)\u003c/p\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003eHighest glucose\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e8.6 (3)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e9.2 (4)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e1.06 (0.94-1.17, p=0.282)\u003c/p\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003eHighest haemoglobin\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e8.1 (1.2)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e7.9 (1.3)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e0.90 (0.65-1.24, p=0.510)\u003c/p\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003eHighest thrombocyte\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e185 (94.2)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e157.8 (90.2)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e1.00 (0.99-1.00, p=0.134)\u003c/p\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003ePreoperative length of stay (days)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003e7\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e853 (90.6)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e16 (57.1)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003e7\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e88 (9.4)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e12 (42.9)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e7.27 (3.27-15.79, p\u0026lt;0.001)\u003c/p\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003eAntibiotic use\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003eNo\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e720 (76.5)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e11 (39.3)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003eYes\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e221 (23.5)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e17 (60.7)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e5.03 (2.35-11.23, p\u0026lt;0.001)\u003c/p\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003eUrgency\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003eElective\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e433 (46.0)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e11 (39.3)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003eEmergency\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e508 (54.0)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e17 (60.7)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e1.32 (0.62-2.93, p=0.483)\u003c/p\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003eDuration of surgery\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e205.4 (111.2)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e199.6 (108.6)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e1.00 (1.00-1.00, p=0.788)\u003c/p\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003c/tbody\u003e\u003c/table\u003e\n\u003cp/\u003e\n\u003cp class=\"caption\"\u003e\u003ca name=\"_Ref2069737\"/\u003e\u003ca name=\"_GoBack\"/\u003eTable 9: Thoracic surgical procedures univariate analysis preoperative and operative characteristic for the future occurrence of SSI\u003c/p\u003e\n\u003ctable class=table\u003e\u003ctbody\u003e\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003eCharacteristic\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003eSSI = Yes\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003eSSI = No\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003eUnivariate OR (95%CI, p-value)\u003c/p\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003eGender\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003eFemale\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e406 (36.0)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e13 (34.2)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003eMale\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e721 (64.0)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e25 (65.8)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e1.08 (0.56-2.20, p=0.819)\u003c/p\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003eAge\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003e17\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e246 (21.8)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e17 (44.7)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003e17\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e881 (78.2)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e21 (55.3)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e0.34 (0.18-0.67, p=0.001)\u003c/p\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003eASA class\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003eASA CLASS II\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e212 (18.8)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e5 (13.2)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003eASA CLASS III\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e649 (57.6)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e20 (52.6)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e1.31 (0.52-3.96, p=0.597)\u003c/p\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003eASA CLASS IV\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e266 (23.6)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e13 (34.2)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e2.07 (0.77-6.54, p=0.173)\u003c/p\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003eBMI\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e24.9 (5.1)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e24.1 (4.8)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e0.97 (0.91-1.03, p=0.323)\u003c/p\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003eAlcohol use\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003eCurrent\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e743 (65.9)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e26 (68.4)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003eNever\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e333 (29.5)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e8 (21.1)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e0.69 (0.29-1.47, p=0.359)\u003c/p\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003ePast\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e51 (4.5)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e4 (10.5)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e2.24 (0.64-6.03, p=0.147)\u003c/p\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003eSmoking\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003eCurrent\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e525 (46.6)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e22 (57.9)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003eNever\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e316 (28.0)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e13 (34.2)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e0.98 (0.48-1.95, p=0.959)\u003c/p\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003ePast\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e286 (25.4)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e3 (7.9)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e0.25 (0.06-0.73, p=0.025)\u003c/p\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003eHyper tension\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003eNo\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e818 (72.6)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e29 (76.3)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003eYes\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e309 (27.4)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e9 (23.7)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e0.82 (0.36-1.69, p=0.612)\u003c/p\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003eDiabetes\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003eNo\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e1012 (89.8)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e33 (86.8)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003eYes\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e115 (10.2)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e5 (13.2)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e1.33 (0.45-3.20, p=0.557)\u003c/p\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003eHighest temperature\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003e37\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e316 (28.0)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e2 (5.3)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003e(37,38]\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e612 (54.3)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e20 (52.6)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e5.16 (1.50-32.47, p=0.027)\u003c/p\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003e38\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e199 (17.7)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e16 (42.1)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e12.70 (3.56-80.90, p=0.001)\u003c/p\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003eHighest CRP\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e30.5 (60)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e40.6 (61.6)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e1.00 (1.00-1.01, p=0.313)\u003c/p\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003eHighest Leukocyte\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e11.2 (6.6)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e12 (6.2)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e1.02 (0.97-1.06, p=0.470)\u003c/p\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003eHighest protein\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e65.6 (9.5)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e65.4 (9.7)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e1.00 (0.97-1.03, p=0.865)\u003c/p\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003eHighest alkaline phosphatase\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e92.1 (86.1)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e114.1 (114.7)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e1.00 (1.00-1.00, p=0.134)\u003c/p\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003eHighest glucose\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e10.3 (3.2)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e10.5 (2.8)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e1.02 (0.92-1.12, p=0.684)\u003c/p\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003eHighest haemoglobin\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e8.3 (1.1)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e8.2 (1.4)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e0.97 (0.72-1.28, p=0.814)\u003c/p\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003eHighest thrombocyte\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e243.3 (102.5)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e233 (110.8)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e1.00 (1.00-1.00, p=0.545)\u003c/p\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003ePreoperative length of stay (days)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e6.4 (21.9)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e5.5 (11.1)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e1.00 (0.97-1.01, p=0.806)\u003c/p\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003eAntibiotic use\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003eNo\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e750 (66.5)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e19 (50.0)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003eYes\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e377 (33.5)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e19 (50.0)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e1.99 (1.04-3.82, p=0.037)\u003c/p\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003eUrgency\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003eElective\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e605 (53.7)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e14 (36.8)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp/\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003eEmergency\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e522 (46.3)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e24 (63.2)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e1.99 (1.03-3.98, p=0.044)\u003c/p\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003ctr\u003e\t\u003ctd\u003e\u003cp\u003eDuration of surgery\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e291.6 (126.7)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e270.1 (156.2)\u003c/p\u003e\n\u003c/td\u003e\t\u003ctd\u003e\u003cp\u003e1.00 (1.00-1.00, p=0.307)\u003c/p\u003e\n\u003c/td\u003e\u003c/tr\u003e\n\u003c/tbody\u003e\u003c/table\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":true,"highlight":"","institution":"","isAcceptedByJournal":false,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true},"keywords":"Surgical Wound Infection; Risk Factors; Digestive System Surgical Procedures; Thoracic Surgery; Orthopaedic Procedures","lastPublishedDoi":"10.21203/rs.2.9189/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.2.9189/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003eBackground: To identify common risk factors for the future occurrence of SSI across digestive system surgical procedures, thoracic surgery and orthopaedic procedures and quantify what the marginal contribution of explaining the future occurrence of SSI is of risk factors specific to each group of surgeries. Methods: Retrospective data from serial point-prevalence studies, performed at the Erasmus MC University Medical Center, Rotterdam, The Netherlands were used, together with medical data, from 3.250 surgical procedures, during the period January 2013 to 29 June 2014. Common risk factors across three groups of surgical procedures were identified by scanning literature and univariate analysis. A multivariate forward-step logistic regression model was used to identify the marginal contribution of the risk factor specific to each group of surgical procedure using the increase in the Gini coefficient. Results: For digestive system surgical procedures, antibiotic use, temperature, smoking status, age, CRP, thrombocyte, during of surgery and surgical urgency are risk factors for SSI, where the last four were specific to the digestive system group of surgical procedures and increased the Gini coefficient by 9.5% (0.63 to 0.69). Preoperative length of stay, antibiotic use and Leukocyte are risk factors for orthopaedic surgical procedures. Temperature, age and the use of antibiotics were significant for thoracic surgical procedures. Conclusion: ASA class, body mass index (BMI), Preoperative length of stay, diabetes, antibiotic use, age, Leukocyte, temperature and smoking status as general risk factors common to digestive, orthopaedic and thoracic surgical procedures using existing literature and univariate logistic regression. Risk factors for SSI, specific to a surgical procedure group can increase the ability to explain the future occurrence of SSI by 9.5%. The models developed in this study can aid healthcare workers to improve preoperative counselling and help identify potentially modifiable risk factors.\u003c/p\u003e","manuscriptTitle":"Risk factor identification and contribution to surgery-specific surgical site infection","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2019-04-15 19:35:26","doi":"10.21203/rs.2.9189/v1","editorialEvents":[{"type":"communityComments","content":0}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"610acac0-6321-4cc9-83b4-b1be239c2f4a","owner":[],"postedDate":"April 15th, 2019","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"posted","subjectAreas":[{"id":11363,"name":"Internal Medicine Specialties"}],"tags":[],"updatedAt":"","versionOfRecord":[],"versionCreatedAt":"2019-04-15 19:35:26","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-619","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"identity":"rs-619","version":["v1"]},"buildId":"cBFmMYwuxLRRLfASyISRj","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}