Risk Factors for Postoperative Delirium in Elderly Hip Fracture Patients: A Prospective Observational Analysis

Risk Factors for Postoperative Delirium in Elderly Hip Fracture Patients: A Prospective Observational 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 Risk Factors for Postoperative Delirium in Elderly Hip Fracture Patients: A Prospective Observational Analysis Yuzhi Wei, Haotian Wu, Chunyu Feng, Yujie Wang, Ziheng Qi, Huan Zhang This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-6635767/v1 This work is licensed under a CC BY 4.0 License Status: Posted Version 1 posted You are reading this latest preprint version Abstract Background Postoperative Delirium (POD) is a relatively common acute neurocognitive complication in elderly patients with hip fractures. However, its exact incidence rate and risk factors have not been fully elucidated. Methods This prospective study enrolled 238 elderly patients undergoing surgical repair for hip fractures between January 2022 and September 2024. Using univariate and multivariate logistic regression analyses, we identified factors associated with POD and evaluated its correlation with intensive care unit (ICU) length of stay, total hospitalization duration, and postoperative complications. Results The incidence of POD was 31.9% (76/238). Multivariate analysis revealed that advanced age (> 82 years; adjusted OR = 2.25, 95% CI: 1.13–4.45, P = 0.020), prolonged preoperative waiting time (> 90 hours; OR = 2.65, 95% CI: 1.30–5.37, P = 0.007), and frailty (OR = 2.40, 95% CI: 1.08–5.32, P = 0.031) were independently associated with POD. Patients with POD exhibited significantly prolonged ICU stays (median 17.8 days vs. 0 days, P < 0.001) and total hospitalization (13 days vs. 10 days, P < 0.001), along with higher rates of postoperative infections (urinary tract infections: 47.4% vs. 20.4%, P < 0.001). Conclusion POD is highly prevalent in elderly hip fracture patients and strongly linked to frailty, prolonged preoperative waiting time, and advanced age. These factors substantially increase healthcare burden, highlighting the need for optimized preoperative assessment, reduced waiting times, and multidisciplinary interventions to mitigate POD risk. Postoperative delirium Hip fracture Frailty Preoperative waiting time Aging Figures Figure 1 Introduction Postoperative delirium (POD) represents a frequent neuropsychiatric complication in elderly hip fracture patients, typically occurring within 24–72 hours after surgery and lasting for hours to days[ 1 , 2 ]. The accelerated process of global aging has given rise to the prevalence of hip fractures. This vulnerable cohort, characterized by osteoporosis prevalence (69% in fragility fracture cohorts[ 3 ]), impaired ambulatory capacity, and complex multimorbidity profiles[ 3 , 4 ], exhibits disproportionately high POD incidence rates (13%-70%)[ 4 , 5 ]. POD is characterized by acute neurocognitive deterioration, with core manifestations including fluctuating consciousness, impaired attention (83% incidence[ 6 ]), and behavioral dysregulation. Clinical subtypes—hyperactive (agitation/hallucinations), hypoactive (lethargy/apathy), and mixed—exhibit distinct behavioral patterns. However, only 20.9% of delirium cases were systematically recorded, and the emergency department missed up to 75% of cases[ 7 ], indicating significant diagnostic challenges. This neuropsychiatric complication exerts bidirectional strain on healthcare systems and patient outcomes. ICU stays and total hospitalization durations are significantly prolonged in patients with POD. Studies show that the ICU stay is prolonged by 36% (after risk adjustment) and total hospitalization is prolonged by 22% in patients with POD[ 8 ]. Longitudinal data confirm that POD prolongs rehabilitation duration by 6.5 days, amplifies the risk of secondary complications such as pressure ulcers[ 9 , 10 ] and surgical site infections (OR = 4.38) [ 11 ], and is significantly associated with increased long-term mortality (OR = 2.11, P = 0.009, I 2 = 62.5%)[ 12 ]. POD significantly impacts elderly patients with hip fractures, yet gaps remain in understanding its incidence and modifiable risk factors. Existing research has limitations in sample size and risk factor analysis, particularly regarding the complex interactions between risk factors and POD development. As hip fractures increase in aging populations, understanding POD in this vulnerable group becomes critical. This study aims to identify risk factors for POD and evaluate its association with clinical outcomes, including ICU stay, hospitalization duration, and postoperative complications. Findings may guide targeted preventive strategies to improve patient care and reduce healthcare burden. Materials and methods Study Design This prospective observational study adhered to the STROBE guidelines for observational research and was conducted at Beijing Tsinghua Chang Gung Hospital. It consecutively enrolled patients aged 60 years or older with imaging-confirmed hip fractures requiring surgery between January 2022 and November 2023. The protocol was approved by the institutional ethics committee (No. 21277-0-01), complied with the Declaration of Helsinki, and prospectively registered at ClinicalTrials.gov (NCT05246254). All participants provided witnessed written informed consent after trained researchers explained the study process. Data collection used standardized case report forms integrated with the electronic medical record system for real-time perioperative data verification. Inclusion and Exclusion Criteria This prospective cohort study enrolled 292 patients hospitalized for hip fractures between January 1, 2022, and November 30, 2023. Inclusion criteria were: participants aged 60 years or older; presence of hip fracture; signed informed consent form; American Society of Anesthesiologists (ASA) class I-IV; and surgery performed by a consistent anesthetic and surgical team. Exclusion criteria included: inability to provide informed consent; conservative treatment without surgery; duplicate fracture records; pre-existing cognitive impairment; inability to complete cognitive function tests; delirium during initial assessment; diagnosed psychiatric or substance use disorders; and incomplete or missing follow-up data. All patients received standardized preoperative preparation, anesthetic, and postoperative management. The primary objective of this study was to evaluate the incidence of POD. Standardized Anesthetic Management Protocol Environmental Control: Operating room temperature was strictly maintained between 20–23°C, with relative humidity kept at 50–60%; (ii) Temperature Management: A convection forced-air warming system and intravenous fluid warming device were systematically combined to maintain normal body temperature (36.5–37.2°C); (iii) Venous Access and Monitoring: An 18G venous catheter was established in the upper limb for lactated Ringer's solution infusion (1–5 mL/min). Continuous monitoring included three-lead electrocardiography, non-invasive oscillometric blood pressure, and pulse oximetry, with recordings of systolic blood pressure, heart rate, and oxygen saturation every 5 minutes; (iv) Neuraxial Anesthesia and Sedation: Senior anesthesiologists performed combined spinal-epidural anesthesia(CSEA)at the L2–3/ L3–4 interspace per standard protocol. With the patient in the right lateral position, a 16-gauge Tuohy needle was inserted via a paramedian approach. After confirming the epidural space using the loss-of-resistance technique, a 25-gauge Whitacre spinal needle was placed until cerebrospinal fluid returned, followed by intrathecal injection of 0.75% isobaric ropivacaine (1.8–2.2 mL). Subsequently, an epidural catheter was advanced 3–4 cm toward the cephalad direction. In the supine position, a standardized hip wedge was used to achieve 15° left uterine displacement. Dexmedetomidine was continuously infused (0.1–0.3 µg/kg/h) to maintain Ramsay Sedation Scale scores of 2–3; (v) General anesthesia (GA) was administered for patients with neuraxial anesthesia contraindications. Induction protocol included intravenous lidocaine (1.5 mg/kg), etomidate (0.2–0.3 mg/kg) or propofol (2–4 mg/kg), sufentanil (0.2–0.4 µg/kg), and rocuronium (0.6 mg/kg). Post-intubation mechanical ventilation maintained P ET CO2 35–45 mmHg. Maintenance combined intravenous target-controlled infusion (propofol 2–6 mg/kg/h or dexmedetomidine 0.1–0.7 µg/kg/h) with remifentanil (0.04–0.2µg/kg/min), supplemented by sevoflurane (1.0-2.5 vol%) to sustain bispectral index 40–60. Hemodynamic targets included mean arterial pressure within 20% baseline and heart rate 55–100 bpm. Perioperatively, patients received protocolized postanesthesia care unit (PACU) management incorporating ultrasound-guided catheter-based continuous femoral nerve block (CFNB) as part of a multimodal analgesic strategy. (vi) Advanced Monitoring: Invasive arterial catheterization was routinely performed in patients with ASA class ≥ III or cardiopulmonary comorbidities; (vii) Hemodynamic Optimization: Goal-directed hemodynamic therapy was implemented to optimize volume status and maintain blood pressure within the ideal range. Observation Indicators Preoperative variables included age, gender, BMI, smoking history, alcohol abuse, comorbidities (hypertension, heart disease, diabetes mellitus, kidney diseases, history of stroke), and Charlson Comorbidity Index (CCI), with patients categorized into low (≤ 2) and high (> 2) comorbidity burden groups. Nutritional status was assessed via the Mini Nutritional Assessment (MNA) scale, classifying participants as malnourished (< 17), at risk of malnutrition (17–23.5), or with normal nutritional status (≥ 24). Frailty status, based on the Frailty Index (FI)[ 13 ], divided participants into non-frail (FI < 0.25) and frail (FI ≥ 0.25) status. Other preoperative factors included medication history, fracture type and side, presence of multiple fractures, history of contralateral hip fracture, preoperative laboratory test results, Prognostic Nutrition Index (PNI), preoperative waiting time (from admission to surgery), and ASA classification. (ii)Operative data comprised surgical method, anesthesia type, operation duration, and estimated blood loss. (iii)Postoperative factors covered complications (venous thromboembolism, urinary tract infections, pulmonary infections, myocardial infarction, stroke, gastrointestinal hemorrhage), hemoglobin level on postoperative day 1, ICU stay duration, and total hospital length of stay. Outcome measures The Confusion Assessment Method (CAM)[ 14 , 15 ], the internationally validated gold-standard instrument for delirium detection, was systematically implemented with its four diagnostic pillars: (1) acute onset/fluctuating course, (2) inattention, (3) disorganized thinking, and (4) altered consciousness. Demonstrating exceptional psychometric properties (sensitivity: 95–100%; specificity: 90–95%), this protocol enabled standardized identification of both hyperactive and hypoactive delirium subtypes. Certified delirium assessments were conducted by a dual-qualified clinician (senior anesthesiologist holding neurology subspecialty certification) at critical postoperative intervals (POD 1, 2, 3, 5, 7) using time-series CAM evaluations to capture dynamic symptom trajectories. The rigorous assessment framework incorporated serial neurological examinations to differentiate transient cognitive changes from true delirium episodes. Outcome indicators The primary outcome was the incidence of POD assessed using the CAM. Secondary outcomes included hospital length of stay, defined as days from admission to discharge, and ICU length of stay calculated from ICU admission to transfer and postoperative complications. Outcome assessors received standardized training in delirium evaluation protocols prior to data collection. Statistical analysis The analytical cohort was stratified based on POD occurrence within 7 days. Continuous variables underwent normality assessment using the Kolmogorov-Smirnov test. Metabolic parameters (BMI, total protein, albumin, serum sodium/potassium/calcium) and nutritional indices (absolute lymphocyte count, prognostic nutritional index) demonstrating normal distribution were expressed as mean ± SD. Surgical parameters (age, preoperative waiting time, operative duration, intraoperative blood loss) and care metrics (hospital/ICU stay) with non-normal distribution were reported as median (IQR). Categorical variables were presented as frequencies (percentages). Intergroup comparisons employed Student's t-test (parametric) or Wilcoxon rank-sum test (non-parametric) for continuous variables, and χ² test or Fisher's exact test for categorical variables. Univariate logistic regression identified potential POD predictors. The