Climatic and Clinical Risk Factors for Surgical Site Infection Following Spine Fusion Surgery: A Large-Scale Big Data Analysis

Climatic and Clinical Risk Factors for Surgical Site Infection Following Spine Fusion Surgery: A Large-Scale Big Data Analysis | 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 Climatic and Clinical Risk Factors for Surgical Site Infection Following Spine Fusion Surgery: A Large-Scale Big Data Analysis Myung-Sup Ko, Soyeong Park, Young-Hoon Kim, Yohan Ko, Kee-Yong Ha, and 4 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-7002924/v1 This work is licensed under a CC BY 4.0 License Status: Published Journal Publication published 10 Jan, 2026 Read the published version in European Spine Journal → Version 1 posted 10 You are reading this latest preprint version Abstract Purpose This study aimed to identify both clinical and meteorological risk factors for surgical site infection (SSI) following spine fusion surgery (SFS), with a focus on integrating medical big data and weather data. Methods We retrospectively analyzed data from 10,880 patients who underwent SFS between January 2013 and November 2022 at eight university-affiliated hospitals. Clinical data were sourced from the Catholic Medical Center Clinical Data Warehouse, and regional meteorological data were obtained from the Korea Meteorological Administration. SSI was defined based on diagnostic codes and antibiotic prescriptions within three months postoperatively. Risk factors were assessed using logistic regression and correlation analyses. Results The overall SSI incidence was 4.66% (507 cases). Significant clinical risk factors included older age, severe obesity (BMI ≥ 35), longer operative time, and higher intraoperative transfusion volume. Surgeries conducted on Wednesdays were associated with a lower SSI risk. While seasonal variation was not statistically significant, SSIs were relatively less common in January and February. Climatic factors, including higher average temperature and humidity during the first postoperative week, were moderately correlated with increased SSI risk (temperature r = 0.51; humidity r = 0.65, both p < 0.01). Maximum daily temperatures above 30°C significantly increased SSI risk (OR = 2.03, p = 0.03). Conclusion This large-scale study is the first to integrate clinical and climatic big data in assessing SSI risk after SFS. In addition to established clinical factors, environmental conditions such as temperature and humidity were shown to influence infection risk. These findings suggest that weather-related factors should be considered in perioperative infection control strategies. Further prospective studies are needed to validate these results and guide clinical practice. surgical site infection spine fusion surgery risk factor climate big data Figures Figure 1 Figure 2 Figure 3 Introduction Surgical site infection (SSI) is one of the most common complications that can occur in the early postoperative period.[ 1 ] SSI remains a significant concern among spine surgery patients due to its associated morbidity, mortality, prolonged hospital length of stay, and increased healthcare costs. The incidence of SSI, including both superficial and deep infections, has been reported to range from 0.2–16.7%.[ 2 – 6 ] Several previous studies have identified various risk factors for SSI following spine surgery, including diabetes, obesity, prolonged operative time, smoking, a history of previous SSI, greater intraoperative blood loss, the number of instrumented levels, and the type of surgical approach used.[ 7 – 12 ] Additionally, recent studies have suggested a potential association between SSI following spine surgery and climatic or seasonal factors, indicating that these environmental factors may contribute to an increased risk of infection.[ 13 – 17 ]. Furthermore, some studies have reported that the occurrence of SSI after spine surgery is influenced by preoperative low calcium levels, high HbA1c, and preoperative and postoperative low albumin levels, as well as postoperative low hemoglobin[ 18 – 20 ]. Although numerous studies have investigated risk factors for SSI following spine surgery, many have been constrained by small sample sizes, and only a limited number have specifically focused on spine fusion surgery (SFS). Moreover, comprehensive risk factor analyses integrating clinical big data with meteorological big data remain scarce. Although some studies have evaluated the impact of seasonal variation and warm climates on the incidence SSIs following spine surgery, no research has specifically investigated how individual climatic parameter such as temperature, humidity, and precipitation correlate with the occurrence of SSIs following SFS, or to what extent they contribute to increased infection risk. Therefore, in this study, we aim to conduct a comprehensive risk factor analysis of SSI following SFS, particularly focusing on SSIs occurring in the early postoperative period. Additionally, we will investigate the correlation between SSI and temporal as well as climatic factors. Materials and methods This study was approved by the institutional review board(IRB) of Seoul Saint Mary’s Hospital (Approval No. : KC23WIDI0767). All data were retrospectively extracted from the Catholic Medical Center’s big data repository, the Clinical Data Warehouse (CDW) system, which integrates data from eight university-affiliated hospitals. We identified all cervical, thoracic, and lumbar fusion surgeries performed in the Departments of Orthopedic Surgery and Neurosurgery across these 8 hospitals between January 2013 and November 2022. Cohort selection : inclusion and exclusion criteria We established a cohort of patients who underwent SFS by utilizing the Electronic Data Interchange(EDI) codes applied for insurance claims under the Korean Health Insurance Review and Assessment Service. Cervical arthrodesis was identified using EDI codes N2461 ~ N2463 and N2467 ~ N2469, while thoracolumbar arthrodesis was identified using EDI codes N0446, N0447, N0466, N0468, N0469, N1460, N1466, N2464 ~ N2466, and N2470. Patients included in this study underwent surgery between January 2013, and November 2022. The following exclusion criteria were applied: Patients who underwent spine fusion surgery due to infective spondylitis Immunocompromised patients (excluding those with diabetes), including those with hematologic malignancies, liver cirrhosis, or HIV infection Patients who had taken specific antibiotics within one month before surgery Operational definition of SSI In this study, we defined SSI occurring within 3 months postoperatively using the following 2 operational criteria ; 1. Diagnosis-based definition Patients who received a diagnostic code for postoperative infection within three months after surgery, based on the Korean Standard Classification of Diseases(KCD) codes (T814, T845, M4650–M4659, M4639–M4649). While this criterion strongly suggests a definitive SSI, it is known that KCD codes for postoperative infections are not always consistently recorded in clinical practice. 2. Antibiotic-based definition Patients who received specific antibiotics commonly used to treat post-operative SSIs(vancomycin, teicoplanin, cefazolin, ampicillin/sulbactam, nafcillin, or rifampin) between three weeks and three months postoperatively. Given that empiric postoperative antibiotics are generally discontinued within one week after surgery, the use of these specific antibiotics beyond three weeks postoperatively in the field of spinal surgery was considered indicative of SSI. Extraction of meteorological big data To analyze the correlation between climate factors and SSI following SFS, as well as to identify climate-related risk factors for SSI, meteorological data were obtained from the Korea Meteorological Administration’s Open MET data portal ( https://data.kma.go.kr/resources/html/en/ncdci.html ). Climate-related parameters were extracted at both daily and hourly intervals. Outcome Parameters The following parameters were assessed: Patient demographics : Gender, age, residential address (limited to city, county, and district level), height, body weight, and body mass index (BMI). Surgery-related parameters : Date of surgery, duration of surgery, volume of intra-operative blood transfusion, and total number of participating surgeons(including the primary and assisting surgeons). Climate-related parameters : Using Open MET data, we extracted daily average temperature, daily maximum temperature, daily average humidity, and daily precipitation. These data were collected for the day of surgery, for one week postoperatively. The hourly temperature and humidity data from Open MET was averaged over 24 hours to define the daily average temperature and humidity. Meteorological data were matched to the patient's hospital location during hospitalization and to their residential address after discharge. Statistical analysis Demographic parameters were compared between the uninfected group and the SSI group using the chi-square test. Logistic regression analysis was also performed to identify potential risk factors for SSI. Additionally, Correlation analysis and logistic regression analysis were conducted to examine the association between climate-related parameters and SSI rates. We examined the relationship between temperature/humidity and SSI occurrence by Pearson’s correlation analysis. All statistical analyses were performed using R software (version 4.3.1), and a p-value of < 0.05 was considered statistically significant. Results From January 2013 to November 2022, a total of 10,880 SFS were performed at our institution. According to two operational definitions, 507 patients developed SSI following SFS within three months after SFS, resulting in an incidence rate of 4.66% (507 of 10,880). Surgery-related factor analysis As shown in Table 1 , patients who underwent SFS in their 50s had a significantly lower risk compared to those in their 60s, whereas the risk increased for those in their 70s and 80s. Patients with severe obesity (BMI ≥ 35.0) had a significantly higher risk of SSI, being 2.06 times more likely to develop an SSI than those within the normal BMI range(≥ 18.5, < 25.0). Additionally, the longer the surgery duration, the higher the risk of SSI. An increased volume of packed red cell transfusion during surgery was also associated with a higher SSI risk. Particularly, patients who received more than 10 packs of packed red cells had a 4.02 times higher risk of SSI compared to those who did not receive a transfusion. Table 1 Demographics and surgery related parameters Parameters Uninfected group n = 10373(95.34%) SSI group n = 507(4.66%) Odds ratio (95% CI) p-value Sex(male) 4737 259 (5.18%) 1.24(1.04–1.49) 0.04 Age < 50 1288 57 (4.24%) 1.00(0.73–1.37) 0.99 50–59 2014 65 (3.13%) 0.73(0.54–0.98) 0.04 60–69 3148 139 (4.23%) Ref 70–79 3175 183 (5.45%) 1.30(1.04–1.63) 0.02 ≥ 80 748 63 (7.77%) 1.91(1.40–2.59) < 0.01 BMI (kg/m2 ) < 18.5 145 3 (2.03%) 0.46(0.14–1.45) 0.18 ≥ 18.5, <25.0 4608 207 (4.30%) Ref ≥ 25.0, <30.0 4548 241 (5.03%) 1.18(0.98–1.43) 0.09 ≥ 30.0, <35.0 932 43 (4.41%) 1.03(0.73–1.44) 0.88 ≥ 35 140 13 (8.50%) 2.06(1.15–3.70) 0.02 Duration of surgery (minutes) < 120 1988 57 (2.79%) Ref 120–180 3423 101 (2.87%) 1.03(0.74–1.43) 0.87 180–240 2584 141 (5.17%) 1.90(1.39–2.60) < 0.01 240–300 1280 82 (6.02%) 2.24(1.58–3.16) < 0.01 ≥ 300 1098 126 (10.29%) 4.00(2.90–5.52) < 0.01 Participating surgeons 1–2 5633 267 (4.53%) Ref ≥ 3 4740 240 (4.82%) 1.07(0.89–1.28) 0.47 Amount of transfusion(PRC) 0 6161 203 (3.19%) Ref 1–5 3213 199 (5.83%) 1.88(1.54–2.30) < 0.01 6–10 493 38 (7.16%) 2.34(1.64–3.35) < 0.01 ≥ 10 506 67 (11.69%) 4.02(3.01–5.37) < 0.01 BMI = body mass index CI = confidence interval Ref = reference PRC = packed red cells Temporal and seasonal factor analysis Given that South Korea has distinct four seasons with significant annual temperature variations, we analyzed whether temporal and seasonal factors influence the occurrence of SSI after SFS. As shown in Table 2 , there was no significant difference in SSI risk among the four seasons. When analyzing the risk of SSI by month, the odds ratio for January was 0.66(0.41–1.04, p-value = 0.08), and for February, it was 0.62(0.38–1.02, p-value = 0.06), compared to March as the baseline, indicating a lower but not statistically significant risk. Regarding the day of the week, compared to Monday as the baseline, the risk of SSI was significantly lower on Wednesdays(odds ratio = 0.67(0.50–0.99), p-value < 0.01). Table 2 Temporal and seasonal factor analysis Parameters Uninfected group n = 10373(95.34%) SSI group n = 507(4.66%) Odds ratio (95% CI) p-value Season Spring 2495 128(4.88%) 1.13(0.88–1.47) 0.34 Summer 2668 131(4.68%) 1.09(0.84–1.40) 0.53 Fall 2624 131(4.75%) 1.10(0.85–1.42) 0.45 Winter 2586 117(4.33%) Ref Month January 900 32(3.43%) 0.66(0.41–1.04) 0.08 February 768 26(3.27%) 0.62(0.38–1.02) 0.06 March 829 45(5.15%) Ref April 899 42(4.46%) 0.86(0.56–1.32) 0.49 May 767 41(5.07%) 0.98(0.64–1.52) 0.94 June 885 47(5.04%) 0.98(0.64–1.49) 0.92 July 911 47(4.91%) 0.95(0.63–1.45) 0.82 August 872 37(4.07%) 0.78(0.50–1.22) 0.28 September 796 43(5.13%) 1.00(0.65–1.53) 0.98 October 876 53(5.71%) 1.11(0.74–1.68) 0.61 November 952 35(3.55%) 0.68(0.43–1.06) 0.09 December 918 59(6.04%) 1.18(0.80–1.77) 0.41 Day of the week Monday 1915 109(5.39%) Ref Tuesday 1994 92(4.41%) 0.81(0.61–1.08) 0.15 Wednesday 2507 95(3.65%) 0.67(0.50–0.88) < 0.01 Thursday 1641 88(5.09%) 0.94(0.71–1.26) 0.68 Friday 2215 112(4.81%) 0.89(0.68–1.16) 0.39 Saturday 82 7(7.87%) Sunday 19 4(17.39%) CI = confidence interval Ref = reference Climatic factor analysis To examine the correlation between climate factors and SSI occurrence after SFS, we integrated clinical data extracted from the CDW system with meteorological data obtained from Open MET, South Korea's climate big data platform provided by the Korea Meteorological Administration. We analyzed the correlation between SSI occurrence and: (a) the daily average temperature on the day of surgery (Fig. 1 a) ; (b) the 7-day average daily temperature post-surgery (Fig. 1 b), and ; (c) the 30-day average daily temperature post-surgery (Fig. 1 c). Notably, the 7-day average daily temperature showed a moderate correlation with SSI rate(correlation coefficient = 0.5, p-value < 0.01). Similarly, we examined the daily maximum temperature on the day of surgery (Fig. 2 a), the 7-day average daily maximum temperature (Fig. 2 b), and the 30-day average daily maximum temperature (Fig. 2 c), finding that the 7-day average daily maximum temperature had a moderate correlation with SSI incidence (correlation coefficient = 0.56, p-value < 0.01). We also analyzed the relationship between SSI incidence and: (a) the daily average humidity on the day of surgery (Fig. 3 a) ; (b) the 7-day average daily humidity post-surgery (Fig. 3 b) ; and (c) the 30-day average daily humidity post-surgery (Fig. 3 c). Notably, the 7-day average daily humidity showed a high correlation with SSI incidence (correlation coefficient = 0.65, p-value < 0.01). Next, we analyzed the risk factors for SSI after SFS using climate data. Temperature was categorized into 5°C intervals, ranging from below − 10°C to above 30°C, and logistic regression analysis was performed for both daily average temperature and daily maximum temperature (Table 3 ). As