multivariate model adjusted for: (1) demographic confounders (age > 82 years, hypertension history); (2) comorbidities (respiratory diseases, stroke history, CCI); (3) perioperative factors (preoperative waiting time > 90h, frailty status, ASA classification); (4) postoperative complications (urinary/pulmonary infections); 5) nutritional determinants (total protein, PNI). Adjusted odds ratios with 95% confidence intervals were calculated. All analyses were conducted using SPSS 27.0 (IBM Corp.) and Free Statistics 1.7.1 with α = 0.05 for significance. Statistical analysis was conducted using SPSS 27.0 (IBM, Armonk, NY, USA) and Free Statistics software (version 1.7.1) ( https://www.clinicalscientists.cn/freestatistics/ ). Outcomes Between January 2021 and November 2023, 292 patients underwent eligibility screening, with 238 meeting inclusion criteria (Figure 1). The prospective cohort demonstrated complete follow-up (100% retention) and full data completeness for all prespecified endpoints. No attrition or missing data occurred during the study period. Characteristics of the Study Population The study cohort comprised 238 geriatric hip fracture patients with mean age 79.0±8.7 years (females: 73.1%, n=174). POD occurred in 76 cases (31.9%). Comparative analysis revealed significant intergroup disparities in demographic and clinical profiles: POD patients demonstrated significantly higher prevalence of advanced age (>82 years: 63.2% vs 34.0%, P<0.001), preoperative frailty (76.3% vs 34.6%, OR=6.10, 95%CI 3.28-11.34), and malnutrition (22.4% vs 4.3%, P<0.001). Nutritional biomarkers showed marked deterioration in POD group - total albumin (66.8 ± 5.5 vs 69.3 ± 5.4 g/L, P<0.001) and PNI (37.2±4.0 vs 39.5±4.0, P<0.001). Comparative analysis of anesthetic modalities revealed a predominance of combined CSEA over GA in both POD and non-POD cohorts (67.1% vs. 32.9% and 72.2% vs. 27.8%, respectively), though these proportional differences lacked statistical significance (P>0.05). Similarly, no significant intergroup disparities emerged in operative strategy selection, with comparable utilization rates of arthroplasty versus internal fixation (46.6% vs. 53.4%, P=0.337) across study populations, as detailed in Table 1. These findings suggest that neither anesthetic modality nor surgical approach independently contributed to delirium risk stratification in this cohort. Table 1. Comparison of baseline characteristics and other covariables between patients with and without postoperative delirium (POD). Parameter Total n = 238 With POD n = 76 With not POD n = 162 P value Age ** , years 79.0 ± 8.7 82.5 ± 7.8 77.3 ± 8.6 < 0.001 Gender, n (%) 0.281 Female 174 (73.1) 59 (77.6) 115 (71.0) Male 64 (26.9) 17 (22.4) 47 (29.0) BMI, kg/m 2 24.0 ± 4.4 23.3 ± 4.7 24.3 ± 4.3 0.110 Active smoking, n (%) 12 (5.0) 3 (3.9) 9 (5.6) 0.757 Alcohol abuse, n (%) 6 (2.5) 1 (1.3) 5 (3.1) 0.667 Comorbidity, n (%) Hypertension * 163 (68.5) 59 (77.6) 104 (64.2) 0.038 Heart disease 90 (37.8) 33 (43.4) 57 (35.2) 0.222 Diabetes mellitus 76 (31.9) 22 (28.9) 54 (33.3) 0.499 Kidney disease 15 (6.3) 5 (6.6) 10 (6.2) 1.000 Respiratory diseases * 178 (74.8) 65 (85.5) 113 (69.8) 0.009 History of stroke * 68 (28.6) 29 (38.2) 39 (24.1) 0.025 CCI ** 5.0 (4.0, 6.0) 6.0 (5.0, 7.0) 4.0 (3.0, 5.0) < 0.001 MNA scale ** , n (%) < 0.001 Normal nutrition 56 (23.5) 9 (11.8) 47 (29) At risk 158 (66.4) 50 (65.8) 108 (66.7) Malnourished 24 (10.1) 17 (22.4) 7 (4.3) Frailty ** , n (%) 114 (47.9) 58 (76.3) 56 (34.6) < 0.001 Medication History, n (%) Hormone 11 (4.6) 3 (3.9) 8 (4.9) 1.000 Zoledronic acid 5 (2.1) 0 (0) 5 (3.1) 0.180 Type of fracture, n (%) 0.286 Femoral neck 128 (54.2) 35 (47.3) 93 (57.4) Continued Table 1 Intertrochanteric 104 (44.1) 38 (51.4) 66 (40.7) Subtrochanteric 4 (1.7) 1 (1.4) 3 (1.9) Side, n (%) 0.779 Left 118 (50.0) 38 (51.4) 80 (49.4) Right 118 (50.0) 36 (48.6) 82 (50.6) Multiple fractures, n (%) 31 (13.0) 10 (13.2) 21 (13) 0.967 Contralateral hip fracture, n (%) 22 (9.2) 9 (11.8) 13 (8) 0.343 Preoperative laboratory test Serum sodium, mmol/L 138.6 ± 5.0 139.0 ± 5.8 138.4 ± 4.6 0.353 Serum potassium, mmol/L 3.9 ± 0.5 3.9 ± 0.5 3.8 ± 0.5 0.648 Serum calcium, mmol/L 2.2 ± 0.2 2.2 ± 0.2 2.2 ± 0.1 0.934 Total albumin ** , g/L 68.5 ± 5.5 66.8 ± 5.5 69.3 ± 5.4 0.001 Albumin ** , g/L 38.8 ± 4.1 37.2 ± 4.0 39.5 ± 4.0 < 0.001 Absolute lymphocyte count, ×10⁹/L 1.1 ± 0.5 1.1 ± 0.5 1.2 ± 0.5 0.437 PNI ** 38.8 ± 4.1 37.2 ± 4.0 39.5 ± 4.0 < 0.001 Preoperative waiting time ** , hours 65.5 (39.0, 96.0) 88.0 (47.0, 120.0) 50.5 (33.1, 86.1) 90 hours ** , n (%) 71 (29.8) 37 (48.7) 34 (21) < 0.001 ASA classification ** , n (%) < 0.001 Class I 0 (0.0) 0 (0.0) 0 (0.0) Class II 25 (10.5) 1 (1.3) 24 (14.8) Class III 191 (80.6) 62 (82.7) 129 (79.6) Class IV 21 (8.9) 12 (16) 9 (5.6) Type of anesthesia, n (%) 0.419 General anesthesia 70 (29.4) 25 (32.9) 45 (27.8) Spinal anesthesia 168 (70.6) 51 (67.1) 117 (72.2) Surgical Methods, n (%) 0.337 Arthroplasty 111 (46.6) 32 (42.1) 79 (48.8) Internal fixation 127 (53.4) 44 (57.9) 83 (51.2) Operation time, hours 2.0 (1.5, 2.0) 2.0 (1.5, 2.0) 2.0 (1.5, 2.4) 0.386 Estimated blood loss, mL 100.0 (50.0, 200.0) 100.0 (50.0, 200.0) 100.0 (50.0, 200.0) 0.285 Postoperative complications, n (%) Venous Thromboembolism 79 (33.2) 26 (34.2) 53 (32.7) 0.819 Urinary tract infections ** 69 (29.0) 36 (47.4) 33 (20.4) < 0.001 Pulmonary infection ** 21 (8.8) 14 (18.4) 7 (4.3) < 0.001 Myocardial infarction 5 (2.1) 4 (5.3) 1 (0.6) 0.037 Stroke 11 (4.6) 6 (7.9) 5 (3.1) 0.110 Gastrointestinal bleeding 2 (0.8) 1 (1.3) 1 (0.6) 0.538 Incision infection 2 (0.8) 2 (2.6) 0 (0) 0.101 Continued Table 1 Hb on Day 1 post-operation, g/L 97.0 (87.0, 108.0) 94.0 (85.0, 103.8) 97.0 (88.0, 108.0) 0.127 ICU time ** , days 0.0 (0.0, 20.0) 17.8 (0.0, 24.2) 0.0 (0.0, 16.0) < 0.001 Length of stay ** , days 10.5 (8.0, 14.0) 13.0 (9.0, 16.0) 10.0 (8.0, 12.0) < 0.001 Abbreviations ： POD, postoperative delirium; BMI, Body mass index; CCI: Charlson comorbidity index; MNA scale, Mini nutritional assessment scale, "Nutritional status was assessed using the Mini Nutritional Assessment (MNA). Participants were classified into three groups based on MNA scores: malnourished (<17), at risk of malnutrition (17–23.5), and normal nutritional status (≥24)."; PNI, Prognostic Nutritional Index; ASA, American society of anesthesiologists; ICU, intensive care unit. *P‑value<0.05 is statistically significant, **P‑value<0.001 is highly significant. Patients with POD exhibited a statistically significant elevation in complication rates compared to the control cohort (47.4% vs. 20.4% for urinary tract infections, P<0.001; 18.4% vs. 4.3% for pulmonary infections, P<0.001), with infectious complications emerging as the most prominent manifestations. The delirium cohort demonstrated substantially prolonged critical care utilization (median ICU duration: 17.8 days vs. 0 days, P<0.001) and increased total hospitalization requirements (median hospital stay: 13.0 days vs. 10.0 days, P82 years; OR=3.34), prolonged preoperative waiting time (>90 hours; OR=3.57), frailty (OR=6.10), comorbidities (hypertension, respiratory diseases, stroke history), malnutrition (OR=12.68), and infectious complications (urinary tract infections: OR=3.52; pulmonary infections: OR=5.00). Notably, nutritional indices (PNI and total albumin), ASA classification, infectious complications, and CCI demonstrated statistical significance in univariate models (all P<0.05) but were excluded from the multivariate model. This exclusion likely reflects either collinearity with retained variables (e.g., frailty and age) or their potential role as secondary outcomes rather than independent etiological factors. Multivariable logistic regression (Table 3) revealed three independent risk factors after adjusting for confounders: advanced age (>82 years; adjusted OR=2.25), frailty (adjusted OR=2.40), and prolonged preoperative waiting time (>90 hours; adjusted OR=2.65). These findings underscore the multifactorial nature of POD, with geriatric vulnerability metrics and systemic delays in surgical intervention emerging as critical modifiable determinants. Table 2 Binary logistic regression models for variables associated with the risk of POD Variable OR 95% CI P -value Age> 82 years ** 3.34 (1.89~5.89) <0.001 Male 0.71 (0.37~1.33) 0.282 BMI, kg/m 2 0.95 (0.89~1.01) 0.111 Active Smoking 0.7 (0.18~2.66) 0.599 Alcohol abuse 0.42 (0.05~3.65) 0.430 Hypertension * 1.94 (1.03~3.63) 0.039 Heart disease 1.41 (0.81~2.47) 0.223 Diabetes mellitus 0.81 (0.45~1.48) 0.499 Kidney disease 1.07 (0.35~3.25) 0.904 Respiratory diseases * 2.56 (1.25~5.27) 0.011 History of stroke * 1.95 (1.08~3.5) 0.026 Mental disease 6.62 (0.68~64.69) 0.104 CCI ** 1.27 (1.13~1.43) <0.001 MNA scale At risk vs. normal nutrition * 2.42 (1.1~5.32) 0.028 Malnourished vs. normal nutrition ** 12.68 (4.09~39.37) <0.001 Frailty ** 6.1 (3.28~11.34) <0.001 Type of fracture Intertrochanteric vs. Femoral neck 1.53 (0.88~2.67) 0.135 Subtrochanteric vs. Femoral neck 0.89 (0.09~8.8) 0.917 Side right vs. left 0.92 (0.53~1.6) 0.779 Multiple fractures 1.02 (0.45~2.28) 0.967 Contralateral hip fracture 1.54 (0.63~3.78) 0.346 Internal fixation vs. Arthroplasty 1.31 (0.76~2.27) 0.337 Spinal anesthesia vs. General anesthesia 0.78 (0.44~1.41) 0.420 Total albumin * , g/L 0.92 (0.87~0.97) 0.002 Albumin ** , g/L 0.86 (0.8~0.93) <0.001 Absolute lymphocyte count, ×10⁹/L 0.81 (0.47~1.39) 0.436 PNI 0.86 (0.8~0.93) 90 hours ** 3.57 (1.98~6.43) <0.001 ASA classification Class III vs. Class II * 11.53 (1.53~87.19) 0.018 Class IV vs. Class II ** 32 (3.62~282.7) 0.002 Operation time, hours 0.79 (0.54~1.16) 0.235 Estimated blood loss, mL 1 (0.99~1) 0.194 Postoperative complications Venous Thromboembolism 1.07 (0.6~1.9) 0.819 Urinary tract infections ** 3.52 (1.95~6.35) <0.001 Continued Table 2 Pulmonary infection * 5 (1.93~12.98) 0.001 Myocardial infarction 8.94 (0.98~81.44) 0.052 Stroke 2.69 (0.79~9.11) 0.112 Gastrointestinal bleeding 2.15 (0.13~34.79) 0.591 Hb on Day 1 post-operation, g/L 0.98 (0.96~1) 0.082 Abbreviations ： POD, postoperative delirium; BMI, Body mass index; CCI: Charlson comorbidity index; MNA scale, Mini nutritional assessment scale, "Nutritional status was assessed using the Mini Nutritional Assessment (MNA). Participants were classified into three groups based on MNA scores: malnourished (<17), at risk of malnutrition (17–23.5), and normal nutritional status (≥24)."; PNI, Prognostic Nutritional Index; ASA, American society of anesthesiologists; ICU, intensive care unit. *P‑value<0.05 is statistically significant, **P‑value<0.001 is highly significant. Table 3 Logistic regression analysis relating to outcome POD Unadjusted Adjusted Variable OR (95% CI) P value OR (95% CI) P value (Intercept) 0.26 (0.17~0.40) 82 years * 3.34 (1.89~5.89) <0.001 2.25 (1.13~4.45) 0.020 Hypertension 1.94 (1.03~3.63) 0.039 Respiratory diseases 2.56 (1.25~5.27) 0.011 History of stroke 1.95 (1.08~3.50) 0.026 MNA scale At risk vs. normal nutrition 2.42 (1.10~5.32) 0.028 Malnourished vs. normal nutrition 12.68 (4.09~39.37) <0.001 CCI 1.27 (1.13~1.43) 90 hours ** 3.57 (1.98~6.43) <0.001 2.65 (1.3~5.37) 0.007 Frailty * 6.10 (3.28~11.34) <0.001 2.40 (1.08~5.32) 0.031 ASA classification Class III vs. Class II 11.53 (1.53~87.19) 0.018 Class IV vs. Class II 32.00 (3.62~282.70) 0.002 Continued Table 3 Urinary tract infections 3.52 (1.95~6.35) <0.001 Pulmonary infection 5.00 (1.93~12.98) 0.001 PNI 0.86 (0.80~0.93) <0.001 Total albumin, g/L 0.92 (0.87~0.97) 0.002 Abbreviations ： POD, postoperative delirium; CCI: Charlson comorbidity index; MNA scale, Mini nutritional assessment scale, "Nutritional status was assessed using the Mini Nutritional Assessment (MNA). Participants were classified into three groups based on MNA scores: malnourished (<17), at risk of malnutrition (17–23.5), and normal nutritional status (≥24)."; PNI, Prognostic Nutritional Index. *P‑value<0.05 is statistically significant, **P‑value 82 years; adjusted OR = 2.25), and prolonged preoperative waiting time (> 90 hours; adjusted OR = 2.65) emerging as independent predictors. The robust association between frailty and POD aligns with mechanistic evidence implicating diminished physiological reserve—manifested through impaired mitochondrial function and dysregulated neuroendocrine stress responses—in delirium pathogenesis[ 16 , 17 ]. Crucially, our temporal quantification of surgical delays advances existing literature: each incremental hour beyond the 90-hour threshold conferred a 165% escalation in delirium risk (OR = 2.65), underscoring the critical necessity for healthcare systems to implement expedited surgical protocols for this vulnerable demographic. These findings redefine geriatric perioperative care priorities, positioning biological resilience metrics and time-sensitive intervention as dual pillars for delirium prevention strategies. Our study conclusively demonstrates that preoperative frailty is a critical predictor of POD in elderly patients with hip fractures, aligning with prior findings[ 18 – 20 ]. In older hospitalized patients, preoperative frailty correlates with postoperative complications, including POD. Leung et al. reported an independent association between frailty and POD in non-cardiac surgery cohorts[ 21 ]. A recent meta-analysis of 15 cohorts (n = 3,250) revealed a 27.1% prevalence of preoperative frailty and a 15.8% incidence of POD, with frailty significantly elevating POD risk (OR = 3.23)[ 22 ]. These results resonate with studies by Shooka Esmaeeli et al.