shown in Table 3 a, there was no temperature range that showed a statistically significant change in the odds ratio for SSI based on the daily average temperature on the day of surgery or the 7-day average postoperatively. However, a general trend of increasing odds ratio with rising temperature was observed. In Table 3 b, an overall increasing trend in odds ratio with rising daily maximum temperature was identified. Specifically, compared to the baseline range of -5°C to 0°C, the risk of SSI was significantly higher in the 20°C to 25°C range (odds ratio = 1.95(1.03–3.69), p-value = 0.04) and in the above 30°C range (odds ratio = 2.03(1.06–3.86,) p-value = 0.03). Table 3 SSI risk analysis by temperature range using logistic regression Uninfected group n = 10373(95.34%) SSI group n = 507(4.66%) Odds ratio (95% CI) p-value a. Daily average temperature (°C) The day of surgery < -10 55 3(5.17%) 1.42(0.43–4.71) 0.57 ≥ -10 < -5 362 11(2.95%) 0.68(0.34–1.37) 0.28 ≥ -5, < 0 1039 44(4.06%) Ref ≥ 0, < 5 1366 73(5.07%) 1.31(0.89–1.93) 0.17 ≥ 5, < 10 1265 64(4.82%) 1.21(0.81–1.79) 0.35 ≥ 10, < 15 1537 65(4.06%) 1.02(0.69–1.50) 0.94 ≥ 15, < 20 1212 72(5.61%) 1.43(0.97–2.10) 0.07 ≥ 20, < 25 2130 99(4.44%) 1.09(0.75–1.57) 0.66 ≥ 25, < 30 1304 69(5.03%) 1.32(0.90–1.94) 0.16 ≥ 30 103 7(6.36%) 1.57(0.69–3.57) 0.29 Until 1 week after surgery < -10 5 0 ≥ -10 < -5 174 7(3.87%) 1.01(0.45–2.27) 0.98 ≥ -5, < 0 1164 46(3.80%) Ref ≥ 0, < 5 1544 77(4.75%) 1.25(0.86–1.81) 0.25 ≥ 5, < 10 1238 62(4.77%) 1.26(0.85–1.86) 0.25 ≥ 10, < 15 1479 80(5.13%) 1.36(0.94–1.97) 0.10 ≥ 15, < 20 1174 55(4.48%) 1.16(0.77–1.72) 0.48 ≥ 20, < 25 2344 114(4.64%) 1.23(0.87–1.75) 0.24 ≥ 25, < 30 1164 61(4.98%) 1.32(0.89–1.94) 0.17 ≥ 30 87 5(5.43%) 1.45(0.56–3.74) 0.44 b. Daily maximum temperature (°C) The day of surgery < -10 9 1(10.00%) 4.45(.050-39.69) 0.18 ≥ -10 < -5 77 5(6.10%) 2.82(0.96–8.33) 0.06 ≥ -5, < 0 415 12(2.81%) Ref ≥ 0, < 5 1093 47(4.12%) 1.63(0.84–3.16) 0.15 ≥ 5, < 10 1341 69(4.89%) 1.86(0.98–3.55) 0.06 ≥ 10, < 15 1085 54(4.74%) 1.86(0.97–3.55) 0.06 ≥ 15, < 20 1436 69(4.58%) 1.73(0.91–3.29) 0.10 ≥ 20, < 25 1521 83(5.17%) 1.95(1.03–3.69) 0.04 ≥ 25, < 30 2217 101(4.36%) 1.73(0.92–3.24) 0.09 ≥ 30 1179 66(5.30%) 2.03(1.06–3.86) 0.03 Until 1 week after surgery < -10 0 0 ≥ -10 < -5 16 0 ≥ -5, < 0 250 9(3.47%) Ref ≥ 0, < 5 1236 50(3.89%) 1.11(0.54–2.30) 0.77 ≥ 5, < 10 1427 72(4.80%) 1.39(0.69–2.82) 0.36 ≥ 10, < 15 1057 52(4.69%) 1.36(0.66–2.79) 0.41 ≥ 15, < 20 1440 78(5.14%) 1.50(0.74–3.02) 0.26 ≥ 20, < 25 1361 61(4.29%) 1.21(0.59–2.48) 0.60 ≥ 25, < 30 2654 132(4.74%) 1.38(0.70–2.74) 0.36 ≥ 30 932 53(5.38%) 1.56(0.76–3.19) 0.23 Ref = reference Similarly, as shown in Table 4 , daily average humidity was categorized into 10% intervals, ranging from below 30% to above 90%, to analyze its association with SSI risk. Although no specific humidity range showed a statistically significant difference, when the daily average humidity exceeded 90% on the day of surgery, the risk of SSI was 1.43 times higher than in the baseline range of 30–40% (odds ratio = 1.43(0.85–2.40,) p-value = 0.18). Table 4 SSI risk analysis by humidity range using logistic regression Uninfected group n = 10373(95.34%) SSI group n = 507(4.66%) Odds ratio (95% CI) p-value Daily average humidity(%) The day of surgery < 30 86 2(2.27%) 0.48(0.11–2.03) 0.32 ≥ 30 < 40 507 26(4.88%) Ref ≥ 40, < 50 1485 72(4.62%) 0.95(0.60–1.51) 0.84 ≥ 50, < 60 2192 101(4.40%) 0.89(0.57–1.39) 0.62 ≥ 60, < 70 2447 128(4.97%) 1.05(0.68–1.61) 0.84 ≥ 70, < 80 2059 94(4.37%) 0.88(0.57–1.38) 0.58 ≥ 80, < 90 1097 47(4.11%) 0.85(0.52–1.39) 0.52 ≥ 90 500 37(6.89%) 1.43(0.85–2.40) 0.18 Until 1 week after surgery < 30 0 0 ≥ 30 < 40 105 4(3.67%) Ref ≥ 40, < 50 859 42(4.66%) 1.30(0.45–3.71) 0.63 ≥ 50, < 60 2889 119(3.96%) 1.01(0.40–3.03) 0.86 ≥ 60, < 70 3334 173(4.93%) 1.38(0.50–3.80) 0.54 ≥ 70, < 80 2269 123(5.14%) 1.44(0.52–3.99) 0.49 ≥ 80, < 90 799 40(4.77%) 1.33(0.46–3.80) 0.60 ≥ 90 115 6(4.96%) 1.39(0.38–5.01) 0.62 Ref = reference Finally, precipitation was analyzed as a potential risk factor by dividing it into three groups: 0 mm, 0–10 mm, and above 10 mm. However, no significant association between precipitation and SSI risk was found (Table 5 ). Table 5 SSI risk analysis by daily precipitation range using logistic regression Uninfected group n = 10373(95.34%) SSI group n = 507(4.66%) Odds ratio (95% CI) p-value Daily precipitation(mm) The day of surgery 0 7333 363(4.72%) Ref ≥ 0, < 10 2195 103(4.48%) 0.95(0.76–1.19) 0.66 ≥ 10 845 41(4.63%) 0.98(0.70–1.36) 0.89 *Until 1 week after surgery 0 1815 80(4.22%) Ref ≥ 0, < 10 7700 386(4.77%) 1.14(0.89–1.46) 0.30 ≥ 10 858 41(4.56%) 1.09(0.74–1.59) 0.68 Ref = reference * average of the daily precipitation for the 7 days after the day of surgery Discussion There have been several studies analyzing the risk factors for SSI following spinal surgeries. However, this study is the first large-scale analysis of risk factors for SSI specifically after SFS, a type of spinal surgery where infections can be severe. This study particularly focused on how temporal, seasonal, and climatic factors influence the occurrence of SSI after SFS in a large patient cohort. Previous studies have reported that warmer temperatures and warmer seasons can increase the risk of SSI[ 21 – 25 ]. However, analyzing climatic factors has been challenging due to variations in the timing of surgery, the hospital addresses where patients were admitted, and the addresses of their residences post-discharge. These factors make it difficult to conduct large-scale studies tailored to individual patients. In our study, we combined clinical data with weather data provided by the Korea Meteorological Administration, allowing for an analysis of climate factors on a large cohort of patients. Additionally, we divided temperature and humidity into different ranges to assess whether increases in these factors contributed to the higher risk of SSI. As shown in Table 1 , the risk factors related to surgery were consistent with previously reported findings[ 26 – 32 ]. The risk of SSI increased with age, and particularly for patients with a BMI greater than 35, the risk was elevated. The risk of SSI also increased as the duration of the surgery lengthened, but the number of surgeons involved did not significantly affect the risk. While prior studies have suggested that warmer seasons increase the risk of SSI[ 16 , 17 , 21 , 22 , 25 ], this study did not find that seasonal changes in South Korea had a significant effect on SSI risk. However, monthly analysis showed that, although not statistically significant, January and February had relatively lower rates of SSI following SFS. This could be attributed to South Korea's unique climate and its medical training system. As reported in previous studies, SSI risk is generally lower during colder weather, and in South Korea, the medical training system ends in February. This may result in higher levels of experience and proficiency among attending surgeons, interns, and residents involved in both the surgeries and postoperative care during this time, contributing to a lower risk of SSI. In the analysis of SSI risk by the day of the week, surgeries performed on Wednesdays showed a lower risk of SSI. Since Wednesday is the middle weekday, this may allow more time for both preoperative and postoperative care during working days, reducing the risk of infection. Although not directly related to SSI, a study reported that mortality rates are higher when nonemergent major surgery is performed on a Friday compared to Monday through Wednesday[ 33 ]. This finding suggests that the day of the week on which SFS is performed may also significantly influence the SSI rate. In this study, we also analyzed whether objective climatic indicators such as temperature and humidity had a correlation with the occurrence of SSI following SFS. We hypothesized that not only the weather on the day of surgery, but also the climate during the postoperative care period (one week and one month post-surgery), might have a relationship with the occurrence of SSI. Figure 1 shows a correlation coefficient of 0.51 for the average daily temperature during the first week following surgery, and Fig. 2 shows a correlation coefficient of 0.56 for the daily maximum temperature. These moderate correlations indicate that rising temperatures are associated with an increase in the SSI rate. Additionally, as shown in Fig. 3 , there was a significant correlation of 0.65 between the daily average humidity and the occurrence of SSI during the first week post-surgery, proving a notable correlation between temperature, humidity, and the incidence of SSI after SFS. We also conducted an analysis to examine whether changes in temperature, humidity, and precipitation could be risk factors for SSI following SFS. As shown in Table 3 , an increase in temperature generally led to an increase in the odds ratio. Specifically, when the daily maximum temperature on the day of surgery exceeded 30°C, the odds ratio for SSI was approximately twice as high as when the temperature was between − 5°C and 0°C, indicating a significantly increased risk of SSI following SFS in warmer conditions. Previous big data analyses of SSI risk for surgeries in other surgical fields also reported an increase in the odds ratio with rising temperatures[ 34 ]. Although the trend in this study was irregular, it confirmed that increasing temperature generally raises the risk of SSI after SFS. In the analysis of humidity as a risk factor, no significant difference in the odds ratio was found across humidity ranges. However, in climates with humidity levels above 90%, a slight increase in the odds ratio was observed. While some previous studies have reported that high humidity increases the risk of SSI[ 35 ], and others have suggested that intraoperative humidity has no significant impact[ 36 ], no study to date has specifically investigated the effect of humidity on SSI following SFS. In this study, we demonstrated that a high humidity may contribute to an increased risk of SSI after SFS Rising temperature and humidity could potentially worsen hygiene conditions for patients post-surgery, increasing the risk of infection. Moreover, high temperature and humidity can cause psychological stress in both humans and animals, leading to dysregulation of the hypothalamic-pituitary-adrenal axis and increased cortisol levels, which could result in decreased immune function, contributing to an increased risk of infection post-surgery[ 37 – 40 ]. This study reaffirmed that known factors such as age, BMI, duration of surgery, and amount of transfusion contribute to the risk of SSI following spine fusion surgery. While seasonal variability in SSI risk did not reach statistical significance, the finding that the risk of infection was relatively lower in the coldest months of January and February suggests that colder weather may contribute to reducing the risk of infection post-surgery. This is the first study to analyze the risk of SSI after SFS using large-scale clinical and climatic big data. However, there are several limitations. First, as this study was retrospective, we were limited to relying solely on medical records. Second, the operative definition of postoperative infection was incomplete. Due to the retrospective nature, we had to rely on records, and there were cases where data on postoperative SSI, such as diagnostic codes, were missing. We had to infer infection based on antibiotic use, which might explain the higher postoperative SSI rate compared to previous studies. In this study, we applied different weather data based on the patient's hospital address during admission and their residential address after discharge. However, this assumption that patients stayed at their homes after discharge may introduce errors. In conclusion, as previously reported, age, obesity, prolonged surgery time, and the amount of transfusion contribute to the risk of SSI following SFS. Temporal and seasonal analysis showed that the risk of SSI was relatively lower during the colder months of January and February, and weekday analysis indicated that surgeries performed on Wednesdays had a significantly lower risk of infection. This study focused particularly on the correlation between climate factors and SSI risk following SFS, showing that average daily maximum temperature and daily average humidity during the first week post-surgery were significantly correlated with the incidence of SSI. Moreover, temperature and humidity increases were identified as risk factors for SSI. Further analysis of additional climatic factors related to the occurrence of SSI is warranted in future studies. Declarations Author Contribution Myung-Sup Ko, Sang-Il Kim, Young-Hoon Kim and Kee-Yong Ha contributed to the study conception and design. Material preparation, data collection and analysis were performed by Myung-Sup Ko, Soyeong Park, Yohan Ko, Hyung-Youl Park, and Yunseong Kim. The first draft of the manuscript was written by Myung-Sup Ko, Soyeong Park and Young-Hoon Kim. The overall supervision of this project was done by Yohan Ko and Sang-Il Kim. All authors commented on previous versions of the manuscript. All authors read and approved the final manuscript. Data Availability The datasets generated during the current study are available from the corresponding author on reasonable request. References Horan TC, Culver DH, Gaynes RP, Jarvis WR, Edwards JR, Reid CR (1993) Nosocomial infections in surgical patients in the United States, January 1986-June 1992. National Nosocomial Infections Surveillance (NNIS) System. Infect Control Hosp Epidemiol 14:73-80. doi: 10.1086/646686 Fei Q, Li J, Lin J, Li D, Wang B, Meng H, Wang Q, Su N, Yang Y (2016) Risk Factors for Surgical Site Infection After Spinal Surgery: A Meta-Analysis. World Neurosurg 95:507-515. doi: 10.1016/j.wneu.2015.05.059 Pull ter Gunne AF, Cohen DB (2009) Incidence, prevalence, and analysis of risk factors for surgical site infection following adult spinal surgery. Spine (Phila Pa 1976) 34:1422-1428. doi: 10.1097/BRS.0b013e3181a03013 Kim JH, Ahn DK, Kim JW, Kim GW (2015) Particular Features of Surgical Site Infection in Posterior Lumbar Interbody Fusion. Clin Orthop Surg 7:337-343. doi: 10.4055/cios.2015.7.3.337 Ramo BA, Roberts DW, Tuason D, McClung A, Paraison LE, Moore HGt, Sucato DJ (2014) Surgical site infections after posterior spinal fusion for neuromuscular scoliosis: a thirty-year experience at a single institution. J Bone Joint Surg Am 96:2038-2048. doi: 10.2106/jbjs.N.00277 Schimmel JJ, Horsting PP, de Kleuver M, Wonders G, van Limbeek J (2010) Risk factors for deep surgical site infections after spinal fusion. Eur Spine J 19:1711-1719. doi: 10.1007/s00586-010-1421-y Patel N, Bagan B, Vadera S, Maltenfort MG, Deutsch H, Vaccaro AR, Harrop J, Sharan A, Ratliff JK (2007) Obesity and spine surgery: relation to perioperative complications. J Neurosurg Spine 6:291-297. doi: 10.3171/spi.2007.6.4.1 Fang A, Hu SS, Endres N, Bradford DS (2005) Risk factors for infection after spinal surgery. Spine (Phila Pa 1976) 30:1460-1465. doi: 10.1097/01.brs.0000166532.58227.4f Cizik AM, Lee MJ, Martin BI, Bransford RJ, Bellabarba C, Chapman JR, Mirza SK (2012) Using the spine surgical invasiveness index to identify risk of surgical site infection: a multivariate analysis. J Bone Joint Surg Am 94:335-342. doi: 