[ 23 ] (geriatric trauma cohort, n = 556, OR = 1.33) and Chen et al.[ 24 ] (total hip arthroplasty cohort, n = 383, OR = 3.31), both identifying frailty as an independent predictor of POD. Our adjusted OR of 2.65 corroborates these findings. This alignment underscores the mechanistic pathways through which frailty exacerbates neurocognitive risks. Frailty, defined by diminished physiological reserve and impaired stress response, predisposes patients to POD through interconnected mechanisms. Chronic inflammation, often termed "inflammatory aging," marked by elevated pro-inflammatory cytokines such as interleukin-6 and tumor necrosis factor-α, disrupts the integrity of the blood-brain barrier[ 25 , 26 ]. This inflammatory burden is compounded by mitochondrial dysfunction[ 27 ], which generates oxidative stress, triggers neuronal apoptosis, and impairs synaptic plasticity. Additionally, hypothalamic-pituitary-adrenal (HPA) axis dysregulation disrupts cortisol rhythm, contributing to cognitive fluctuations[ 28 ]. These insights highlight the potential of targeted frailty interventions, such as anti-inflammatory therapies or NAD + supplementation, as innovative strategies to mitigate the risk of POD[ 29 ]. Our multivariate analysis substantiates advanced age (> 82 years) as an independent predictor of POD (adjusted OR = 2.25), a finding that extends beyond chronological age to reflect multidimensional biological aging processes. This association likely arises from synergistic interactions between neurovascular senescence and diminished cholinergic resilience. Notably, from current researches, it can be inferred that aging-induced reductions in α7 nicotinic acetylcholine receptor density within the prefrontal cortex notably impair the integrity of attentional networks critical for delirium resistance [ 30 – 32 ]. The exponential risk escalation observed in octogenarians (POD incidence: 63.2% vs. 34.0% in non-POD cohort) delineates a critical biological threshold where cumulative oxidative stress intersects with blood-brain barrier permeability alterations to exacerbate neuroinflammatory cascades[ 33 , 34 ]. Mechanistically, age-related neurodegenerative remodeling[ 35 ]—characterized by cerebral hypoperfusion, neuronal attrition, and white matter hyperintensities—compromises cognitive reserve capacity, rendering geriatric patients disproportionately vulnerable to surgical stressors. These findings align with epidemiological evidence demonstrating that 53% of individuals aged 80–84 years harbor two or more comorbidities—particularly chronic inflammatory conditions—that potentiate cerebral microvascular dysfunction and neurocognitive instability[ 36 ]. Critically, our results corroborate the paradigm of gerosurgical vulnerability, emphasizing the imperative for age-stratified perioperative protocols to mitigate POD risk in hip fracture populations through targeted modulation of neuroinflammation and metabolic homeostasis. Numerous studies have established that an extended preoperative waiting time represents a crucial risk factor for POD[ 37 , 38 ]. Specifically, in hip fracture surgeries, a waiting time exceeding 36 hours significantly increases the risk of postoperative complications such as pneumonia, myocardial infarction, and heart failure within 30 days after the surgery[ 39 ]. Moreover, when the preoperative waiting time surpasses 90 hours, the risk of POD escalates by 2.65-fold. This finding aligns remarkably well with the clinical consensus on the urgency of hip fracture surgeries. The underlying association likely emerges through the concerted action of multiple intricate mechanisms. Firstly, surgical delay precipitates persistent pain and a stress response[ 38 ], thereby activating the HPA axis and leading to excessive glucocorticoid (GC) release[ 40 , 41 ]. Prolonged exposure to high GC levels can induce hippocampal neuronal damage via glucocorticoid receptor dysfunction and impaired neuroplasticity[ 41 ]. Animal studies have demonstrated that GCs can promote the generation of neuronal reactive oxygen species (ROS) and enhance Caspase-3 activity through the activation of the NLRP-1 inflammasome, exacerbating hippocampal neuronal injury[ 42 ]. Additionally, GCs impede hippocampus-dependent learning and memory functions by inhibiting the expression of brain-derived neurotrophic factor (BDNF) and reducing synaptic protein levels[ 43 – 45 ]. Intriguingly, research has shown that accelerated muscle catabolism caused by prolonged bed rest (> 72 hours) releases myogenic pro-inflammatory factors (such as myostatin), intensifying systemic inflammation[ 46 ]. In hip fracture patients, elevated postoperative serum levels of IL-6 and IL-8 are positively correlated with the risk of delirium[ 47 , 48 ]. Furthermore, dysbiosis of the gut microbiota leads to tryptophan metabolism disorders and increased blood-brain barrier permeability[ 49 ], enabling the accumulation of neurotoxic metabolites (such as quinolinic acid) in the brain. As an NMDA receptor agonist, quinolinic acid can induce glutamate excitotoxicity and neuronal apoptosis[ 50 ].​ Currently, there is a growing body of evidence advocating for the reduction of preoperative waiting time to mitigate the risk of POD [ 38 , 51 , 52 ]. Prolonged preoperative waiting time means to delayed surgery, and even a 24-hour delay has been identified as a predictor of minor medical postoperative complications, including delirium. In this study, delays exceeding 48 hours were found to be associated with severe medical complications[ 53 ]. Studies have demonstrated that fast-tracking and early surgery can reduce the incidence of postoperative complications such as delirium [ 54 ]. However, inconsistencies exist in the literature regarding the role of preoperative waiting time as a risk factor. While some studies have found a positive association between prolonged waiting time and increased POD risk[ 51 , 55 ], others have not established a significant link[ 56 , 57 ]. For instance, Lee et al. reported that preoperative waiting times exceeding 36 hours from emergency admission only affected the incidence of POD in patients with pre-existing dementia[ 58 ]. Similarly, Pioli et al. observed that preoperative waiting time influenced POD rates only in patients with mild-to-moderate preoperative cognitive impairment, whereas no significant effect was noted in cognitively healthy hip fracture patients[ 59 ]. Despite these findings, the optimal timing of surgery remains a subject of debate. Supporters of immediate surgery argue that it reduces the duration of bed rest for patients, thereby lowering the risk of postoperative complications[ 60 ]. In contrast, those advocating for delayed surgery maintain that postponing the procedure allows for sufficient time to optimize patient health, which can lead to a reduction in the likelihood of complications during the perioperative period[ 61 ]. For patients with inevitable surgical delays, preoperative prehabilitation (such as nutritional support and anti-inflammatory interventions) may partially counteract the adverse effects of waiting time by improving metabolic status and microbiota homeostasis. Neither the type of anesthesia (CSEA versus GA) nor the surgical procedure (joint replacement versus internal fixation) demonstrated a significant correlation with the incidence of POD, a finding that aligns with recent meta-analyses[ 62 ]. Although combined spinal-epidural anesthesia was predominantly used in both cohorts (67.1% in the POD group vs. 72.2% in the non-POD group), this distribution likely reflects institutional protocols rather than therapeutic benefits. These results imply that the susceptibility to delirium in elderly fracture patients may be more influenced by intrinsic physiological frailty than by differences in surgical procedures, underscoring the need for a shift toward comprehensive geriatric assessment programs. Our analysis further indicates that hip fracture type, preoperative medication, and fracture side are not significantly associated with POD. These findings suggest that these factors may not be critical determinants of delirium risk following hip fracture surgery. The strong correlation between infectious complications (particularly urinary and pulmonary infections) and POD (OR = 3.52–5.00) corroborates neuroinflammatory models of delirium. However, their exclusion from the multivariate model implies these infections may manifest as intermediary events along the delirium pathway rather than primary etiological drivers. This observation reinforces the need for mechanistic studies disentangling bidirectional relationships between systemic inflammation and neural dysfunction in POD. This study reports a significantly higher incidence of myocardial infarction in POD patients (5.3% vs. 0.6%), potentially driven by delirium-associated sympathetic hyperactivation and systemic inflammatory responses[ 63 ]. Animal experiments demonstrate that delirium-like states can induce mitochondrial uncoupling of oxidative phosphorylation in the myocardium, leading to acute cardiac dysfunction[ 27 ]. Additionally, our findings showed that POD patients had a prolonged intensive care unit (ICU) length of stay, consistent with previous studies[ 64 ], likely due to the need for longer mechanical ventilation, more complex care, and higher resource utilization. Compared to Hernandez et al.'s study on post-anesthesia care unit delirium, the higher POD rate (31.9% vs. 16.4%) in our cohort may reflect greater physiological frailty in hip fracture patients[ 65 ]. While both studies confirmed the risks of delayed surgery, our results highlighted frailty (rather than ASA classification) as an independent predictor, indicating that traditional anesthesia risk assessment tools like the ASA may underestimate the biological age differences in the elderly. This study has several limitations. First, the single-center design and the absence of inflammatory biomarker assessment (e.g., IL-6, CRP) could restrict the generalizability of the findings. Second, residual confounding from unmeasured variables, such as undiagnosed neuropathies, may still persist despite meticulous control of known confounders. Third, the observational nature of the study precludes definitive conclusions about the causal relationship between preoperative waiting time and the onset of delirium. Future research should incorporate multicenter studies that integrate single-cell transcriptomics and metabolomics to better define the molecular subtypes of POD. Additionally, randomized controlled trials evaluating interventions targeting frailty are essential to confirm their effectiveness in reducing the risk of POD. Conclusion In summary, this study reveals a high incidence of POD in elderly hip fracture patients and identifies advanced age, frailty, and prolonged preoperative waiting time as independent risk factors. These findings highlight the importance of optimizing preoperative assessment, accelerating surgical procedures, and implementing multidisciplinary interventions. While the study offers key insights, its single-center design and lack of inflammatory biomarker assessment may limit generalizability. Future research should involve multicenter studies, integrate omics technologies, and evaluate interventions targeting frailty to further clarify the molecular mechanisms and clinical management strategies for POD. Declarations Declarations Author contributions Yuzhi Wei, Haotian Wu and Huan Zhang conceptualized and designed the study, coordinated and supervised data collection, drafted the initial manuscript, and approved the final manuscript as submitted. Chunyu Feng, Ziheng Qi and Yujie Wang carried out the initial analyses, reviewed and revised the manuscript, and approved the final manuscript as submitted. Haotian Wu, Yuzhi Wei, and Huan Zhang designed the data collection, critically reviewed the manuscript, and approved the final manuscript as submitted. All authors approved the final manuscript as submitted and agree to be accountable for all aspects of the work. Ethical approval This study was approved by the Institutional Review Board of Beijing Tsinghua Changgung Hospital, School of Clinical Medicine, Tsinghua University (Approval No. 21277-0-01). The protocol was prospectively registered at ClinicalTrials.gov (NCT05246254). Conflicts of Interest The authors declare that there is no conflict of interest. Funding Sources This research was financially supported by the Beijing Municipal Administration of Hospitals Incubating Program [Approval No. PX2022037]. Data availability The corresponding author can provide the raw data of this study upon reasonable request. Author Contribution Yuzhi Wei, Haotian Wu and Huan Zhang conceptualized and designed the study, coordinated and supervised data collection, drafted the initial manuscript, and approved the final manuscript as submitted. Chunyu Feng, Ziheng Qi and Yujie Wang carried out the initial analyses, reviewed and revised the manuscript, and approved the final manuscript as submitted. Haotian Wu, Yuzhi Wei, and Huan Zhang designed the data collection, critically reviewed the manuscript, and approved the final manuscript as submitted. All authors approved the final manuscript as submitted and agree to be accountable for all aspects of the work. Acknowledgements We would like to thank all the patients who participated in this study. Data Availability The corresponding author can provide the raw data of this study upon reasonable request. References Swarbrick CJ, Partridge JSL (2022) Evidence-based strategies to reduce the incidence of postoperative delirium: a narrative review. 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J Cardiothorac Surg, 19:16. https://doi.org/10.1186/s13019-024-02485-5 Hernandez BA, Lindroth H, Rowley P, Boncyk C, Raz A, Gaskell A , et al (2017) Post-anaesthesia care unit delirium: incidence, risk factors and associated adverse outcomes. Br J Anaesth, 119:288-290. https://doi.org/10.1093/bja/aex197 Additional Declarations No competing interests reported. Cite Share Download PDF Status: Posted Version 1 posted You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. As a division of Research Square Company, we’re committed to making research communication faster, fairer, and more useful. We do this by developing innovative software and high quality services for the global research community. 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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-6635767","acceptedTermsAndConditions":true,"allowDirectSubmit":true,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":463249980,"identity":"4de3dd79-44e1-43f7-b1c5-ae5e91023ed9","order_by":0,"name":"Yuzhi Wei","email":"","orcid":"","institution":"Tsinghua University","correspondingAuthor":false,"prefix":"","firstName":"Yuzhi","middleName":"","lastName":"Wei","suffix":""},{"id":463249981,"identity":"6b8c2ea3-8f76-426f-8b8d-86dd43332ab5","order_by":1,"name":"Haotian Wu","email":"","orcid":"","institution":"Beijing Tsinghua Changgung Hospital","correspondingAuthor":false,"prefix":"","firstName":"Haotian","middleName":"","lastName":"Wu","suffix":""},{"id":463249982,"identity":"1f84646a-f0d1-4c66-9f2d-91a2cea06252","order_by":2,"name":"Chunyu Feng","email":"","orcid":"","institution":"Beijing Tsinghua Changgung Hospital","correspondingAuthor":false,"prefix":"","firstName":"Chunyu","middleName":"","lastName":"Feng","suffix":""},{"id":463249983,"identity":"521cb3d0-e9f1-437c-aa0d-776cf6d1ba55","order_by":3,"name":"Yujie Wang","email":"","orcid":"","institution":"Beijing Tsinghua Changgung Hospital","correspondingAuthor":false,"prefix":"","firstName":"Yujie","middleName":"","lastName":"Wang","suffix":""},{"id":463249984,"identity":"cf1ba6b7-b29c-4667-b66b-7087d690c476","order_by":4,"name":"Ziheng Qi","email":"","orcid":"","institution":"Tsinghua University","correspondingAuthor":false,"prefix":"","firstName":"Ziheng","middleName":"","lastName":"Qi","suffix":""},{"id":463249985,"identity":"aae7cd92-cafb-44e3-8fef-93398e11a1e5","order_by":5,"name":"Huan Zhang","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAABBElEQVRIiWNgGAWjYDACCSBmbAASzIztn39U2PDw8zcQq4W9+Rgzw5k0GckZB4jVwnMsjZmx7bCNQUMCfh3ys5ufPfy647C8uUSO2eOCM+d5DBgOMH74mINbC+OcY+bGsmcOG+6ckWNuPKPiNo85cwOz5MxtuLUwSySYSUu2HWbccCPHQILnzG0ey4YDbMy8eLSwSaR/A2mxB2vhbTvHY3AgAb8WHqAXJD+2HU7ccOZYmjRv2wHCWiQkcsqkGdvSkzccbz5sOONMMo/kjIPNeP0iPyN9m+TPNmvbDYcZGx98qLCz5+dvPvjhIx4t4CDgQeWDowk/YPxBUMkoGAWjYBSMaAAAgcVYCwAcItEAAAAASUVORK5CYII=","orcid":"","institution":"Beijing Tsinghua Changgung Hospital","correspondingAuthor":true,"prefix":"","firstName":"Huan","middleName":"","lastName":"Zhang","suffix":""}],"badges":[],"createdAt":"2025-05-10 15:53:11","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-6635767/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-6635767/v1","draftVersion":[],"editorialEvents":[],"editorialNote":"","failedWorkflow":false,"files":[{"id":83811386,"identity":"8c54f5bd-3394-431a-81b6-e29f735303b0","added_by":"auto","created_at":"2025-06-03 07:04:04","extension":"png","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":77078,"visible":true,"origin":"","legend":"\u003cp\u003eDepicts the flowchart of patient enrollment, with POD denoting postoperative delirium.\u003c/p\u003e","description":"","filename":"1.png","url":"https://assets-eu.researchsquare.com/files/rs-6635767/v1/7169c9ac61b3c0dceba0a2b0.png"},{"id":90520249,"identity":"2de65989-5cb0-47bb-9218-49873e7bac04","added_by":"auto","created_at":"2025-09-03 15:24:00","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":1005776,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-6635767/v1/053560ef-dd92-4049-9882-3dc9b268ed8b.pdf"}],"financialInterests":"No competing interests reported.","formattedTitle":"Risk Factors for Postoperative Delirium in Elderly Hip Fracture Patients: A Prospective Observational Analysis","fulltext":[{"header":"Introduction","content":"\u003cp\u003ePostoperative delirium (POD) represents a frequent neuropsychiatric complication in elderly hip fracture patients, typically occurring within 24\u0026ndash;72 hours after surgery and lasting for hours to days[\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e, \u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e]. The accelerated process of global aging has given rise to the prevalence of hip fractures. This vulnerable cohort, characterized by osteoporosis prevalence (69% in fragility fracture cohorts[\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e]), impaired ambulatory capacity, and complex multimorbidity profiles[\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e, \u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e], exhibits disproportionately high POD incidence rates (13%-70%)[\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e, \u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e]. POD is characterized by acute neurocognitive deterioration, with core manifestations including fluctuating consciousness, impaired attention (83% incidence[\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e]), and behavioral dysregulation. Clinical subtypes\u0026mdash;hyperactive (agitation/hallucinations), hypoactive (lethargy/apathy), and mixed\u0026mdash;exhibit distinct behavioral patterns. However, only 20.9% of delirium cases were systematically recorded, and the emergency department missed up to 75% of cases[\u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e], indicating significant diagnostic challenges.\u003c/p\u003e \u003cp\u003eThis neuropsychiatric complication exerts bidirectional strain on healthcare systems and patient outcomes. ICU stays and total hospitalization durations are significantly prolonged in patients with POD. Studies show that the ICU stay is prolonged by 36% (after risk adjustment) and total hospitalization is prolonged by 22% in patients with POD[\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e]. Longitudinal data confirm that POD prolongs rehabilitation duration by 6.5 days, amplifies the risk of secondary complications such as pressure ulcers[\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e, \u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e] and surgical site infections (OR\u0026thinsp;=\u0026thinsp;4.38) [\u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e], and is significantly associated with increased long-term mortality (OR\u0026thinsp;=\u0026thinsp;2.11, P\u0026thinsp;=\u0026thinsp;0.009, I\u003csup\u003e2\u003c/sup\u003e\u0026thinsp;=\u0026thinsp;62.5%)[\u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e].\u003c/p\u003e \u003cp\u003ePOD significantly impacts elderly patients with hip fractures, yet gaps remain in understanding its incidence and modifiable risk factors. Existing research has limitations in sample size and risk factor analysis, particularly regarding the complex interactions between risk factors and POD development. As hip fractures increase in aging populations, understanding POD in this vulnerable group becomes critical. This study aims to identify risk factors for POD and evaluate its association with clinical outcomes, including ICU stay, hospitalization duration, and postoperative complications. Findings may guide targeted preventive strategies to improve patient care and reduce healthcare burden.\u003c/p\u003e"},{"header":"Materials and methods","content":"\u003cp\u003eStudy Design\u003c/p\u003e \u003cp\u003e This prospective observational study adhered to the STROBE guidelines for observational research and was conducted at Beijing Tsinghua Chang Gung Hospital. It consecutively enrolled patients aged 60 years or older with imaging-confirmed hip fractures requiring surgery between January 2022 and November 2023. The protocol was approved by the institutional ethics committee (No. 21277-0-01), complied with the Declaration of Helsinki, and prospectively registered at ClinicalTrials.gov (NCT05246254). All participants provided witnessed written informed consent after trained researchers explained the study process. Data collection used standardized case report forms integrated with the electronic medical record system for real-time perioperative data verification.\u003c/p\u003e \u003cp\u003eInclusion and Exclusion Criteria\u003c/p\u003e \u003cp\u003eThis prospective cohort study enrolled 292 patients hospitalized for hip fractures between January 1, 2022, and November 30, 2023. Inclusion criteria were: participants aged 60 years or older; presence of hip fracture; signed informed consent form; American Society of Anesthesiologists (ASA) class I-IV; and surgery performed by a consistent anesthetic and surgical team. Exclusion criteria included: inability to provide informed consent; conservative treatment without surgery; duplicate fracture records; pre-existing cognitive impairment; inability to complete cognitive function tests; delirium during initial assessment; diagnosed psychiatric or substance use disorders; and incomplete or missing follow-up data. All patients received standardized preoperative preparation, anesthetic, and postoperative management. The primary objective of this study was to evaluate the incidence of POD.\u003c/p\u003e \u003cp\u003eStandardized Anesthetic Management Protocol\u003c/p\u003e \u003cp\u003eEnvironmental Control: Operating room temperature was strictly maintained between 20\u0026ndash;23\u0026deg;C, with relative humidity kept at 50\u0026ndash;60%; (ii) Temperature Management: A convection forced-air warming system and intravenous fluid warming device were systematically combined to maintain normal body temperature (36.5\u0026ndash;37.2\u0026deg;C); (iii) Venous Access and Monitoring: An 18G venous catheter was established in the upper limb for lactated Ringer's solution infusion (1\u0026ndash;5 mL/min). Continuous monitoring included three-lead electrocardiography, non-invasive oscillometric blood pressure, and pulse oximetry, with recordings of systolic blood pressure, heart rate, and oxygen saturation every 5 minutes; (iv) Neuraxial Anesthesia and Sedation: Senior anesthesiologists performed combined spinal-epidural anesthesia(CSEA)at the L2\u0026ndash;3/ L3\u0026ndash;4 interspace per standard protocol. With the patient in the right lateral position, a 16-gauge Tuohy needle was inserted via a paramedian approach. After confirming the epidural space using the loss-of-resistance technique, a 25-gauge Whitacre spinal needle was placed until cerebrospinal fluid returned, followed by intrathecal injection of 0.75% isobaric ropivacaine (1.8\u0026ndash;2.2 mL). Subsequently, an epidural catheter was advanced 3\u0026ndash;4 cm toward the cephalad direction. In the supine position, a standardized hip wedge was used to achieve 15\u0026deg; left uterine displacement. Dexmedetomidine was continuously infused (0.1\u0026ndash;0.3 \u0026micro;g/kg/h) to maintain Ramsay Sedation Scale scores of 2\u0026ndash;3; (v) General anesthesia (GA) was administered for patients with neuraxial anesthesia contraindications. Induction protocol included intravenous lidocaine (1.5 mg/kg), etomidate (0.2\u0026ndash;0.3 mg/kg) or propofol (2\u0026ndash;4 mg/kg), sufentanil (0.2\u0026ndash;0.4 \u0026micro;g/kg), and rocuronium (0.6 mg/kg). Post-intubation mechanical ventilation maintained P\u003csub\u003eET\u003c/sub\u003eCO2 35\u0026ndash;45 mmHg. Maintenance combined intravenous target-controlled infusion (propofol 2\u0026ndash;6 mg/kg/h or dexmedetomidine 0.1\u0026ndash;0.7 \u0026micro;g/kg/h) with remifentanil (0.04\u0026ndash;0.2\u0026micro;g/kg/min), supplemented by sevoflurane (1.0-2.5 vol%) to sustain bispectral index 40\u0026ndash;60. Hemodynamic targets included mean arterial pressure within 20% baseline and heart rate 55\u0026ndash;100 bpm. Perioperatively, patients received protocolized postanesthesia care unit (PACU) management incorporating ultrasound-guided catheter-based continuous femoral nerve block (CFNB) as part of a multimodal analgesic strategy. (vi) Advanced Monitoring: Invasive arterial catheterization was routinely performed in patients with ASA class\u0026thinsp;\u0026ge;\u0026thinsp;III or cardiopulmonary comorbidities; (vii) Hemodynamic Optimization: Goal-directed hemodynamic therapy was implemented to optimize volume status and maintain blood pressure within the ideal range.