10.2106/jbjs.J.01084 Olsen MA, Nepple JJ, Riew KD, Lenke LG, Bridwell KH, Mayfield J, Fraser VJ (2008) Risk factors for surgical site infection following orthopaedic spinal operations. J Bone Joint Surg Am 90:62-69. doi: 10.2106/jbjs.F.01515 Ho C, Sucato DJ, Richards BS (2007) Risk factors for the development of delayed infections following posterior spinal fusion and instrumentation in adolescent idiopathic scoliosis patients. Spine (Phila Pa 1976) 32:2272-2277. doi: 10.1097/BRS.0b013e31814b1c0b Kurtz SM, Lau E, Ong KL, Carreon L, Watson H, Albert T, Glassman S (2012) Infection risk for primary and revision instrumented lumbar spine fusion in the Medicare population. J Neurosurg Spine 17:342-347. doi: 10.3171/2012.7.Spine12203 Chehrassan M, Nikouei F, Shakeri M, Behnamnia A, Mahabadi EA, Ghandhari H (2024) The role of environmental and seasonal factors in spine deep surgical site infection: the air pollution, a factor that may be underestimated. Eur Spine J 33:3148-3153. doi: 10.1007/s00586-024-08183-z Sahtoe APH, Duraku LS, van der Oest MJW, Hundepool CA, de Kraker M, Bode LGM, Zuidam JM (2021) Warm Weather and Surgical Site Infections: A Meta-analysis. Plastic and Reconstructive Surgery – Global Open 9:e3705. doi: 10.1097/gox.0000000000003705 Durkin MJ, Dicks KV, Baker AW, Moehring RW, Chen LF, Sexton DJ, Lewis SS, Anderson DJ (2015) Postoperative infection in spine surgery: does the month matter? Journal of Neurosurgery: Spine 23:128-134 Shuman WH, Baron RB, Gal JS, Li AY, Neifert SN, Hannah TC, Dreher N, Schupper AJ, Steinberger JM, Caridi JM (2022) Seasonal effects on surgical site infections following spine surgery. World Neurosurgery 161:e174-e182 Sahtoe AP, Duraku LS, van der Oest MJ, Hundepool CA, de Kraker M, Bode LG, Zuidam JM (2021) Warm weather and surgical site infections: a meta-analysis. Plastic and Reconstructive Surgery–Global Open 9:e3705 Salvetti DJ, Tempel ZJ, Goldschmidt E, Colwell NA, Angriman F, Panczykowski DM, Agarwal N, Kanter AS, Okonkwo DO (2018) Low preoperative serum prealbumin levels and the postoperative surgical site infection risk in elective spine surgery: a consecutive series. J Neurosurg Spine 29:549-552. doi: 10.3171/2018.3.Spine171183 Liu JM, Deng HL, Chen XY, Zhou Y, Yang D, Duan MS, Huang SH, Liu ZL (2018) Risk Factors for Surgical Site Infection After Posterior Lumbar Spinal Surgery. Spine (Phila Pa 1976) 43:732-737. doi: 10.1097/brs.0000000000002419 Hara H, Kanayama M, Oha F, Shimamura Y, Watanabe T, Hashimoto T, Kawasaki T, Ishijima M (2024) Effect of pre-operative HbA1c and blood glucose level on the surgical site infection after lumbar instrumentation surgery. J Orthop Sci 29:1168-1173. doi: 10.1016/j.jos.2023.08.015 Gruskay J, Smith J, Kepler CK, Radcliff K, Harrop J, Albert T, Vaccaro A (2013) The seasonality of postoperative infection in spine surgery. J Neurosurg Spine 18:57-62. doi: 10.3171/2012.10.Spine12572 Anthony CA, Peterson RA, Polgreen LA, Sewell DK, Polgreen PM (2017) The Seasonal Variability in Surgical Site Infections and the Association With Warmer Weather: A Population-Based Investigation. Infect Control Hosp Epidemiol 38:809-816. doi: 10.1017/ice.2017.84 Shuman WH, Baron RB, Gal JS, Li AY, Neifert SN, Hannah TC, Dreher N, Schupper AJ, Steinberger JM, Caridi JM, Choudhri TF (2022) Seasonal Effects on Surgical Site Infections Following Spine Surgery. World Neurosurg 161:e174-e182. doi: 10.1016/j.wneu.2022.01.100 Sahtoe APH, Duraku LS, van der Oest MJW, Hundepool CA, de Kraker M, Bode LGM, Zuidam JM (2021) Warm Weather and Surgical Site Infections: A Meta-analysis. Plast Reconstr Surg Glob Open 9:e3705. doi: 10.1097/gox.0000000000003705 Ogawa T, Yoshii T, Morishita S, Moriwaki M, Okawa A, Nazarian A, Fushimi K, Fujiwara T (2021) Seasonal impact on surgical site infections in hip fracture surgery: Analysis of 330,803 cases using a nationwide inpatient database. Injury 52:898-904. doi: 10.1016/j.injury.2020.10.058 Zhang X, Liu P, You J (2022) Risk factors for surgical site infection following spinal surgery: a meta-analysis. Medicine 101:e28836 Fei Q, Li J, Lin J, Li D, Wang B, Meng H, Wang Q, Su N, Yang Y (2016) Risk factors for surgical site infection after spinal surgery: a meta-analysis. World neurosurgery 95:507-515 Yao R, Zhou H, Choma TJ, Kwon BK, Street J (2018) Surgical site infection in spine surgery: who is at risk? Global spine journal 8:5S-30S Olsen MA, Mayfield J, Lauryssen C, Polish LB, Jones M, Vest J, Fraser VJ (2003) Risk factors for surgical site infection in spinal surgery. Journal of Neurosurgery: Spine 98:149-155 Meng F, Cao J, Meng X (2015) Risk factors for surgical site infections following spinal surgery. Journal of Clinical Neuroscience 22:1862-1866 Ter Gunne AFP, Cohen DB (2009) Incidence, prevalence, and analysis of risk factors for surgical site infection following adult spinal surgery. Spine 34:1422-1428 Olsen MA, Nepple JJ, Riew KD, Lenke LG, Bridwell KH, Mayfield J, Fraser VJ (2008) Risk factors for surgical site infection following orthopaedic spinal operations. JBJS 90:62-69 Zare MM, Itani KM, Schifftner TL, Henderson WG, Khuri SF (2007) Mortality after nonemergent major surgery performed on Friday versus Monday through Wednesday. Ann Surg 246:866-874. doi: 10.1097/SLA.0b013e3180cc2e60 Anthony CA, Peterson RA, Polgreen LA, Sewell DK, Polgreen PM (2017) The seasonal variability in surgical site infections and the association with warmer weather: a population-based investigation. infection control & hospital epidemiology 38:809-816 Alfonso-Sanchez JL, Martinez IM, Martín-Moreno JM, González RS, Botía F (2017) Analyzing the risk factors influencing surgical site infections: the site of environmental factors. Can J Surg 60:155-161. doi: 10.1503/cjs.017916 Hammond JB, Madura GM, Chang YH, Lim ES, Habermann E, Cima R, Colibaseanu D, Siebeneck ET, Etzioni DA (2023) The influence of operating room temperature and humidity on surgical site infection: A multisite ACS-NSQIP analysis. Am J Surg 226:840-844. doi: 10.1016/j.amjsurg.2023.06.039 Awad R, Suberry A, Abu-Akel A, Ayalon L (2025) Heat stress effects on the immune system of older adults: A systematic literature review. Experimental Gerontology:112777 Giaretta E, Mongillo P, Da Dalt L, Gianesella M, Bortoletti M, Degano L, Vicario D, Gabai G (2023) Temperature and humidity index (THI) affects salivary cortisol (HC) and dehydroepiandrosterone (DHEA) concentrations in growing bulls following stress generated by performance test procedures. Frontiers in Veterinary Science 10:1237634 Zhang X, Hu S, Guo C, Liu R, Tong L, Shi B, Li B (2023) Association between thermal comfort and cortisol depends on the air temperature and exposure time. Building and Environment 233:110073 Yang M, Luo Y, Hao XZ, Guo MY, Li W, Hu YH (2021) Effects of high temperature and high humidity stress on the negative feedback regulation of hippocampus on HPA axis in rats. Neuro Endocrinol Lett 42:312-320 Additional Declarations No competing interests reported. Cite Share Download PDF Status: Published Journal Publication published 10 Jan, 2026 Read the published version in European Spine Journal → Version 1 posted Editorial decision: Revision requested 17 Sep, 2025 Reviews received at journal 07 Aug, 2025 Reviews received at journal 31 Jul, 2025 Reviewers agreed at journal 14 Jul, 2025 Reviewers agreed at journal 12 Jul, 2025 Reviewers agreed at journal 11 Jul, 2025 Reviewers invited by journal 10 Jul, 2025 Editor assigned by journal 03 Jul, 2025 Submission checks completed at journal 03 Jul, 2025 First submitted to journal 29 Jun, 2025 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-7002924","acceptedTermsAndConditions":true,"allowDirectSubmit":false,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":484517265,"identity":"4b10ba91-add5-4e97-8f36-fc201602ea24","order_by":0,"name":"Myung-Sup Ko","email":"","orcid":"","institution":"Seoul St. Mary's Hospital, College of Medicine, The Catholic University of Korea","correspondingAuthor":false,"prefix":"","firstName":"Myung-Sup","middleName":"","lastName":"Ko","suffix":""},{"id":484517266,"identity":"0889e571-ba3d-464d-8bc9-ee9d8d27e42f","order_by":1,"name":"Soyeong Park","email":"","orcid":"","institution":"Yonsei 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16:09:31","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":2868847,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-7002924/v1/3e5b223a-4d8b-412e-8300-912da849c9d0.pdf"}],"financialInterests":"No competing interests reported.","formattedTitle":"Climatic and Clinical Risk Factors for Surgical Site Infection Following Spine Fusion Surgery: A Large-Scale Big Data Analysis","fulltext":[{"header":"Introduction","content":"\u003cp\u003eSurgical site infection (SSI) is one of the most common complications that can occur in the early postoperative period.[\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e] SSI remains a significant concern among spine surgery patients due to its associated morbidity, mortality, prolonged hospital length of stay, and increased healthcare costs. The incidence of SSI, including both superficial and deep infections, has been reported to range from 0.2\u0026ndash;16.7%.[\u003cspan additionalcitationids=\"CR3 CR4 CR5\" citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e]\u003c/p\u003e\u003cp\u003eSeveral previous studies have identified various risk factors for SSI following spine surgery, including diabetes, obesity, prolonged operative time, smoking, a history of previous SSI, greater intraoperative blood loss, the number of instrumented levels, and the type of surgical approach used.[\u003cspan additionalcitationids=\"CR8 CR9 CR10 CR11\" citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e] Additionally, recent studies have suggested a potential association between SSI following spine surgery and climatic or seasonal factors, indicating that these environmental factors may contribute to an increased risk of infection.[\u003cspan additionalcitationids=\"CR14 CR15 CR16\" citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e17\u003c/span\u003e]. Furthermore, some studies have reported that the occurrence of SSI after spine surgery is influenced by preoperative low calcium levels, high HbA1c, and preoperative and postoperative low albumin levels, as well as postoperative low hemoglobin[\u003cspan additionalcitationids=\"CR19\" citationid=\"CR18\" class=\"CitationRef\"\u003e18\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR20\" class=\"CitationRef\"\u003e20\u003c/span\u003e].\u003c/p\u003e\u003cp\u003eAlthough numerous studies have investigated risk factors for SSI following spine surgery, many have been constrained by small sample sizes, and only a limited number have specifically focused on spine fusion surgery (SFS). Moreover, comprehensive risk factor analyses integrating clinical big data with meteorological big data remain scarce. Although some studies have evaluated the impact of seasonal variation and warm climates on the incidence SSIs following spine surgery, no research has specifically investigated how individual climatic parameter such as temperature, humidity, and precipitation correlate with the occurrence of SSIs following SFS, or to what extent they contribute to increased infection risk.\u003c/p\u003e\u003cp\u003eTherefore, in this study, we aim to conduct a comprehensive risk factor analysis of SSI following SFS, particularly focusing on SSIs occurring in the early postoperative period. Additionally, we will investigate the correlation between SSI and temporal as well as climatic factors.\u003c/p\u003e"},{"header":"Materials and methods","content":"\u003cp\u003e This study was approved by the institutional review board(IRB) of Seoul Saint Mary\u0026rsquo;s Hospital (Approval No. : KC23WIDI0767). All data were retrospectively extracted from the Catholic Medical Center\u0026rsquo;s big data repository, the Clinical Data Warehouse (CDW) system, which integrates data from eight university-affiliated hospitals. We identified all cervical, thoracic, and lumbar fusion surgeries performed in the Departments of Orthopedic Surgery and Neurosurgery across these 8 hospitals between January 2013 and November 2022.\u003c/p\u003e\u003cdiv id=\"Sec3\" class=\"Section2\"\u003e\u003ch2\u003eCohort selection : inclusion and exclusion criteria\u003c/h2\u003e\u003cp\u003eWe established a cohort of patients who underwent SFS by utilizing the Electronic Data Interchange(EDI) codes applied for insurance claims under the Korean Health Insurance Review and Assessment Service. Cervical arthrodesis was identified using EDI codes N2461\u0026thinsp;~\u0026thinsp;N2463 and N2467\u0026thinsp;~\u0026thinsp;N2469, while thoracolumbar arthrodesis was identified using EDI codes N0446, N0447, N0466, N0468, N0469, N1460, N1466, N2464\u0026thinsp;~\u0026thinsp;N2466, and N2470. Patients included in this study underwent surgery between January 2013, and November 2022.\u003c/p\u003e\u003cp\u003eThe following exclusion criteria were applied:\u003c/p\u003e\u003cp\u003e\u003cul\u003e\u003cli\u003e\u003cp\u003ePatients who underwent spine fusion surgery due to infective spondylitis\u003c/p\u003e\u003c/li\u003e\u003cli\u003e\u003cp\u003eImmunocompromised patients (excluding those with diabetes), including those with hematologic malignancies, liver cirrhosis, or HIV infection\u003c/p\u003e\u003c/li\u003e\u003cli\u003e\u003cp\u003ePatients who had taken specific antibiotics within one month before surgery\u003c/p\u003e\u003c/li\u003e\u003c/ul\u003e\u003c/p\u003e\u003c/div\u003e\n\u003ch3\u003eOperational definition of SSI\u003c/h3\u003e\n\u003cp\u003eIn this study, we defined SSI occurring within 3 months postoperatively using the following 2 operational criteria ;\u003c/p\u003e\u003cp\u003e1. Diagnosis-based definition\u003c/p\u003e\n\u003cp\u003ePatients who received a diagnostic code for postoperative infection within three months after surgery, based on the Korean Standard Classification of Diseases(KCD) codes (T814, T845, M4650\u0026ndash;M4659, M4639\u0026ndash;M4649). While this criterion strongly suggests a definitive SSI, it is known that KCD codes for postoperative infections are not always consistently recorded in clinical practice.\u003c/p\u003e\n\u003cp\u003e\u003cspan\u003e2. Antibiotic-based definition\u003cbr\u003e\u003c/span\u003e\u003cspan\u003ePatients who received specific antibiotics commonly used to treat post-operative SSIs(vancomycin, teicoplanin, cefazolin, ampicillin/sulbactam, nafcillin, or rifampin) between three weeks and three months postoperatively. Given that empiric postoperative antibiotics are generally discontinued within one week after surgery, the use of these specific antibiotics beyond three weeks postoperatively in the field of spinal surgery was considered indicative of SSI.\u003cbr\u003e\u003c/span\u003e\u003c/p\u003e\n\u003ch3\u003eExtraction of meteorological big data\u003c/h3\u003e\n\u003cp\u003eTo analyze the correlation between climate factors and SSI following SFS, as well as to identify climate-related risk factors for SSI, meteorological data were obtained from the Korea Meteorological Administration\u0026rsquo;s Open MET data portal (\u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://data.kma.go.kr/resources/html/en/ncdci.html\u003c/span\u003e\u003c/span\u003e).\u003c/p\u003e\n\u003cp\u003eClimate-related parameters were extracted at both daily and hourly intervals.\u003c/p\u003e\n\u003ch3\u003eOutcome Parameters\u003c/h3\u003e\n\u003cp\u003eThe following parameters were assessed:\u003c/p\u003e\n\u003cul\u003e\n \u003cli\u003e\n \u003cp\u003ePatient demographics :\u003c/p\u003e\n \u003c/li\u003e\n \u003cli\u003e\n \u003cp\u003eGender, age, residential address (limited to city, county, and district level), height, body weight, and body mass index (BMI).\u003c/p\u003e\n \u003c/li\u003e\n \u003cli\u003e\n \u003cp\u003eSurgery-related parameters :\u003c/p\u003e\n \u003c/li\u003e\n \u003cli\u003e\n \u003cp\u003eDate of surgery, duration of surgery, volume of intra-operative blood transfusion, and total number of participating surgeons(including the primary and assisting surgeons).\u003c/p\u003e\n \u003c/li\u003e\n \u003cli\u003e\n \u003cp\u003eClimate-related parameters :\u003c/p\u003e\n \u003c/li\u003e\n \u003cli\u003e\n \u003cp\u003eUsing Open MET data, we extracted daily average temperature, daily maximum temperature, daily average humidity, and daily precipitation. These data were collected for the day of surgery, for one week postoperatively. The hourly temperature and humidity data from Open MET was averaged over 24 hours to define the daily average temperature and humidity. Meteorological data were matched to the patient\u0026apos;s hospital location during hospitalization and to their residential address after discharge.\u003c/p\u003e\u003cbr\u003e\n \u003c/li\u003e\n\u003c/ul\u003e\n\u003cdiv id=\"Sec7\" class=\"Section2\"\u003e\n \u003ch2\u003eStatistical analysis\u003c/h2\u003e\n \u003cp\u003eDemographic parameters were compared between the uninfected group and the SSI group using the chi-square test. Logistic regression analysis was also performed to identify potential risk factors for SSI. Additionally, Correlation analysis and logistic regression analysis were conducted to examine the association between climate-related parameters and SSI rates. We examined the relationship between temperature/humidity and SSI occurrence by Pearson\u0026rsquo;s correlation analysis. All statistical analyses were performed using R software (version 4.3.1), and a p-value of \u0026lt;\u0026thinsp;0.05 was considered statistically significant.\u003c/p\u003e\n\u003c/div\u003e"},{"header":"Results","content":"\u003cp\u003eFrom January 2013 to November 2022, a total of 10,880 SFS were performed at our institution. According to two operational definitions, 507 patients developed SSI following SFS within three months after SFS, resulting in an incidence rate of 4.66% (507 of 10,880).\u003c/p\u003e\n\u003ch3\u003eSurgery-related factor analysis\u003c/h3\u003e\n\u003cp\u003eAs shown in Table\u0026nbsp;\u003cspan refid=\"Tab1\" class=\"InternalRef\"\u003e1\u003c/span\u003e, patients who underwent SFS in their 50s had a significantly lower risk compared to those in their 60s, whereas the risk increased for those in their 70s and 80s. Patients with severe obesity (BMI\u0026thinsp;\u0026ge;\u0026thinsp;35.0) had a significantly higher risk of SSI, being 2.06 times more likely to develop an SSI than those within the normal BMI range(\u0026ge;\u0026thinsp;18.5, \u0026lt;\u0026thinsp;25.0). Additionally, the longer the surgery duration, the higher the risk of SSI. An increased volume of packed red cell transfusion during surgery was also associated with a higher SSI risk. Particularly, patients who received more than 10 packs of packed red cells had a 4.02 times higher risk of SSI compared to those who did not receive a transfusion.\u003c/p\u003e\u003cp\u003e\u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab1\" border=\"1\"\u003e\u003ccaption language=\"En\"\u003e\u003cdiv class=\"CaptionNumber\"\u003eTable 1\u003c/div\u003e\u003cdiv class=\"CaptionContent\"\u003e\u003cp\u003e Demographics and surgery related parameters\u003c/p\u003e\u003c/div\u003e\u003c/caption\u003e\u003ccolgroup cols=\"5\"\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c5\" colnum=\"5\"\u003e\u003c/div\u003e\u003cthead\u003e\u003ctr\u003e\u003cth align=\"left\" colname=\"c1\"\u003e\u003cp\u003eParameters\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c2\"\u003e\u003cp\u003eUninfected group\u003c/p\u003e\u003cp\u003en\u0026thinsp;=\u0026thinsp;10373(95.34%)\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c3\"\u003e\u003cp\u003eSSI group\u003c/p\u003e\u003cp\u003en\u0026thinsp;=\u0026thinsp;507(4.66%)\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c4\"\u003e\u003cp\u003eOdds ratio\u003c/p\u003e\u003cp\u003e(95% CI)\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c5\"\u003e\u003cp\u003ep-value\u003c/p\u003e\u003c/th\u003e\u003c/tr\u003e\u003c/thead\u003e\u003ctbody\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e\u003cb\u003eSex(male)\u003c/b\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e4737\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e259 (5.18%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e1.24(1.04\u0026ndash;1.49)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e\u003cb\u003e0.04\u003c/b\u003e\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e\u003cb\u003eAge\u003c/b\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e\u0026lt;\u0026thinsp;50\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e1288\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e57 (4.24%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e1.00(0.73\u0026ndash;1.37)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e0.99\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e50\u0026ndash;59\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e2014\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e65 (3.13%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e0.73(0.54\u0026ndash;0.98)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e\u003cb\u003e0.04\u003c/b\u003e\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e60\u0026ndash;69\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e3148\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e139 (4.23%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003eRef\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e70\u0026ndash;79\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e3175\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e183 (5.45%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e1.30(1.04\u0026ndash;1.63)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e\u003cb\u003e0.02\u003c/b\u003e\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e\u0026ge;\u0026thinsp;80\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e748\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e63 (7.77%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e1.91(1.40\u0026ndash;2.59)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e\u003cb\u003e\u0026lt;\u0026thinsp;0.01\u003c/b\u003e\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e\u003cb\u003eBMI (kg/m2\u003c/b\u003e)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e\u0026lt;\u0026thinsp;18.5\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e145\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e3 (2.03%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e0.46(0.14\u0026ndash;1.45)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e0.18\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e\u0026ge;\u0026thinsp;18.5, \u0026lt;25.0\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e4608\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e207 (4.30%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003eRef\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e\u0026ge;\u0026thinsp;25.0, \u0026lt;30.0\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e4548\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e241 (5.03%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e1.18(0.98\u0026ndash;1.43)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e0.09\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e\u0026ge;\u0026thinsp;30.0, \u0026lt;35.0\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e932\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e43 (4.41%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e1.03(0.73\u0026ndash;1.44)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e0.88\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e\u0026ge;\u0026thinsp;35\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e140\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e13 (8.50%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e2.06(1.15\u0026ndash;3.70)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e\u003cb\u003e0.02\u003c/b\u003e\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e\u003cb\u003eDuration of surgery (minutes)\u003c/b\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e\u0026lt;\u0026thinsp;120\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e1988\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e57 (2.79%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003eRef\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e120\u0026ndash;180\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e3423\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e101 (2.87%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e1.03(0.74\u0026ndash;1.43)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e0.87\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e180\u0026ndash;240\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e2584\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e141 (5.17%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e1.90(1.39\u0026ndash;2.60)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e\u003cb\u003e\u0026lt;\u0026thinsp;0.01\u003c/b\u003e\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e240\u0026ndash;300\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e1280\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e82 (6.02%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e2.24(1.58\u0026ndash;3.16)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e\u003cb\u003e\u0026lt;\u0026thinsp;0.01\u003c/b\u003e\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e\u0026ge;\u0026thinsp;300\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e1098\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e126 (10.29%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e4.00(2.90\u0026ndash;5.52)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e\u003cb\u003e\u0026lt;\u0026thinsp;0.01\u003c/b\u003e\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e\u003cb\u003eParticipating surgeons\u003c/b\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e1\u0026ndash;2\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e5633\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e267 (4.53%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003eRef\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e\u0026ge;\u0026thinsp;3\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e4740\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e240 (4.82%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e1.07(0.89\u0026ndash;1.28)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e0.47\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e\u003cb\u003eAmount of transfusion(PRC)\u003c/b\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e0\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e6161\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e203 (3.19%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003eRef\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e1\u0026ndash;5\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e3213\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e199 (5.83%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e1.88(1.54\u0026ndash;2.30)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e\u003cb\u003e\u0026lt;\u0026thinsp;0.01\u003c/b\u003e\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e6\u0026ndash;10\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e493\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e38 (7.16%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e2.34(1.64\u0026ndash;3.35)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e\u003cb\u003e\u0026lt;\u0026thinsp;0.01\u003c/b\u003e\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e\u0026ge;\u0026thinsp;10\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e506\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e67 (11.69%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e4.02(3.01\u0026ndash;5.37)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e\u003cb\u003e\u0026lt;\u0026thinsp;0.01\u003c/b\u003e\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colspan=\"5\" nameend=\"c5\" namest=\"c1\"\u003e\u003cp\u003eBMI\u0026thinsp;=\u0026thinsp;body mass index\u003c/p\u003e\u003cp\u003eCI\u0026thinsp;=\u0026thinsp;confidence interval\u003c/p\u003e\u003cp\u003eRef\u0026thinsp;=\u0026thinsp;reference\u003c/p\u003e\u003cp\u003ePRC\u0026thinsp;=\u0026thinsp;packed red cells\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003c/tbody\u003e\u003c/colgroup\u003e\u003c/table\u003e\u003c/div\u003e\u003c/p\u003e\n\u003ch3\u003eTemporal and seasonal factor analysis\u003c/h3\u003e\n\u003cp\u003eGiven that South Korea has distinct four seasons with significant annual temperature variations, we analyzed whether temporal and seasonal factors influence the occurrence of SSI after SFS. As shown in Table\u0026nbsp;\u003cspan refid=\"Tab2\" class=\"InternalRef\"\u003e2\u003c/span\u003e, there was no significant difference in SSI risk among the four seasons. When analyzing the risk of SSI by month, the odds ratio for January was 0.66(0.41\u0026ndash;1.04, p-value\u0026thinsp;=\u0026thinsp;0.08), and for February, it was 0.62(0.38\u0026ndash;1.02, p-value\u0026thinsp;=\u0026thinsp;0.06), compared to March as the baseline, indicating a lower but not statistically significant risk. Regarding the day of the week, compared to Monday as the baseline, the risk of SSI was significantly lower on Wednesdays(odds ratio\u0026thinsp;=\u0026thinsp;0.67(0.50\u0026ndash;0.99), p-value\u0026thinsp;\u0026lt;\u0026thinsp;0.01).