\u003c/p\u003e \u003cp\u003eObservation Indicators\u003c/p\u003e \u003cp\u003ePreoperative variables included age, gender, BMI, smoking history, alcohol abuse, comorbidities (hypertension, heart disease, diabetes mellitus, kidney diseases, history of stroke), and Charlson Comorbidity Index (CCI), with patients categorized into low (\u0026le;\u0026thinsp;2) and high (\u0026gt;\u0026thinsp;2) comorbidity burden groups. Nutritional status was assessed via the Mini Nutritional Assessment (MNA) scale, classifying participants as malnourished (\u0026lt;\u0026thinsp;17), at risk of malnutrition (17\u0026ndash;23.5), or with normal nutritional status (\u0026ge;\u0026thinsp;24). Frailty status, based on the Frailty Index (FI)[\u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e], divided participants into non-frail (FI\u0026thinsp;\u0026lt;\u0026thinsp;0.25) and frail (FI\u0026thinsp;\u0026ge;\u0026thinsp;0.25) status. Other preoperative factors included medication history, fracture type and side, presence of multiple fractures, history of contralateral hip fracture, preoperative laboratory test results, Prognostic Nutrition Index (PNI), preoperative waiting time (from admission to surgery), and ASA classification. (ii)Operative data comprised surgical method, anesthesia type, operation duration, and estimated blood loss. (iii)Postoperative factors covered complications (venous thromboembolism, urinary tract infections, pulmonary infections, myocardial infarction, stroke, gastrointestinal hemorrhage), hemoglobin level on postoperative day 1, ICU stay duration, and total hospital length of stay.\u003c/p\u003e \u003cp\u003eOutcome measures\u003c/p\u003e \u003cp\u003eThe Confusion Assessment Method (CAM)[\u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e14\u003c/span\u003e, \u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e15\u003c/span\u003e], the internationally validated gold-standard instrument for delirium detection, was systematically implemented with its four diagnostic pillars: (1) acute onset/fluctuating course, (2) inattention, (3) disorganized thinking, and (4) altered consciousness. Demonstrating exceptional psychometric properties (sensitivity: 95\u0026ndash;100%; specificity: 90\u0026ndash;95%), this protocol enabled standardized identification of both hyperactive and hypoactive delirium subtypes. Certified delirium assessments were conducted by a dual-qualified clinician (senior anesthesiologist holding neurology subspecialty certification) at critical postoperative intervals (POD 1, 2, 3, 5, 7) using time-series CAM evaluations to capture dynamic symptom trajectories. The rigorous assessment framework incorporated serial neurological examinations to differentiate transient cognitive changes from true delirium episodes.\u003c/p\u003e \u003cp\u003eOutcome indicators\u003c/p\u003e \u003cp\u003eThe primary outcome was the incidence of POD assessed using the CAM. Secondary outcomes included hospital length of stay, defined as days from admission to discharge, and ICU length of stay calculated from ICU admission to transfer and postoperative complications. Outcome assessors received standardized training in delirium evaluation protocols prior to data collection.\u003c/p\u003e \u003cdiv id=\"Sec3\" class=\"Section2\"\u003e \u003ch2\u003eStatistical analysis\u003c/h2\u003e \u003cp\u003eThe analytical cohort was stratified based on POD occurrence within 7 days. Continuous variables underwent normality assessment using the Kolmogorov-Smirnov test. Metabolic parameters (BMI, total protein, albumin, serum sodium/potassium/calcium) and nutritional indices (absolute lymphocyte count, prognostic nutritional index) demonstrating normal distribution were expressed as mean\u0026thinsp;\u0026plusmn;\u0026thinsp;SD. Surgical parameters (age, preoperative waiting time, operative duration, intraoperative blood loss) and care metrics (hospital/ICU stay) with non-normal distribution were reported as median (IQR). Categorical variables were presented as frequencies (percentages). Intergroup comparisons employed Student's t-test (parametric) or Wilcoxon rank-sum test (non-parametric) for continuous variables, and χ\u0026sup2; test or Fisher's exact test for categorical variables. Univariate logistic regression identified potential POD predictors. The multivariate model adjusted for: (1) demographic confounders (age\u0026thinsp;\u0026gt;\u0026thinsp;82 years, hypertension history); (2) comorbidities (respiratory diseases, stroke history, CCI); (3) perioperative factors (preoperative waiting time\u0026thinsp;\u0026gt;\u0026thinsp;90h, frailty status, ASA classification); (4) postoperative complications (urinary/pulmonary infections); 5) nutritional determinants (total protein, PNI). Adjusted odds ratios with 95% confidence intervals were calculated. All analyses were conducted using SPSS 27.0 (IBM Corp.) and Free Statistics 1.7.1 with α\u0026thinsp;=\u0026thinsp;0.05 for significance.\u003c/p\u003e \u003cp\u003eStatistical analysis was conducted using SPSS 27.0 (IBM, Armonk, NY, USA) and Free Statistics software (version 1.7.1) (\u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://www.clinicalscientists.cn/freestatistics/\u003c/span\u003e\u003cspan address=\"https://www.clinicalscientists.cn/freestatistics/\" targettype=\"URL\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e).\u003c/p\u003e \u003c/div\u003e\n\u003cp\u003eOutcomes\u003c/p\u003e\n\u003cp\u003eBetween January 2021 and November 2023, 292 patients underwent eligibility screening, with 238 meeting inclusion criteria (Figure 1). The prospective cohort demonstrated complete follow-up (100% retention) and full data completeness for all prespecified endpoints. No attrition or missing data occurred during the study period.\u003c/p\u003e\n\u003cp\u003eCharacteristics of the Study Population\u003c/p\u003e\n\u003cp\u003eThe study cohort comprised 238 geriatric hip fracture patients with mean age 79.0\u0026plusmn;8.7 years (females: 73.1%, n=174). POD occurred in 76 cases (31.9%). Comparative analysis revealed significant intergroup disparities in demographic and clinical profiles: POD patients demonstrated significantly higher prevalence of advanced age (\u0026gt;82 years: 63.2% vs 34.0%, P\u0026lt;0.001), preoperative frailty (76.3% vs 34.6%, OR=6.10, 95%CI 3.28-11.34), and malnutrition (22.4% vs 4.3%, P\u0026lt;0.001). Nutritional biomarkers showed marked deterioration in POD group - total albumin (66.8 \u0026plusmn; 5.5 vs 69.3 \u0026plusmn; 5.4 g/L, P\u0026lt;0.001) and PNI (37.2\u0026plusmn;4.0 vs 39.5\u0026plusmn;4.0, P\u0026lt;0.001). Comparative analysis of anesthetic modalities revealed a predominance of combined CSEA over GA in both POD and non-POD cohorts (67.1% vs. 32.9% and 72.2% vs. 27.8%, respectively), though these proportional differences lacked statistical significance (P\u0026gt;0.05). Similarly, no significant intergroup disparities emerged in operative strategy selection, with comparable utilization rates of arthroplasty versus internal fixation (46.6% vs. 53.4%, P=0.337) across study populations, as detailed in Table 1. These findings suggest that neither anesthetic modality nor surgical approach independently contributed to delirium risk stratification in this cohort.\u003c/p\u003e\n\u003cp\u003eTable 1. Comparison of baseline characteristics and other covariables between patients with and without postoperative delirium (POD).\u003c/p\u003e\n\u003ctable border=\"1\" cellspacing=\"0\" cellpadding=\"0\" width=\"100%\"\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 40px;\"\u003e\n \u003cp\u003e\u0026nbsp;Parameter\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 18px;\"\u003e\n \u003cp\u003eTotal\u0026nbsp;\u003c/p\u003e\n \u003cp\u003en = 238\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 17px;\"\u003e\n \u003cp\u003eWith POD\u003c/p\u003e\n \u003cp\u003en = 76\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 13px;\"\u003e\n \u003cp\u003eWith not POD\u003c/p\u003e\n \u003cp\u003en = 162\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 9px;\"\u003e\n \u003cp\u003e\u003cem\u003e\u0026nbsp;\u003c/em\u003e\u003c/p\u003e\n \u003cp\u003e\u003cem\u003eP\u0026nbsp;\u003c/em\u003evalue\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 40px;\"\u003e\n \u003cp\u003eAge\u003csup\u003e**\u003c/sup\u003e, years\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 18px;\"\u003e\n \u003cp\u003e79.0 \u0026plusmn; 8.7\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 17px;\"\u003e\n \u003cp\u003e82.5 \u0026plusmn; 7.8\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 13px;\"\u003e\n \u003cp\u003e77.3 \u0026plusmn; 8.6\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 9px;\"\u003e\n \u003cp\u003e\u0026lt; 0.001\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 40px;\"\u003e\n \u003cp\u003eGender, n (%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 18px;\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 17px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 13px;\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 9px;\"\u003e\n \u003cp\u003e0.281\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 40px;\"\u003e\n \u003cp\u003eFemale\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 18px;\"\u003e\n \u003cp\u003e174 (73.1)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 17px;\"\u003e\n \u003cp\u003e59 (77.6)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 13px;\"\u003e\n \u003cp\u003e115 (71.0)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 9px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 40px;\"\u003e\n \u003cp\u003eMale\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 18px;\"\u003e\n \u003cp\u003e64 (26.9)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 17px;\"\u003e\n \u003cp\u003e17 (22.4)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 13px;\"\u003e\n \u003cp\u003e47 (29.0)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 9px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 40px;\"\u003e\n \u003cp\u003eBMI, kg/m\u003csup\u003e2\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 18px;\"\u003e\n \u003cp\u003e24.0 \u0026plusmn; 4.4\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 17px;\"\u003e\n \u003cp\u003e23.3 \u0026plusmn; 4.7\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 13px;\"\u003e\n \u003cp\u003e24.3 \u0026plusmn; 4.3\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 9px;\"\u003e\n \u003cp\u003e0.110\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 40px;\"\u003e\n \u003cp\u003eActive smoking, n (%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 18px;\"\u003e\n \u003cp\u003e12 (5.0)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 17px;\"\u003e\n \u003cp\u003e3 (3.9)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 13px;\"\u003e\n \u003cp\u003e9 (5.6)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 9px;\"\u003e\n \u003cp\u003e0.757\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 40px;\"\u003e\n \u003cp\u003eAlcohol abuse, n (%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 18px;\"\u003e\n \u003cp\u003e6 (2.5)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 17px;\"\u003e\n \u003cp\u003e1 (1.3)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 13px;\"\u003e\n \u003cp\u003e5 (3.1)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 9px;\"\u003e\n \u003cp\u003e0.667\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 40px;\"\u003e\n \u003cp\u003eComorbidity, n (%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 18px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 17px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 13px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 9px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 40px;\"\u003e\n \u003cp\u003eHypertension\u003csup\u003e*\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 18px;\"\u003e\n \u003cp\u003e163 (68.5)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 17px;\"\u003e\n \u003cp\u003e59 (77.6)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 13px;\"\u003e\n \u003cp\u003e104 (64.2)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 9px;\"\u003e\n \u003cp\u003e0.038\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 40px;\"\u003e\n \u003cp\u003eHeart disease\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 18px;\"\u003e\n \u003cp\u003e90 (37.8)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 17px;\"\u003e\n \u003cp\u003e33 (43.4)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 13px;\"\u003e\n \u003cp\u003e57 (35.2)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 9px;\"\u003e\n \u003cp\u003e0.222\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 40px;\"\u003e\n \u003cp\u003eDiabetes mellitus\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 18px;\"\u003e\n \u003cp\u003e76 (31.9)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 17px;\"\u003e\n \u003cp\u003e22 (28.9)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 13px;\"\u003e\n \u003cp\u003e54 (33.3)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 9px;\"\u003e\n \u003cp\u003e0.499\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 40px;\"\u003e\n \u003cp\u003eKidney disease\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 18px;\"\u003e\n \u003cp\u003e15 (6.3)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 17px;\"\u003e\n \u003cp\u003e5 (6.6)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 13px;\"\u003e\n \u003cp\u003e10 (6.2)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 9px;\"\u003e\n \u003cp\u003e1.000\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 40px;\"\u003e\n \u003cp\u003eRespiratory diseases\u003csup\u003e*\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 18px;\"\u003e\n \u003cp\u003e178 (74.8)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 17px;\"\u003e\n \u003cp\u003e65 (85.5)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 13px;\"\u003e\n \u003cp\u003e113 (69.8)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 9px;\"\u003e\n \u003cp\u003e0.009\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 40px;\"\u003e\n \u003cp\u003eHistory of stroke\u003csup\u003e*\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 18px;\"\u003e\n \u003cp\u003e68 (28.6)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 17px;\"\u003e\n \u003cp\u003e29 (38.2)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 13px;\"\u003e\n \u003cp\u003e39 (24.1)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 9px;\"\u003e\n \u003cp\u003e0.025\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 40px;\"\u003e\n \u003cp\u003eCCI\u003csup\u003e**\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 18px;\"\u003e\n \u003cp\u003e5.0 (4.0, 6.0)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 17px;\"\u003e\n \u003cp\u003e6.0 (5.0, 7.0)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 13px;\"\u003e\n \u003cp\u003e4.0 (3.0, 5.0)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 9px;\"\u003e\n \u003cp\u003e\u0026lt; 0.001\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 40px;\"\u003e\n \u003cp\u003eMNA scale\u003csup\u003e**\u003c/sup\u003e, n (%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 18px;\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 17px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 13px;\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 9px;\"\u003e\n \u003cp\u003e\u0026lt; 0.001\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 40px;\"\u003e\n \u003cp\u003eNormal nutrition\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 18px;\"\u003e\n \u003cp\u003e56 (23.5)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 17px;\"\u003e\n \u003cp\u003e9 (11.8)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 13px;\"\u003e\n \u003cp\u003e47 (29)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 9px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 40px;\"\u003e\n \u003cp\u003eAt risk\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 18px;\"\u003e\n \u003cp\u003e158 (66.4)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 17px;\"\u003e\n \u003cp\u003e50 (65.8)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 13px;\"\u003e\n \u003cp\u003e108 (66.7)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 9px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 40px;\"\u003e\n \u003cp\u003eMalnourished\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 18px;\"\u003e\n \u003cp\u003e24 (10.1)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 17px;\"\u003e\n \u003cp\u003e17 (22.4)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 13px;\"\u003e\n \u003cp\u003e7 (4.3)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 9px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 40px;\"\u003e\n \u003cp\u003eFrailty\u003csup\u003e**\u003c/sup\u003e, n (%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 18px;\"\u003e\n \u003cp\u003e114 (47.9)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 17px;\"\u003e\n \u003cp\u003e58 (76.3)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 13px;\"\u003e\n \u003cp\u003e56 (34.6)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 9px;\"\u003e\n \u003cp\u003e\u0026lt; 0.001\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 40px;\"\u003e\n \u003cp\u003eMedication History, n (%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 18px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 17px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 13px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 9px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 40px;\"\u003e\n \u003cp\u003eHormone\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 18px;\"\u003e\n \u003cp\u003e11 (4.6)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 17px;\"\u003e\n \u003cp\u003e3 (3.9)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 13px;\"\u003e\n \u003cp\u003e8 (4.9)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 9px;\"\u003e\n \u003cp\u003e1.000\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 40px;\"\u003e\n \u003cp\u003eZoledronic acid\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 18px;\"\u003e\n \u003cp\u003e5 (2.1)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 17px;\"\u003e\n \u003cp\u003e0 (0)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 13px;\"\u003e\n \u003cp\u003e5 (3.1)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 9px;\"\u003e\n \u003cp\u003e0.180\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 40px;\"\u003e\n \u003cp\u003eType of fracture, n (%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 18px;\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 17px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 13px;\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 9px;\"\u003e\n \u003cp\u003e0.286\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 40px;\"\u003e\n \u003cp\u003eFemoral neck\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 18px;\"\u003e\n \u003cp\u003e128 (54.2)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 17px;\"\u003e\n \u003cp\u003e35 (47.3)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 13px;\"\u003e\n \u003cp\u003e93 (57.4)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 9px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n\u003c/table\u003e\n\u003cp\u003e\u003cstrong\u003eContinued Table 1\u003c/strong\u003e\u003c/p\u003e\n\u003ctable border=\"1\" cellspacing=\"0\" cellpadding=\"0\" width=\"100%\"\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 28.8524%;\"\u003e\n \u003cp\u003eIntertrochanteric\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 25.6078%;\"\u003e\n \u003cp\u003e104 (44.1)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 15.5607%;\"\u003e\n \u003cp\u003e38 (51.4)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 9.0669%;\"\u003e\n \u003cp\u003e66 (40.7)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 8.6993%;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 28.8524%;\"\u003e\n \u003cp\u003eSubtrochanteric\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 25.6078%;\"\u003e\n \u003cp\u003e4 (1.7)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 15.5607%;\"\u003e\n \u003cp\u003e1 (1.4)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 9.0669%;\"\u003e\n \u003cp\u003e3 (1.9)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 8.6993%;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 28.8524%;\"\u003e\n \u003cp\u003eSide, n (%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 25.6078%;\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 15.5607%;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 9.0669%;\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 8.6993%;\"\u003e\n \u003cp\u003e0.779\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 28.8524%;\"\u003e\n \u003cp\u003eLeft\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 25.6078%;\"\u003e\n \u003cp\u003e118 (50.0)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 15.5607%;\"\u003e\n \u003cp\u003e38 (51.4)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 9.0669%;\"\u003e\n \u003cp\u003e80 (49.4)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 8.6993%;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 28.8524%;\"\u003e\n \u003cp\u003eRight\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 25.6078%;\"\u003e\n \u003cp\u003e118 (50.0)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 15.5607%;\"\u003e\n \u003cp\u003e36 (48.6)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 9.0669%;\"\u003e\n \u003cp\u003e82 (50.6)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 8.6993%;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 28.8524%;\"\u003e\n \u003cp\u003eMultiple fractures, n (%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 25.6078%;\"\u003e\n \u003cp\u003e31 (13.0)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 15.5607%;\"\u003e\n \u003cp\u003e10 (13.2)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 9.0669%;\"\u003e\n \u003cp\u003e21 (13)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 8.6993%;\"\u003e\n \u003cp\u003e0.967\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 28.8524%;\"\u003e\n \u003cp\u003eContralateral hip fracture, n (%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 25.6078%;\"\u003e\n \u003cp\u003e22 (9.2)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 15.5607%;\"\u003e\n \u003cp\u003e9 (11.8)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 9.0669%;\"\u003e\n \u003cp\u003e13 (8)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 8.6993%;\"\u003e\n \u003cp\u003e0.343\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 28.8524%;\"\u003e\n \u003cp\u003ePreoperative laboratory test\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 25.6078%;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 15.5607%;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 9.0669%;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 8.6993%;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 28.8524%;\"\u003e\n \u003cp\u003eSerum sodium, mmol/L\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 25.6078%;\"\u003e\n \u003cp\u003e138.6 \u0026plusmn; 5.0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 15.5607%;\"\u003e\n \u003cp\u003e139.0 \u0026plusmn; 5.8\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 9.0669%;\"\u003e\n \u003cp\u003e138.4 \u0026plusmn; 4.6\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 8.6993%;\"\u003e\n \u003cp\u003e0.353\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 28.8524%;\"\u003e\n \u003cp\u003eSerum potassium, mmol/L\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 25.6078%;\"\u003e\n \u003cp\u003e3.9 \u0026plusmn; 0.5\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 15.5607%;\"\u003e\n \u003cp\u003e3.9 \u0026plusmn; 0.5\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 9.0669%;\"\u003e\n \u003cp\u003e3.8 \u0026plusmn; 0.5\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 8.6993%;\"\u003e\n \u003cp\u003e0.648\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 28.8524%;\"\u003e\n \u003cp\u003eSerum calcium, mmol/L\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 25.6078%;\"\u003e\n \u003cp\u003e2.2 \u0026plusmn; 0.2\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 15.5607%;\"\u003e\n \u003cp\u003e2.2 \u0026plusmn; 