\u003c/p\u003e\u003cp\u003e\u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab2\" border=\"1\"\u003e\u003ccaption language=\"En\"\u003e\u003cdiv class=\"CaptionNumber\"\u003eTable 2\u003c/div\u003e\u003cdiv class=\"CaptionContent\"\u003e\u003cp\u003e Temporal and seasonal factor analysis\u003c/p\u003e\u003c/div\u003e\u003c/caption\u003e\u003ccolgroup cols=\"5\"\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c5\" colnum=\"5\"\u003e\u003c/div\u003e\u003cthead\u003e\u003ctr\u003e\u003cth align=\"left\" colname=\"c1\"\u003e\u003cp\u003eParameters\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c2\"\u003e\u003cp\u003eUninfected group\u003c/p\u003e\u003cp\u003en\u0026thinsp;=\u0026thinsp;10373(95.34%)\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c3\"\u003e\u003cp\u003eSSI group\u003c/p\u003e\u003cp\u003en\u0026thinsp;=\u0026thinsp;507(4.66%)\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c4\"\u003e\u003cp\u003eOdds ratio\u003c/p\u003e\u003cp\u003e(95% CI)\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c5\"\u003e\u003cp\u003ep-value\u003c/p\u003e\u003c/th\u003e\u003c/tr\u003e\u003ctr\u003e\u003cth align=\"left\" colname=\"c1\"\u003e\u003cp\u003eSeason\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/th\u003e\u003cth align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/th\u003e\u003cth align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/th\u003e\u003cth align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/th\u003e\u003c/tr\u003e\u003c/thead\u003e\u003ctbody\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eSpring\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e2495\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e128(4.88%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e1.13(0.88\u0026ndash;1.47)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e0.34\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eSummer\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e2668\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e131(4.68%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e1.09(0.84\u0026ndash;1.40)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e0.53\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eFall\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e2624\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e131(4.75%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e1.10(0.85\u0026ndash;1.42)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e0.45\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eWinter\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e2586\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e117(4.33%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003eRef\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e\u003cb\u003eMonth\u003c/b\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eJanuary\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e900\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e32(3.43%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e0.66(0.41\u0026ndash;1.04)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e0.08\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eFebruary\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e768\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e26(3.27%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e0.62(0.38\u0026ndash;1.02)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e0.06\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eMarch\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e829\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e45(5.15%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003eRef\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eApril\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e899\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e42(4.46%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e0.86(0.56\u0026ndash;1.32)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e0.49\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eMay\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e767\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e41(5.07%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e0.98(0.64\u0026ndash;1.52)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e0.94\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eJune\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e885\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e47(5.04%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e0.98(0.64\u0026ndash;1.49)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e0.92\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eJuly\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e911\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e47(4.91%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e0.95(0.63\u0026ndash;1.45)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e0.82\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eAugust\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e872\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e37(4.07%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e0.78(0.50\u0026ndash;1.22)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e0.28\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eSeptember\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e796\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e43(5.13%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e1.00(0.65\u0026ndash;1.53)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e0.98\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eOctober\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e876\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e53(5.71%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e1.11(0.74\u0026ndash;1.68)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e0.61\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eNovember\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e952\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e35(3.55%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e0.68(0.43\u0026ndash;1.06)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e0.09\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eDecember\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e918\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e59(6.04%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e1.18(0.80\u0026ndash;1.77)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e0.41\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e\u003cb\u003eDay of the week\u003c/b\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eMonday\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e1915\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e109(5.39%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003eRef\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eTuesday\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e1994\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e92(4.41%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e0.81(0.61\u0026ndash;1.08)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e0.15\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eWednesday\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e2507\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e95(3.65%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e0.67(0.50\u0026ndash;0.88)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e\u003cb\u003e\u0026lt;\u0026thinsp;0.01\u003c/b\u003e\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eThursday\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e1641\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e88(5.09%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e0.94(0.71\u0026ndash;1.26)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e0.68\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eFriday\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e2215\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e112(4.81%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e0.89(0.68\u0026ndash;1.16)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e0.39\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eSaturday\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e82\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e7(7.87%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eSunday\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e19\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e4(17.39%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colspan=\"5\" nameend=\"c5\" namest=\"c1\"\u003e\u003cp\u003eCI\u0026thinsp;=\u0026thinsp;confidence interval\u003c/p\u003e\u003cp\u003eRef\u0026thinsp;=\u0026thinsp;reference\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003c/tbody\u003e\u003c/colgroup\u003e\u003c/table\u003e\u003c/div\u003e\u003c/p\u003e\u003cdiv id=\"Sec11\" class=\"Section2\"\u003e\u003ch2\u003eClimatic factor analysis\u003c/h2\u003e\u003cp\u003eTo examine the correlation between climate factors and SSI occurrence after SFS, we integrated clinical data extracted from the CDW system with meteorological data obtained from Open MET, South Korea's climate big data platform provided by the Korea Meteorological Administration.\u003c/p\u003e\u003cp\u003eWe analyzed the correlation between SSI occurrence and: (a) the daily average temperature on the day of surgery (Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003ea) ; (b) the 7-day average daily temperature post-surgery (Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003eb), and ; (c) the 30-day average daily temperature post-surgery (Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003ec). Notably, the 7-day average daily temperature showed a moderate correlation with SSI rate(correlation coefficient\u0026thinsp;=\u0026thinsp;0.5, p-value\u0026thinsp;\u0026lt;\u0026thinsp;0.01). Similarly, we examined the daily maximum temperature on the day of surgery (Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003ea), the 7-day average daily maximum temperature (Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003eb), and the 30-day average daily maximum temperature (Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003ec), finding that the 7-day average daily maximum temperature had a moderate correlation with SSI incidence (correlation coefficient\u0026thinsp;=\u0026thinsp;0.56, p-value\u0026thinsp;\u0026lt;\u0026thinsp;0.01).\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\u003cp\u003eWe also analyzed the relationship between SSI incidence and: (a) the daily average humidity on the day of surgery (Fig.\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003ea) ; (b) the 7-day average daily humidity post-surgery (Fig.\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003eb) ; and (c) the 30-day average daily humidity post-surgery (Fig.\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003ec). Notably, the 7-day average daily humidity showed a high correlation with SSI incidence (correlation coefficient\u0026thinsp;=\u0026thinsp;0.65, p-value\u0026thinsp;\u0026lt;\u0026thinsp;0.01).\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\u003cp\u003eNext, we analyzed the risk factors for SSI after SFS using climate data. Temperature was categorized into 5\u0026deg;C intervals, ranging from below \u0026minus;\u0026thinsp;10\u0026deg;C to above 30\u0026deg;C, and logistic regression analysis was performed for both daily average temperature and daily maximum temperature (Table\u0026nbsp;\u003cspan refid=\"Tab3\" class=\"InternalRef\"\u003e3\u003c/span\u003e). As shown in Table\u0026nbsp;\u003cspan refid=\"Tab3\" class=\"InternalRef\"\u003e3\u003c/span\u003ea, there was no temperature range that showed a statistically significant change in the odds ratio for SSI based on the daily average temperature on the day of surgery or the 7-day average postoperatively. However, a general trend of increasing odds ratio with rising temperature was observed. In Table\u0026nbsp;\u003cspan refid=\"Tab3\" class=\"InternalRef\"\u003e3\u003c/span\u003eb, an overall increasing trend in odds ratio with rising daily maximum temperature was identified. Specifically, compared to the baseline range of -5\u0026deg;C to 0\u0026deg;C, the risk of SSI was significantly higher in the 20\u0026deg;C to 25\u0026deg;C range (odds ratio\u0026thinsp;=\u0026thinsp;1.95(1.03\u0026ndash;3.69), p-value\u0026thinsp;=\u0026thinsp;0.04) and in the above 30\u0026deg;C range (odds ratio\u0026thinsp;=\u0026thinsp;2.03(1.06\u0026ndash;3.86,) p-value\u0026thinsp;=\u0026thinsp;0.03).\u003c/p\u003e\u003cp\u003e\u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab3\" border=\"1\"\u003e\u003ccaption language=\"En\"\u003e\u003cdiv class=\"CaptionNumber\"\u003eTable 3\u003c/div\u003e\u003cdiv class=\"CaptionContent\"\u003e\u003cp\u003e SSI risk analysis by temperature range using logistic regression\u003c/p\u003e\u003c/div\u003e\u003c/caption\u003e\u003ccolgroup cols=\"5\"\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c5\" colnum=\"5\"\u003e\u003c/div\u003e\u003cthead\u003e\u003ctr\u003e\u003cth align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/th\u003e\u003cth align=\"left\" colname=\"c2\"\u003e\u003cp\u003eUninfected group\u003c/p\u003e\u003cp\u003en\u0026thinsp;=\u0026thinsp;10373(95.34%)\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c3\"\u003e\u003cp\u003eSSI group\u003c/p\u003e\u003cp\u003en\u0026thinsp;=\u0026thinsp;507(4.66%)\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c4\"\u003e\u003cp\u003eOdds ratio\u003c/p\u003e\u003cp\u003e(95% CI)\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c5\"\u003e\u003cp\u003ep-value\u003c/p\u003e\u003c/th\u003e\u003c/tr\u003e\u003ctr\u003e\u003cth align=\"left\" colspan=\"5\" nameend=\"c5\" namest=\"c1\"\u003e\u003cp\u003ea. \u003cem\u003eDaily average temperature (\u0026deg;C)\u003c/em\u003e\u003c/p\u003e\u003c/th\u003e\u003c/tr\u003e\u003ctr\u003e\u003cth align=\"left\" colname=\"c1\"\u003e\u003cp\u003eThe day of surgery\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/th\u003e\u003cth align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/th\u003e\u003cth align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/th\u003e\u003cth align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/th\u003e\u003c/tr\u003e\u003c/thead\u003e\u003ctbody\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e\u0026lt; -10\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e55\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e3(5.17%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e1.42(0.43\u0026ndash;4.71)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e0.57\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e\u0026ge; -10 \u0026lt; -5\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e362\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e11(2.95%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e0.68(0.34\u0026ndash;1.37)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e0.28\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e\u0026ge; -5, \u0026lt; 0\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e1039\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e44(4.06%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003eRef\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e\u0026ge;\u0026thinsp;0, \u0026lt; 5\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e1366\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e73(5.07%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e1.31(0.89\u0026ndash;1.93)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e0.17\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e\u0026ge;\u0026thinsp;5, \u0026lt; 10\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e1265\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e64(4.82%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e1.21(0.81\u0026ndash;1.79)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e0.35\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e\u0026ge;\u0026thinsp;10, \u0026lt; 15\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e1537\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e65(4.06%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e1.02(0.69\u0026ndash;1.50)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e0.94\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e\u0026ge;\u0026thinsp;15, \u0026lt; 20\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e1212\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e72(5.61%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e1.43(0.97\u0026ndash;2.10)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e0.07\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e\u0026ge;\u0026thinsp;20, \u0026lt; 25\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e2130\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e99(4.44%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e1.09(0.75\u0026ndash;1.57)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e0.66\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e\u0026ge;\u0026thinsp;25, \u0026lt; 30\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e1304\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e69(5.03%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e1.32(0.90\u0026ndash;1.94)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e0.16\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e\u0026ge;\u0026thinsp;30\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e103\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e7(6.36%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e1.57(0.69\u0026ndash;3.57)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e0.29\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e\u003cb\u003eUntil 1 week after surgery\u003c/b\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e\u0026lt; -10\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e5\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e0\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e\u0026ge; -10 \u0026lt; -5\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e174\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e7(3.87%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e1.01(0.45\u0026ndash;2.27)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e0.98\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e\u0026ge; -5, \u0026lt; 0\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e1164\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e46(3.80%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003eRef\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e\u0026ge;\u0026thinsp;0, \u0026lt; 5\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e1544\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e77(4.75%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e1.25(0.86\u0026ndash;1.81)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e0.25\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e\u0026ge;\u0026thinsp;5, \u0026lt; 10\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e1238\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e62(4.77%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e1.26(0.85\u0026ndash;1.86)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e0.25\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e\u0026ge;\u0026thinsp;10, \u0026lt; 15\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e1479\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e80(5.13%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e1.36(0.94\u0026ndash;1.97)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e0.10\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e\u0026ge;\u0026thinsp;15, \u0026lt; 20\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e1174\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e55(4.48%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e1.16(0.77\u0026ndash;1.72)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e0.48\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e\u0026ge;\u0026thinsp;20, \u0026lt; 25\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e2344\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e114(4.64%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e1.23(0.87\u0026ndash;1.75)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e0.24\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e\u0026ge;\u0026thinsp;25, \u0026lt; 30\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e1164\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e61(4.98%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e1.32(0.89\u0026ndash;1.94)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e0.17\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e\u0026ge;\u0026thinsp;30\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e87\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e5(5.43%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e1.45(0.56\u0026ndash;3.74)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e0.44\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colspan=\"5\" nameend=\"c5\" namest=\"c1\"\u003e\u003cp\u003eb. \u003cb\u003eDaily maximum temperature (\u0026deg;C)\u003c/b\u003e\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e\u003cb\u003eThe day of surgery\u003c/b\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e\u0026lt; -10\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e9\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e1(10.00%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e4.45(.050-39.69)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e0.18\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e\u0026ge; -10 \u0026lt; -5\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e77\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e5(6.10%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e2.82(0.96\u0026ndash;8.33)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e0.06\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e\u0026ge; -5, \u0026lt; 0\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e415\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e12(2.81%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003eRef\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e\u0026ge;\u0026thinsp;0, \u0026lt; 5\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e1093\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e47(4.12%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e1.63(0.84\u0026ndash;3.16)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e0.15\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e\u0026ge;\u0026thinsp;5, \u0026lt; 10\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e1341\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e69(4.89%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e1.86(0.98\u0026ndash;3.55)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e0.06\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e\u0026ge;\u0026thinsp;10, \u0026lt; 15\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e1085\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e54(4.74%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e1.86(0.97\u0026ndash;3.55)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e0.06\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e\u0026ge;\u0026thinsp;15, \u0026lt; 20\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e1436\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e69(4.58%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e1.73(0.91\u0026ndash;3.29)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e0.10\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e\u0026ge;\u0026thinsp;20, \u0026lt; 25\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e1521\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e83(5.17%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e1.95(1.03\u0026ndash;3.69)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e\u003cb\u003e0.04\u003c/b\u003e\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e\u0026ge;\u0026thinsp;25, \u0026lt; 30\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e2217\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e101(4.36%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e1.73(0.92\u0026ndash;3.24)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e0.09\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e\u0026ge;\u0026thinsp;30\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e1179\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e66(5.30%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e2.03(1.06\u0026ndash;3.86)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e\u003cb\u003e0.03\u003c/b\u003e\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e\u003cb\u003eUntil 1 week after surgery\u003c/b\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e\u0026lt; -10\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e0\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e0\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e\u0026ge; -10 \u0026lt; -5\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e16\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e0\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e\u0026ge; -5, \u0026lt; 0\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e250\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e9(3.47%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003eRef\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e\u0026ge;\u0026thinsp;0, \u0026lt; 5\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e1236\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e50(3.89%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e1.11(0.54\u0026ndash;2.30)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e0.77\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e\u0026ge;\u0026thinsp;5, \u0026lt; 10\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e1427\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e72(4.80%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e1.39(0.69\u0026ndash;2.82)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e0.36\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e\u0026ge;\u0026thinsp;10, \u0026lt; 15\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e1057\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e52(4.69%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e1.36(0.66\u0026ndash;2.79)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e0.41\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e\u0026ge;\u0026thinsp;15, \u0026lt; 20\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e1440\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e78(5.14%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e1.50(0.74\u0026ndash;3.02)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e0.26\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e\u0026ge;\u0026thinsp;20, \u0026lt; 25\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e1361\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e61(4.29%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e1.21(0.59\u0026ndash;2.48)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e0.60\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e\u0026ge;\u0026thinsp;25, \u0026lt; 30\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e2654\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e132(4.74%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e1.38(0.70\u0026ndash;2.74)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e0.36\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e\u0026ge;\u0026thinsp;30\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e932\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e53(5.38%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e1.56(0.76\u0026ndash;3.19)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e0.23\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colspan=\"5\" nameend=\"c5\" namest=\"c1\"\u003e\u003cp\u003eRef\u0026thinsp;=\u0026thinsp;reference\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003c/tbody\u003e\u003c/colgroup\u003e\u003c/table\u003e\u003c/div\u003e\u003c/p\u003e\u003cp\u003eSimilarly, as shown in Table\u0026nbsp;\u003cspan refid=\"Tab4\" class=\"InternalRef\"\u003e4\u003c/span\u003e, daily average humidity was categorized into 10% intervals, ranging from below 30% to above 90%, to analyze its association with SSI risk. Although no specific humidity range showed a statistically significant difference, when the daily average humidity exceeded 90% on the day of surgery, the risk of SSI was 1.43 times higher than in the baseline range of 30\u0026ndash;40% (odds ratio\u0026thinsp;=\u0026thinsp;1.43(0.85\u0026ndash;2.40,) p-value\u0026thinsp;=\u0026thinsp;0.18).\u003c/p\u003e\u003cp\u003e\u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab4\" border=\"1\"\u003e\u003ccaption language=\"En\"\u003e\u003cdiv class=\"CaptionNumber\"\u003eTable 4\u003c/div\u003e\u003cdiv class=\"CaptionContent\"\u003e\u003cp\u003e SSI risk analysis by humidity range using logistic regression\u003c/p\u003e\u003c/div\u003e\u003c/caption\u003e\u003ccolgroup cols=\"5\"\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c5\" colnum=\"5\"\u003e\u003c/div\u003e\u003cthead\u003e\u003ctr\u003e\u003cth align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/th\u003e\u003cth align=\"left\" colname=\"c2\"\u003e\u003cp\u003eUninfected group\u003c/p\u003e\u003cp\u003en\u0026thinsp;=\u0026thinsp;10373(95.34%)\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c3\"\u003e\u003cp\u003eSSI group\u003c/p\u003e\u003cp\u003en\u0026thinsp;=\u0026thinsp;507(4.66%)\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c4\"\u003e\u003cp\u003eOdds ratio\u003c/p\u003e\u003cp\u003e(95% CI)\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c5\"\u003e\u003cp\u003ep-value\u003c/p\u003e\u003c/th\u003e\u003c/tr\u003e\u003ctr\u003e\u003cth align=\"left\" colspan=\"5\" nameend=\"c5\" namest=\"c1\"\u003e\u003cp\u003e\u003cem\u003eDaily average humidity(%)\u003c/em\u003e\u003c/p\u003e\u003c/th\u003e\u003c/tr\u003e\u003ctr\u003e\u003cth align=\"left\" colname=\"c1\"\u003e\u003cp\u003eThe day of surgery\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/th\u003e\u003cth align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/th\u003e\u003cth align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/th\u003e\u003cth align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/th\u003e\u003c/tr\u003e\u003c/thead\u003e\u003ctbody\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e\u0026lt;\u0026thinsp;30\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e86\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e2(2.27%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e0.48(0.11\u0026ndash;2.03)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e0.32\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e\u0026ge;\u0026thinsp;30 \u0026lt; 40\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e507\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e26(4.88%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003eRef\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e\u0026ge;\u0026thinsp;40, \u0026lt; 50\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e1485\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e72(4.62%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e0.95(0.60\u0026ndash;1.51)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e0.84\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e\u0026ge;\u0026thinsp;50, \u0026lt; 60\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e2192\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e101(4.40%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e0.89(0.57\u0026ndash;1.39)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e0.62\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e\u0026ge;\u0026thinsp;60, \u0026lt; 70\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e2447\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e128(4.97%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e1.05(0.68\u0026ndash;1.61)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e0.84\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e\u0026ge;\u0026thinsp;70, \u0026lt; 80\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e2059\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e94(4.37%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e0.88(0.57\u0026ndash;1.38)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e0.58\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e\u0026ge;\u0026thinsp;80, \u0026lt; 90\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e1097\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e47(4.11%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e0.85(0.52\u0026ndash;1.39)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e0.52\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e\u0026ge;\u0026thinsp;90\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e500\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e37(6.89%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e1.43(0.85\u0026ndash;2.40)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e0.18\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e\u003cb\u003eUntil 1 week after surgery\u003c/b\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e\u0026lt;\u0026thinsp;30\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e0\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e0\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e\u0026ge;\u0026thinsp;30 \u0026lt; 40\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e105\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e4(3.67%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003eRef\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e\u0026ge;\u0026thinsp;40, \u0026lt; 50\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e859\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e42(4.66%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e1.30(0.45\u0026ndash;3.71)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e0.63\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e\u0026ge;\u0026thinsp;50, \u0026lt; 60\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e2889\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e119(3.96%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e1.01(0.40\u0026ndash;3.03)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e0.86\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e\u0026ge;\u0026thinsp;60, \u0026lt; 70\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e3334\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e173(4.93%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e1.38(0.50\u0026ndash;3.80)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e0.54\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e\u0026ge;\u0026thinsp;70, \u0026lt; 80\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e2269\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e123(5.14%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e1.44(0.52\u0026ndash;3.99)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e0.49\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e\u0026ge;\u0026thinsp;80, \u0026lt; 90\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e799\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e40(4.77%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e1.33(0.46\u0026ndash;3.80)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e0.60\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e\u0026ge;\u0026thinsp;90\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e115\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e6(4.96%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e1.39(0.38\u0026ndash;5.01)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e0.62\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colspan=\"5\" nameend=\"c5\" namest=\"c1\"\u003e\u003cp\u003eRef\u0026thinsp;=\u0026thinsp;reference\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003c/tbody\u003e\u003c/colgroup\u003e\u003c/table\u003e\u003c/div\u003e\u003c/p\u003e\u003cp\u003eFinally, precipitation was analyzed as a potential risk factor by dividing it into three groups: 0 mm, 0\u0026ndash;10 mm, and above 10 mm. However, no significant association between precipitation and SSI risk was found (Table\u0026nbsp;\u003cspan refid=\"Tab5\" class=\"InternalRef\"\u003e5\u003c/span\u003e).\u003c/p\u003e\u003cp\u003e\u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab5\" border=\"1\"\u003e\u003ccaption language=\"En\"\u003e\u003cdiv class=\"CaptionNumber\"\u003eTable 5\u003c/div\u003e\u003cdiv class=\"CaptionContent\"\u003e\u003cp\u003e SSI risk analysis by daily precipitation range using logistic regression\u003c/p\u003e\u003c/div\u003e\u003c/caption\u003e\u003ccolgroup cols=\"5\"\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c5\" colnum=\"5\"\u003e\u003c/div\u003e\u003cthead\u003e\u003ctr\u003e\u003cth align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/th\u003e\u003cth align=\"left\" colname=\"c2\"\u003e\u003cp\u003eUninfected group\u003c/p\u003e\u003cp\u003en\u0026thinsp;=\u0026thinsp;10373(95.34%)\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c3\"\u003e\u003cp\u003eSSI group\u003c/p\u003e\u003cp\u003en\u0026thinsp;=\u0026thinsp;507(4.66%)\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c4\"\u003e\u003cp\u003eOdds ratio\u003c/p\u003e\u003cp\u003e(95% CI)\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c5\"\u003e\u003cp\u003ep-value\u003c/p\u003e\u003c/th\u003e\u003c/tr\u003e\u003ctr\u003e\u003cth align=\"left\" colspan=\"5\" nameend=\"c5\" namest=\"c1\"\u003e\u003cp\u003e\u003cem\u003eDaily precipitation(mm)\u003c/em\u003e\u003c/p\u003e\u003c/th\u003e\u003c/tr\u003e\u003ctr\u003e\u003cth align=\"left\" colname=\"c1\"\u003e\u003cp\u003eThe day of surgery\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/th\u003e\u003cth align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/th\u003e\u003cth align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/th\u003e\u003cth align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/th\u003e\u003c/tr\u003e\u003c/thead\u003e\u003ctbody\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e0\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e7333\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e363(4.72%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003eRef\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e\u0026ge;\u0026thinsp;0, \u0026lt; 10\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e2195\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e103(4.48%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e0.95(0.76\u0026ndash;1.19)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e0.66\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e\u0026ge;\u0026thinsp;10\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e845\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e41(4.63%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e0.98(0.70\u0026ndash;1.36)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e0.89\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e\u003cb\u003e*Until 1 week after surgery\u003c/b\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e0\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e1815\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e80(4.22%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003eRef\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e\u0026ge;\u0026thinsp;0, \u0026lt; 10\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e7700\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e386(4.77%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e1.14(0.89\u0026ndash;1.46)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e0.30\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e\u0026ge;\u0026thinsp;10\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e858\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e41(4.56%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e1.09(0.74\u0026ndash;1.59)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e0.68\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colspan=\"5\" nameend=\"c5\" namest=\"c1\"\u003e\u003cp\u003eRef\u0026thinsp;=\u0026thinsp;reference\u003c/p\u003e\u003cp\u003e* average of the daily precipitation for the 7 days after the day of surgery\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003c/tbody\u003e\u003c/colgroup\u003e\u003c/table\u003e\u003c/div\u003e\u003c/p\u003e"},{"header":"Discussion","content":"\u003cp\u003eThere have been several studies analyzing the risk factors for SSI following spinal surgeries. However, this study is the first large-scale analysis of risk factors for SSI specifically after SFS, a type of spinal surgery where infections can be severe. This study particularly focused on how temporal, seasonal, and climatic factors influence the occurrence of SSI after SFS in a large patient cohort. Previous studies have reported that warmer temperatures and warmer seasons can increase the risk of SSI[\u003cspan additionalcitationids=\"CR22 CR23 CR24\" citationid=\"CR21\" class=\"CitationRef\"\u003e21\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR25\" class=\"CitationRef\"\u003e25\u003c/span\u003e]. However, analyzing climatic factors has been challenging due to variations in the timing of surgery, the hospital addresses where patients were admitted, and the addresses of their residences post-discharge. These factors make it difficult to conduct large-scale studies tailored to individual patients. In our study, we combined clinical data with weather data provided by the Korea Meteorological Administration, allowing for an analysis of climate factors on a large cohort of patients.\u003c/p\u003e\u003cp\u003eAdditionally, we divided temperature and humidity into different ranges to assess whether increases in these factors contributed to the higher risk of SSI. As shown in Table\u0026nbsp;\u003cspan refid=\"Tab1\" class=\"InternalRef\"\u003e1\u003c/span\u003e, the risk factors related to surgery were consistent with previously reported findings[\u003cspan additionalcitationids=\"CR27 CR28 CR29 CR30 CR31\" citationid=\"CR26\" class=\"CitationRef\"\u003e26\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR32\" class=\"CitationRef\"\u003e32\u003c/span\u003e]. The risk of SSI increased with age, and particularly for patients with a BMI greater than 35, the risk was elevated. The risk of SSI also increased as the duration of the surgery lengthened, but the number of surgeons involved did not significantly affect the risk.\u003c/p\u003e\u003cp\u003eWhile prior studies have suggested that warmer seasons increase the risk of SSI[\u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e16\u003c/span\u003e, \u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e17\u003c/span\u003e, \u003cspan citationid=\"CR21\" class=\"CitationRef\"\u003e21\u003c/span\u003e, \u003cspan citationid=\"CR22\" class=\"CitationRef\"\u003e22\u003c/span\u003e, \u003cspan citationid=\"CR25\" class=\"CitationRef\"\u003e25\u003c/span\u003e], this study did not find that seasonal changes in South Korea had a significant effect on SSI risk. However, monthly analysis showed that, although not statistically significant, January and February had relatively lower rates of SSI following SFS. This could be attributed to South Korea's unique climate and its medical training system. As reported in previous studies, SSI risk is generally lower during colder weather, and in South Korea, the medical training system ends in February. This may result in higher levels of experience and proficiency among attending surgeons, interns, and residents involved in both the surgeries and postoperative care during this time, contributing to a lower risk of SSI.\u003c/p\u003e\u003cp\u003eIn the analysis of SSI risk by the day of the week, surgeries performed on Wednesdays showed a lower risk of SSI. Since Wednesday is the middle weekday, this may allow more time for both preoperative and postoperative care during working days, reducing the risk of infection. Although not directly related to SSI, a study reported that mortality rates are higher when nonemergent major surgery is performed on a Friday compared to Monday through Wednesday[\u003cspan citationid=\"CR33\" class=\"CitationRef\"\u003e33\u003c/span\u003e]. This finding suggests that the day of the week on which SFS is performed may also significantly influence the SSI rate.\u003c/p\u003e\u003cp\u003eIn this study, we also analyzed whether objective climatic indicators such as temperature and humidity had a correlation with the occurrence of SSI following SFS. We hypothesized that not only the weather on the day of surgery, but also the climate during the postoperative care period (one week and one month post-surgery), might have a relationship with the occurrence of SSI. Figure\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003e shows a correlation coefficient of 0.51 for the average daily temperature during the first week following surgery, and Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003e shows a correlation coefficient of 0.56 for the daily maximum temperature. These moderate correlations indicate that rising temperatures are associated with an increase in the SSI rate. Additionally, as shown in Fig.\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003e, there was a significant correlation of 0.65 between the daily average humidity and the occurrence of SSI during the first week post-surgery, proving a notable correlation between temperature, humidity, and the incidence of SSI after SFS.\u003c/p\u003e\u003cp\u003eWe also conducted an analysis to examine whether changes in temperature, humidity, and precipitation could be risk factors for SSI following SFS. As shown in Table\u0026nbsp;\u003cspan refid=\"Tab3\" class=\"InternalRef\"\u003e3\u003c/span\u003e, an increase in temperature generally led to an increase in the odds ratio. Specifically, when the daily maximum temperature on the day of surgery exceeded 30\u0026deg;C, the odds ratio for SSI was approximately twice as high as when the temperature was between \u0026minus;\u0026thinsp;5\u0026deg;C and 0\u0026deg;C, indicating a significantly increased risk of SSI following SFS in warmer conditions. Previous big data analyses of SSI risk for surgeries in other surgical fields also reported an increase in the odds ratio with rising temperatures[\u003cspan citationid=\"CR34\" class=\"CitationRef\"\u003e34\u003c/span\u003e]. Although the trend in this study was irregular, it confirmed that increasing temperature generally raises the risk of SSI after SFS.\u003c/p\u003e\u003cp\u003eIn the analysis of humidity as a risk factor, no significant difference in the odds ratio was found across humidity ranges. However, in climates with humidity levels above 90%, a slight increase in the odds ratio was observed. While some previous studies have reported that high humidity increases the risk of SSI[\u003cspan citationid=\"CR35\" class=\"CitationRef\"\u003e35\u003c/span\u003e], and others have suggested that intraoperative humidity has no significant impact[\u003cspan citationid=\"CR36\" class=\"CitationRef\"\u003e36\u003c/span\u003e], no study to date has specifically investigated the effect of humidity on SSI following SFS. In this study, we demonstrated that a high humidity may contribute to an increased risk of SSI after SFS\u003c/p\u003e\u003cp\u003eRising temperature and humidity could potentially worsen hygiene conditions for patients post-surgery, increasing the risk of infection. Moreover, high temperature and humidity can cause psychological stress in both humans and animals, leading to dysregulation of the hypothalamic-pituitary-adrenal axis and increased cortisol levels, which could result in decreased immune function, contributing to an increased risk of infection post-surgery[\u003cspan additionalcitationids=\"CR38 CR39\" citationid=\"CR37\" class=\"CitationRef\"\u003e37\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR40\" class=\"CitationRef\"\u003e40\u003c/span\u003e].\u003c/p\u003e\u003cp\u003eThis study reaffirmed that known factors such as age, BMI, duration of surgery, and amount of transfusion contribute to the risk of SSI following spine fusion surgery. While seasonal variability in SSI risk did not reach statistical significance, the finding that the risk of infection was relatively lower in the coldest months of January and February suggests that colder weather may contribute to reducing the risk of infection post-surgery.\u003c/p\u003e\u003cp\u003eThis is the first study to analyze the risk of SSI after SFS using large-scale clinical and climatic big data. However, there are several limitations. First, as this study was retrospective, we were limited to relying solely on medical records. Second, the operative definition of postoperative infection was incomplete. Due to the retrospective nature, we had to rely on records, and there were cases where data on postoperative SSI, such as diagnostic codes, were missing. We had to infer infection based on antibiotic use, which might explain the higher postoperative SSI rate compared to previous studies. In this study, we applied different weather data based on the patient's hospital address during admission and their residential address after discharge. However, this assumption that patients stayed at their homes after discharge may introduce errors.\u003c/p\u003e\u003cp\u003eIn conclusion, as previously reported, age, obesity, prolonged surgery time, and the amount of transfusion contribute to the risk of SSI following SFS. Temporal and seasonal analysis showed that the risk of SSI was relatively lower during the colder months of January and February, and weekday analysis indicated that surgeries performed on Wednesdays had a significantly lower risk of infection. This study focused particularly on the correlation between climate factors and SSI risk following SFS, showing that average daily maximum temperature and daily average humidity during the first week post-surgery were significantly correlated with the incidence of SSI. Moreover, temperature and humidity increases were identified as risk factors for SSI. Further analysis of additional climatic factors related to the occurrence of SSI is warranted in future studies.\u003c/p\u003e"},{"header":"Declarations","content":"\u003ch2\u003eAuthor Contribution\u003c/h2\u003e\u003cp\u003eMyung-Sup Ko, Sang-Il Kim, Young-Hoon Kim and Kee-Yong Ha contributed to the study conception and design. Material preparation, data collection and analysis were performed by Myung-Sup Ko, Soyeong Park, Yohan Ko, Hyung-Youl Park, and Yunseong Kim. The first draft of the manuscript was written by Myung-Sup Ko, Soyeong Park and Young-Hoon Kim. The overall supervision of this project was done by Yohan Ko and Sang-Il Kim. All authors commented on previous versions of the manuscript. All authors read and approved the final manuscript.\u003c/p\u003e\u003ch2\u003eData Availability\u003c/h2\u003e\u003cp\u003eThe datasets generated during the current study are available from the corresponding author on reasonable request.\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\n\u003cli\u003eHoran TC, Culver DH, Gaynes RP, Jarvis WR, Edwards JR, Reid CR (1993) Nosocomial infections in surgical patients in the United States, January 1986-June 1992. National Nosocomial Infections Surveillance (NNIS) System. Infect Control Hosp Epidemiol 14:73-80. doi: 10.1086/646686\u003c/li\u003e\n\u003cli\u003eFei Q, Li J, Lin J, Li D, Wang B, Meng H, Wang Q, Su N, Yang Y (2016) Risk Factors for Surgical Site Infection After Spinal Surgery: A Meta-Analysis. World Neurosurg 95:507-515. doi: 10.1016/j.wneu.2015.05.059\u003c/li\u003e\n\u003cli\u003ePull ter Gunne AF, Cohen DB (2009) Incidence, prevalence, and analysis of risk factors for surgical site infection following adult spinal surgery. Spine (Phila Pa 1976) 34:1422-1428. doi: 10.1097/BRS.0b013e3181a03013\u003c/li\u003e\n\u003cli\u003eKim JH, Ahn DK, Kim JW, Kim GW (2015) Particular Features of Surgical Site Infection in Posterior Lumbar Interbody Fusion. Clin Orthop Surg 7:337-343. doi: 10.4055/cios.2015.7.3.337\u003c/li\u003e\n\u003cli\u003eRamo BA, Roberts DW, Tuason D, McClung A, Paraison LE, Moore HGt, Sucato DJ (2014) Surgical site infections after posterior spinal fusion for neuromuscular scoliosis: a thirty-year experience at a single institution. J Bone Joint Surg Am 96:2038-2048. doi: 10.2106/jbjs.N.00277\u003c/li\u003e\n\u003cli\u003eSchimmel JJ, Horsting PP, de Kleuver M, Wonders G, van Limbeek J (2010) Risk factors for deep surgical site infections after spinal fusion. 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J Bone Joint Surg Am 90:62-69. doi: 10.2106/jbjs.F.01515\u003c/li\u003e\n\u003cli\u003eHo C, Sucato DJ, Richards BS (2007) Risk factors for the development of delayed infections following posterior spinal fusion and instrumentation in adolescent idiopathic scoliosis patients. Spine (Phila Pa 1976) 32:2272-2277. doi: 10.1097/BRS.0b013e31814b1c0b\u003c/li\u003e\n\u003cli\u003eKurtz SM, Lau E, Ong KL, Carreon L, Watson H, Albert T, Glassman S (2012) Infection risk for primary and revision instrumented lumbar spine fusion in the Medicare population. J Neurosurg Spine 17:342-347. doi: 10.3171/2012.7.Spine12203\u003c/li\u003e\n\u003cli\u003eChehrassan M, Nikouei F, Shakeri M, Behnamnia A, Mahabadi EA, Ghandhari H (2024) The role of environmental and seasonal factors in spine deep surgical site infection: the air pollution, a factor that may be underestimated. Eur Spine J 33:3148-3153. doi: 10.1007/s00586-024-08183-z\u003c/li\u003e\n\u003cli\u003eSahtoe APH, Duraku LS, van der Oest MJW, Hundepool CA, de Kraker M, Bode LGM, Zuidam JM (2021) Warm Weather and Surgical Site Infections: A Meta-analysis. Plastic and Reconstructive Surgery \u0026ndash; Global Open 9:e3705. doi: 10.1097/gox.0000000000003705\u003c/li\u003e\n\u003cli\u003eDurkin MJ, Dicks KV, Baker AW, Moehring RW, Chen LF, Sexton DJ, Lewis SS, Anderson DJ (2015) Postoperative infection in spine surgery: does the month matter? Journal of Neurosurgery: Spine 23:128-134\u003c/li\u003e\n\u003cli\u003eShuman WH, Baron RB, Gal JS, Li AY, Neifert SN, Hannah TC, Dreher N, Schupper AJ, Steinberger JM, Caridi JM (2022) Seasonal effects on surgical site infections following spine surgery. World Neurosurgery 161:e174-e182\u003c/li\u003e\n\u003cli\u003eSahtoe AP, Duraku LS, van der Oest MJ, Hundepool CA, de Kraker M, Bode LG, Zuidam JM (2021) Warm weather and surgical site infections: a meta-analysis. Plastic and Reconstructive Surgery\u0026ndash;Global Open 9:e3705\u003c/li\u003e\n\u003cli\u003eSalvetti DJ, Tempel ZJ, Goldschmidt E, Colwell NA, Angriman F, Panczykowski DM, Agarwal N, Kanter AS, Okonkwo DO (2018) Low preoperative serum prealbumin levels and the postoperative surgical site infection risk in elective spine surgery: a consecutive series. J Neurosurg Spine 29:549-552. doi: 10.3171/2018.3.Spine171183\u003c/li\u003e\n\u003cli\u003eLiu JM, Deng HL, Chen XY, Zhou Y, Yang D, Duan MS, Huang SH, Liu ZL (2018) Risk Factors for Surgical Site Infection After Posterior Lumbar Spinal Surgery. 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Infect Control Hosp Epidemiol 38:809-816. doi: 10.1017/ice.2017.84\u003c/li\u003e\n\u003cli\u003eShuman WH, Baron RB, Gal JS, Li AY, Neifert SN, Hannah TC, Dreher N, Schupper AJ, Steinberger JM, Caridi JM, Choudhri TF (2022) Seasonal Effects on Surgical Site Infections Following Spine Surgery. World Neurosurg 161:e174-e182. doi: 10.1016/j.wneu.2022.01.100\u003c/li\u003e\n\u003cli\u003eSahtoe APH, Duraku LS, van der Oest MJW, Hundepool CA, de Kraker M, Bode LGM, Zuidam JM (2021) Warm Weather and Surgical Site Infections: A Meta-analysis. Plast Reconstr Surg Glob Open 9:e3705. doi: 10.1097/gox.0000000000003705\u003c/li\u003e\n\u003cli\u003eOgawa T, Yoshii T, Morishita S, Moriwaki M, Okawa A, Nazarian A, Fushimi K, Fujiwara T (2021) Seasonal impact on surgical site infections in hip fracture surgery: Analysis of 330,803 cases using a nationwide inpatient database. 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Building and Environment 233:110073\u003c/li\u003e\n\u003cli\u003eYang M, Luo Y, Hao XZ, Guo MY, Li W, Hu YH (2021) Effects of high temperature and high humidity stress on the negative feedback regulation of hippocampus on HPA axis in rats. Neuro Endocrinol Lett 42:312-320\u003c/li\u003e\n\u003c/ol\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":false,"highlight":"","institution":"","isAcceptedByJournal":true,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"european-spine-journal","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"esjo","sideBox":"Learn more about [European Spine Journal](http://link.springer.com/journal/586)","snPcode":"586","submissionUrl":"https://submission.springernature.com/new-submission/586/3","title":"European Spine Journal","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"stoa","reportingPortfolio":"Springer Hybrid","inReviewEnabled":true,"inReviewRevisionsEnabled":false},"keywords":"surgical site infection, spine fusion surgery, risk factor, climate, big data","lastPublishedDoi":"10.21203/rs.3.rs-7002924/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-7002924/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003ch2\u003ePurpose\u003c/h2\u003e\u003cp\u003eThis study aimed to identify both clinical and meteorological risk factors for surgical site infection (SSI) following spine fusion surgery (SFS), with a focus on integrating medical big data and weather data.\u003c/p\u003e\u003ch2\u003eMethods\u003c/h2\u003e\u003cp\u003eWe retrospectively analyzed data from 10,880 patients who underwent SFS between January 2013 and November 2022 at eight university-affiliated hospitals. Clinical data were sourced from the Catholic Medical Center Clinical Data Warehouse, and regional meteorological data were obtained from the Korea Meteorological Administration. SSI was defined based on diagnostic codes and antibiotic prescriptions within three months postoperatively. Risk factors were assessed using logistic regression and correlation analyses.\u003c/p\u003e\u003ch2\u003eResults\u003c/h2\u003e\u003cp\u003eThe overall SSI incidence was 4.66% (507 cases). Significant clinical risk factors included older age, severe obesity (BMI\u0026thinsp;\u0026ge;\u0026thinsp;35), longer operative time, and higher intraoperative transfusion volume. Surgeries conducted on Wednesdays were associated with a lower SSI risk. While seasonal variation was not statistically significant, SSIs were relatively less common in January and February. Climatic factors, including higher average temperature and humidity during the first postoperative week, were moderately correlated with increased SSI risk (temperature r\u0026thinsp;=\u0026thinsp;0.51; humidity r\u0026thinsp;=\u0026thinsp;0.65, both p\u0026thinsp;\u0026lt;\u0026thinsp;0.01). Maximum daily temperatures above 30\u0026deg;C significantly increased SSI risk (OR\u0026thinsp;=\u0026thinsp;2.03, p\u0026thinsp;=\u0026thinsp;0.03).\u003c/p\u003e\u003ch2\u003eConclusion\u003c/h2\u003e\u003cp\u003eThis large-scale study is the first to integrate clinical and climatic big data in assessing SSI risk after SFS. In addition to established clinical factors, environmental conditions such as temperature and humidity were shown to influence infection risk. These findings suggest that weather-related factors should be considered in perioperative infection control strategies. Further prospective studies are needed to validate these results and guide clinical practice.\u003c/p\u003e","manuscriptTitle":"Climatic and Clinical Risk Factors for Surgical Site Infection Following Spine Fusion Surgery: A Large-Scale Big Data Analysis","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2025-07-15 11:11:20","doi":"10.21203/rs.3.rs-7002924/v1","editorialEvents":[{"type":"communityComments","content":0},{"type":"decision","content":"Revision requested","date":"2025-09-17T18:45:42+00:00","index":"","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2025-08-07T11:01:15+00:00","index":"hide","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2025-07-31T11:52:49+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"140779880940354088652052524017109477680","date":"2025-07-15T02:55:04+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"34198009703149652418938674516953993626","date":"2025-07-12T19:12:15+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"32596291602349190541789798379440734939","date":"2025-07-11T09:52:25+00:00","index":"hide","fulltext":""},{"type":"reviewersInvited","content":"","date":"2025-07-10T19:24:56+00:00","index":"","fulltext":""},{"type":"editorAssigned","content":"","date":"2025-07-04T01:55:59+00:00","index":"","fulltext":""},{"type":"checksComplete","content":"","date":"2025-07-04T01:54:32+00:00","index":"","fulltext":""},{"type":"submitted","content":"European Spine Journal","date":"2025-06-29T13:11:50+00:00","index":"","fulltext":""}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"european-spine-journal","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"esjo","sideBox":"Learn more about [European Spine Journal](http://link.springer.com/journal/586)","snPcode":"586","submissionUrl":"https://submission.springernature.com/new-submission/586/3","title":"European Spine Journal","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"stoa","reportingPortfolio":"Springer Hybrid","inReviewEnabled":true,"inReviewRevisionsEnabled":false}}],"origin":"","ownerIdentity":"33e0091e-4921-4b20-a8a8-251334a4e90a","owner":[],"postedDate":"July 15th, 2025","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"published-in-journal","subjectAreas":[],"tags":[],"updatedAt":"2026-01-12T16:01:02+00:00","versionOfRecord":{"articleIdentity":"rs-7002924","link":"https://doi.org/10.1007/s00586-025-09643-w","journal":{"identity":"european-spine-journal","isVorOnly":false,"title":"European Spine Journal"},"publishedOn":"2026-01-10 15:57:23","publishedOnDateReadable":"January 10th, 2026"},"versionCreatedAt":"2025-07-15 11:11:20","video":"","vorDoi":"10.1007/s00586-025-09643-w","vorDoiUrl":"https://doi.org/10.1007/s00586-025-09643-w","workflowStages":[]},"version":"v1","identity":"rs-7002924","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-7002924","identity":"rs-7002924","version":["v1"]},"buildId":"8U1c8b4HqxoKbykW_rLl7","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}