0.2\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 9.0669%;\"\u003e\n \u003cp\u003e2.2 \u0026plusmn; 0.1\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 8.6993%;\"\u003e\n \u003cp\u003e0.934\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 28.8524%;\"\u003e\n \u003cp\u003eTotal albumin\u003csup\u003e**\u003c/sup\u003e, g/L\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 25.6078%;\"\u003e\n \u003cp\u003e68.5 \u0026plusmn; 5.5\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 15.5607%;\"\u003e\n \u003cp\u003e66.8 \u0026plusmn; 5.5\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 9.0669%;\"\u003e\n \u003cp\u003e69.3 \u0026plusmn; 5.4\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 8.6993%;\"\u003e\n \u003cp\u003e0.001\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 28.8524%;\"\u003e\n \u003cp\u003eAlbumin\u003csup\u003e**\u003c/sup\u003e, g/L\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 25.6078%;\"\u003e\n \u003cp\u003e38.8 \u0026plusmn; 4.1\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 15.5607%;\"\u003e\n \u003cp\u003e37.2 \u0026plusmn; 4.0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 9.0669%;\"\u003e\n \u003cp\u003e39.5 \u0026plusmn; 4.0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 8.6993%;\"\u003e\n \u003cp\u003e\u0026lt; 0.001\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 28.8524%;\"\u003e\n \u003cp\u003eAbsolute lymphocyte count, \u0026times;10⁹/L\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 25.6078%;\"\u003e\n \u003cp\u003e1.1 \u0026plusmn; 0.5\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 15.5607%;\"\u003e\n \u003cp\u003e1.1 \u0026plusmn; 0.5\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 9.0669%;\"\u003e\n \u003cp\u003e1.2 \u0026plusmn; 0.5\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 8.6993%;\"\u003e\n \u003cp\u003e0.437\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 28.8524%;\"\u003e\n \u003cp\u003ePNI\u003csup\u003e**\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 25.6078%;\"\u003e\n \u003cp\u003e38.8 \u0026plusmn; 4.1\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 15.5607%;\"\u003e\n \u003cp\u003e37.2 \u0026plusmn; 4.0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 9.0669%;\"\u003e\n \u003cp\u003e39.5 \u0026plusmn; 4.0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 8.6993%;\"\u003e\n \u003cp\u003e\u0026lt; 0.001\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 28.8524%;\"\u003e\n \u003cp\u003ePreoperative waiting time\u003csup\u003e**\u003c/sup\u003e, hours\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 25.6078%;\"\u003e\n \u003cp\u003e65.5 (39.0, 96.0)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 15.5607%;\"\u003e\n \u003cp\u003e88.0 (47.0, 120.0)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 9.0669%;\"\u003e\n \u003cp\u003e50.5 (33.1, 86.1)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 8.6993%;\"\u003e\n \u003cp\u003e\u0026lt; 0.001\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 28.8524%;\"\u003e\n \u003cp\u003ePreoperative waiting time\u0026gt; 90 hours\u003csup\u003e**\u003c/sup\u003e, n (%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 25.6078%;\"\u003e\n \u003cp\u003e71 (29.8)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 15.5607%;\"\u003e\n \u003cp\u003e37 (48.7)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 9.0669%;\"\u003e\n \u003cp\u003e34 (21)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 8.6993%;\"\u003e\n \u003cp\u003e\u0026lt; 0.001\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 28.8524%;\"\u003e\n \u003cp\u003eASA classification\u003csup\u003e**\u003c/sup\u003e, n (%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 25.6078%;\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 15.5607%;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 9.0669%;\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 8.6993%;\"\u003e\n \u003cp\u003e\u0026lt; 0.001\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 28.8524%;\"\u003e\n \u003cp\u003eClass I\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 25.6078%;\"\u003e\n \u003cp\u003e0 (0.0)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 15.5607%;\"\u003e\n \u003cp\u003e0 (0.0)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 9.0669%;\"\u003e\n \u003cp\u003e0 (0.0)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 8.6993%;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 28.8524%;\"\u003e\n \u003cp\u003eClass II\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 25.6078%;\"\u003e\n \u003cp\u003e25 (10.5)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 15.5607%;\"\u003e\n \u003cp\u003e1 (1.3)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 9.0669%;\"\u003e\n \u003cp\u003e24 (14.8)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 8.6993%;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 28.8524%;\"\u003e\n \u003cp\u003eClass III\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 25.6078%;\"\u003e\n \u003cp\u003e191 (80.6)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 15.5607%;\"\u003e\n \u003cp\u003e62 (82.7)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 9.0669%;\"\u003e\n \u003cp\u003e129 (79.6)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 8.6993%;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 28.8524%;\"\u003e\n \u003cp\u003eClass IV\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 25.6078%;\"\u003e\n \u003cp\u003e21 (8.9)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 15.5607%;\"\u003e\n \u003cp\u003e12 (16)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 9.0669%;\"\u003e\n \u003cp\u003e9 (5.6)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 8.6993%;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 28.8524%;\"\u003e\n \u003cp\u003eType of anesthesia, n (%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 25.6078%;\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 15.5607%;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 9.0669%;\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 8.6993%;\"\u003e\n \u003cp\u003e0.419\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 28.8524%;\"\u003e\n \u003cp\u003eGeneral anesthesia\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 25.6078%;\"\u003e\n \u003cp\u003e70 (29.4)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 15.5607%;\"\u003e\n \u003cp\u003e25 (32.9)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 9.0669%;\"\u003e\n \u003cp\u003e45 (27.8)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 8.6993%;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 28.8524%;\"\u003e\n \u003cp\u003eSpinal anesthesia\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 25.6078%;\"\u003e\n \u003cp\u003e168 (70.6)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 15.5607%;\"\u003e\n \u003cp\u003e51 (67.1)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 9.0669%;\"\u003e\n \u003cp\u003e117 (72.2)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 8.6993%;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 28.8524%;\"\u003e\n \u003cp\u003eSurgical Methods, n (%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 25.6078%;\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 15.5607%;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 9.0669%;\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 8.6993%;\"\u003e\n \u003cp\u003e0.337\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 28.8524%;\"\u003e\n \u003cp\u003eArthroplasty\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 25.6078%;\"\u003e\n \u003cp\u003e111 (46.6)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 15.5607%;\"\u003e\n \u003cp\u003e32 (42.1)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 9.0669%;\"\u003e\n \u003cp\u003e79 (48.8)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 8.6993%;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 28.8524%;\"\u003e\n \u003cp\u003eInternal fixation\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 25.6078%;\"\u003e\n \u003cp\u003e127 (53.4)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 15.5607%;\"\u003e\n \u003cp\u003e44 (57.9)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 9.0669%;\"\u003e\n \u003cp\u003e83 (51.2)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 8.6993%;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 28.8524%;\"\u003e\n \u003cp\u003eOperation time, hours\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 25.6078%;\"\u003e\n \u003cp\u003e2.0 (1.5, 2.0)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 15.5607%;\"\u003e\n \u003cp\u003e2.0 (1.5, 2.0)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 9.0669%;\"\u003e\n \u003cp\u003e2.0 (1.5, 2.4)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 8.6993%;\"\u003e\n \u003cp\u003e0.386\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 28.8524%;\"\u003e\n \u003cp\u003eEstimated blood loss, mL\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 25.6078%;\"\u003e\n \u003cp\u003e100.0 (50.0, 200.0)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 15.5607%;\"\u003e\n \u003cp\u003e100.0 (50.0, 200.0)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 9.0669%;\"\u003e\n \u003cp\u003e100.0 (50.0, 200.0)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 8.6993%;\"\u003e\n \u003cp\u003e0.285\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 28.8524%;\"\u003e\n \u003cp\u003ePostoperative complications, n (%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 25.6078%;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 15.5607%;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 9.0669%;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 8.6993%;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 28.8524%;\"\u003e\n \u003cp\u003eVenous Thromboembolism\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 25.6078%;\"\u003e\n \u003cp\u003e79 (33.2)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 15.5607%;\"\u003e\n \u003cp\u003e26 (34.2)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 9.0669%;\"\u003e\n \u003cp\u003e53 (32.7)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 8.6993%;\"\u003e\n \u003cp\u003e0.819\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 28.8524%;\"\u003e\n \u003cp\u003eUrinary tract infections\u003csup\u003e**\u003c/sup\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 25.6078%;\"\u003e\n \u003cp\u003e69 (29.0)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 15.5607%;\"\u003e\n \u003cp\u003e36 (47.4)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 9.0669%;\"\u003e\n \u003cp\u003e33 (20.4)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 8.6993%;\"\u003e\n \u003cp\u003e\u0026lt; 0.001\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 28.8524%;\"\u003e\n \u003cp\u003ePulmonary infection\u003csup\u003e**\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 25.6078%;\"\u003e\n \u003cp\u003e21 (8.8)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 15.5607%;\"\u003e\n \u003cp\u003e14 (18.4)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 9.0669%;\"\u003e\n \u003cp\u003e7 (4.3)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 8.6993%;\"\u003e\n \u003cp\u003e\u0026lt; 0.001\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 28.8524%;\"\u003e\n \u003cp\u003eMyocardial infarction\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 25.6078%;\"\u003e\n \u003cp\u003e5 (2.1)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 15.5607%;\"\u003e\n \u003cp\u003e4 (5.3)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 9.0669%;\"\u003e\n \u003cp\u003e1 (0.6)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 8.6993%;\"\u003e\n \u003cp\u003e0.037\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 28.8524%;\"\u003e\n \u003cp\u003eStroke\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 25.6078%;\"\u003e\n \u003cp\u003e11 (4.6)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 15.5607%;\"\u003e\n \u003cp\u003e6 (7.9)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 9.0669%;\"\u003e\n \u003cp\u003e5 (3.1)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 8.6993%;\"\u003e\n \u003cp\u003e0.110\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 21.5645%;\"\u003e\n \u003cp\u003eGastrointestinal bleeding\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 25.6078%;\"\u003e\u003cbr\u003e2 (0.8)\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 15.5607%;\"\u003e\u003cbr\u003e1 (1.3)\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 9.0669%;\"\u003e\u003cbr\u003e1 (0.6)\u003cbr\u003e\u003c/td\u003e\n \u003ctd style=\"width: 8.6993%;\"\u003e\n \u003cp\u003e\u0026nbsp;0.538\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 21.5645%;\"\u003e\n \u003cp\u003eIncision infection\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 25.6078%;\"\u003e\u003cbr\u003e2 (0.8)\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 15.5607%;\"\u003e\u003cbr\u003e2 (2.6)\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 9.0669%;\"\u003e\u003cbr\u003e0 (0)\u003cbr\u003e\u003c/td\u003e\n \u003ctd style=\"width: 8.6993%;\"\u003e\n \u003cp\u003e\u0026nbsp;0.101\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n\u003c/table\u003e\n\u003cp\u003e\u003cstrong\u003eContinued Table 1\u003c/strong\u003e\u003c/p\u003e\n\u003ctable border=\"1\" cellspacing=\"0\" cellpadding=\"0\" width=\"99%\"\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 40px;\"\u003e\n \u003cp\u003eHb on Day 1 post-operation, g/L\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 19px;\"\u003e\n \u003cp\u003e97.0 (87.0, 108.0)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 12px;\"\u003e\n \u003cp\u003e94.0 (85.0, 103.8)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 19px;\"\u003e\n \u003cp\u003e97.0 (88.0, 108.0)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 9px;\"\u003e\n \u003cp\u003e0.127\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 40px;\"\u003e\n \u003cp\u003eICU time\u003csup\u003e**\u003c/sup\u003e, days\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 19px;\"\u003e\n \u003cp\u003e0.0 (0.0, 20.0)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 12px;\"\u003e\n \u003cp\u003e17.8 (0.0, 24.2)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 19px;\"\u003e\n \u003cp\u003e0.0 (0.0, 16.0)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 9px;\"\u003e\n \u003cp\u003e\u0026lt; 0.001\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 40px;\"\u003e\n \u003cp\u003eLength of stay\u003csup\u003e**\u003c/sup\u003e, days\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 19px;\"\u003e\n \u003cp\u003e10.5 (8.0, 14.0)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 12px;\"\u003e\n \u003cp\u003e13.0 (9.0, 16.0)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 19px;\"\u003e\n \u003cp\u003e10.0 (8.0, 12.0)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 9px;\"\u003e\n \u003cp\u003e\u0026lt; 0.001\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n\u003c/table\u003e\n\u003cp\u003e\u003cstrong\u003eAbbreviations\u003c/strong\u003e\u003cstrong\u003e：\u003c/strong\u003e\u003cstrong\u003ePOD, postoperative delirium; BMI, Body mass index;\u0026nbsp;\u003c/strong\u003eCCI: Charlson comorbidity index; MNA scale, Mini nutritional assessment scale, \u0026quot;Nutritional status was assessed using the Mini Nutritional Assessment (MNA). Participants were classified into three groups based on MNA scores: malnourished (\u0026lt;17), at risk of malnutrition (17\u0026ndash;23.5), and normal nutritional status (\u0026ge;24).\u0026quot;;\u0026nbsp;PNI, Prognostic Nutritional Index; ASA, American society of anesthesiologists; ICU, intensive care unit.\u003c/p\u003e\n\u003cp\u003e*P‑value\u0026lt;0.05 is statistically significant, **P‑value\u0026lt;0.001 is highly significant.\u003c/p\u003e\n\u003cp\u003ePatients with POD exhibited a statistically significant elevation in complication rates compared to the control cohort (47.4% vs. 20.4% for urinary tract infections, P\u0026lt;0.001; 18.4% vs. 4.3% for pulmonary infections, P\u0026lt;0.001), with infectious complications emerging as the most prominent manifestations. The delirium cohort demonstrated substantially prolonged critical care utilization (median ICU duration: 17.8 days vs. 0 days, P\u0026lt;0.001) and increased total hospitalization requirements (median hospital stay: 13.0 days vs. 10.0 days, P\u0026lt;0.001), reflecting greater healthcare resource consumption.\u003c/p\u003e\n\u003cp\u003eUnivariate analysis (Table 2) identified multiple significant predictors of POD, including advanced age (\u0026gt;82 years; OR=3.34), prolonged preoperative waiting time (\u0026gt;90 hours; OR=3.57), frailty (OR=6.10), comorbidities (hypertension, respiratory diseases, stroke history), malnutrition (OR=12.68), and infectious complications (urinary tract infections: OR=3.52; pulmonary infections: OR=5.00). Notably, nutritional indices (PNI and total albumin), ASA classification, infectious complications, and CCI demonstrated statistical significance in univariate models (all P\u0026lt;0.05) but were excluded from the multivariate model. This exclusion likely reflects either collinearity with retained variables (e.g., frailty and age) or their potential role as secondary outcomes rather than independent etiological factors. Multivariable logistic regression (Table 3) revealed three independent risk factors after adjusting for confounders: advanced age (\u0026gt;82 years; adjusted OR=2.25), frailty (adjusted OR=2.40), and prolonged preoperative waiting time (\u0026gt;90 hours; adjusted OR=2.65). These findings underscore the multifactorial nature of POD, with geriatric vulnerability metrics and systemic delays in surgical intervention emerging as critical modifiable determinants.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eTable 2\u003c/strong\u003e Binary logistic regression models for variables associated with the risk of POD\u003c/p\u003e\n\u003ctable border=\"1\" cellspacing=\"0\" cellpadding=\"0\" width=\"100%\"\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 48px;\"\u003e\n \u003cp\u003eVariable\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 34px;\"\u003e\n \u003cp\u003eOR 95% CI\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 17px;\"\u003e\n \u003cp\u003e\u003cem\u003eP\u003c/em\u003e-value\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 48px;\"\u003e\n \u003cp\u003eAge\u0026gt; 82 years\u003csup\u003e**\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 34px;\"\u003e\n \u003cp\u003e3.34 (1.89~5.89)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 17px;\"\u003e\n \u003cp\u003e\u0026lt;0.001\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 48px;\"\u003e\n \u003cp\u003eMale\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 34px;\"\u003e\n \u003cp\u003e0.71 (0.37~1.33)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 17px;\"\u003e\n \u003cp\u003e0.282\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 48px;\"\u003e\n \u003cp\u003eBMI, kg/m\u003csup\u003e2\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 34px;\"\u003e\n \u003cp\u003e0.95 (0.89~1.01)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 17px;\"\u003e\n \u003cp\u003e0.111\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 48px;\"\u003e\n \u003cp\u003eActive Smoking\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 34px;\"\u003e\n \u003cp\u003e0.7 (0.18~2.66)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 17px;\"\u003e\n \u003cp\u003e0.599\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 48px;\"\u003e\n \u003cp\u003eAlcohol abuse\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 34px;\"\u003e\n \u003cp\u003e0.42 (0.05~3.65)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 17px;\"\u003e\n \u003cp\u003e0.430\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 48px;\"\u003e\n \u003cp\u003eHypertension\u003csup\u003e*\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 34px;\"\u003e\n \u003cp\u003e1.94 (1.03~3.63)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 17px;\"\u003e\n \u003cp\u003e0.039\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 48px;\"\u003e\n \u003cp\u003eHeart disease\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 34px;\"\u003e\n \u003cp\u003e1.41 (0.81~2.47)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 17px;\"\u003e\n \u003cp\u003e0.223\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 48px;\"\u003e\n \u003cp\u003eDiabetes mellitus\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 34px;\"\u003e\n \u003cp\u003e0.81 (0.45~1.48)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 17px;\"\u003e\n \u003cp\u003e0.499\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 48px;\"\u003e\n \u003cp\u003eKidney disease\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 34px;\"\u003e\n \u003cp\u003e1.07 (0.35~3.25)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 17px;\"\u003e\n \u003cp\u003e0.904\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 48px;\"\u003e\n \u003cp\u003eRespiratory diseases\u003csup\u003e*\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 34px;\"\u003e\n \u003cp\u003e2.56 (1.25~5.27)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 17px;\"\u003e\n \u003cp\u003e0.011\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 48px;\"\u003e\n \u003cp\u003eHistory of stroke\u003csup\u003e*\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 34px;\"\u003e\n \u003cp\u003e1.95 (1.08~3.5)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 17px;\"\u003e\n \u003cp\u003e0.026\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 48px;\"\u003e\n \u003cp\u003eMental disease\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 34px;\"\u003e\n \u003cp\u003e6.62 (0.68~64.69)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 17px;\"\u003e\n \u003cp\u003e0.104\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 48px;\"\u003e\n \u003cp\u003eCCI\u003csup\u003e**\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 34px;\"\u003e\n \u003cp\u003e1.27 (1.13~1.43)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 17px;\"\u003e\n \u003cp\u003e\u0026lt;0.001\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 48px;\"\u003e\n \u003cp\u003eMNA scale\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 34px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 17px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 48px;\"\u003e\n \u003cp\u003eAt risk vs. normal nutrition\u003csup\u003e*\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 34px;\"\u003e\n \u003cp\u003e2.42 (1.1~5.32)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 17px;\"\u003e\n \u003cp\u003e0.028\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 48px;\"\u003e\n \u003cp\u003eMalnourished vs. normal nutrition\u003csup\u003e**\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 34px;\"\u003e\n \u003cp\u003e12.68 (4.09~39.37)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 17px;\"\u003e\n \u003cp\u003e\u0026lt;0.001\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 48px;\"\u003e\n \u003cp\u003eFrailty\u003csup\u003e**\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 34px;\"\u003e\n \u003cp\u003e6.1 (3.28~11.34)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 17px;\"\u003e\n \u003cp\u003e\u0026lt;0.001\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 48px;\"\u003e\n \u003cp\u003eType of fracture\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 34px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 17px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 48px;\"\u003e\n \u003cp\u003eIntertrochanteric vs. Femoral neck\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 34px;\"\u003e\n \u003cp\u003e1.53 (0.88~2.67)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 17px;\"\u003e\n \u003cp\u003e0.135\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 48px;\"\u003e\n \u003cp\u003eSubtrochanteric vs. Femoral neck\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 34px;\"\u003e\n \u003cp\u003e0.89 (0.09~8.8)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 17px;\"\u003e\n \u003cp\u003e0.917\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 48px;\"\u003e\n \u003cp\u003eSide right vs. left\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 34px;\"\u003e\n \u003cp\u003e0.92 (0.53~1.6)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 17px;\"\u003e\n \u003cp\u003e0.779\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 48px;\"\u003e\n \u003cp\u003eMultiple fractures\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 34px;\"\u003e\n \u003cp\u003e1.02 (0.45~2.28)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 17px;\"\u003e\n \u003cp\u003e0.967\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 48px;\"\u003e\n \u003cp\u003eContralateral hip fracture\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 34px;\"\u003e\n \u003cp\u003e1.54 (0.63~3.78)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 17px;\"\u003e\n \u003cp\u003e0.346\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 48px;\"\u003e\n \u003cp\u003eInternal fixation vs.\u0026nbsp;Arthroplasty\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 34px;\"\u003e\n \u003cp\u003e1.31 (0.76~2.27)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 17px;\"\u003e\n \u003cp\u003e0.337\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 48px;\"\u003e\n \u003cp\u003eSpinal anesthesia vs. General anesthesia\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 34px;\"\u003e\n \u003cp\u003e0.78 (0.44~1.41)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 17px;\"\u003e\n \u003cp\u003e0.420\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 48px;\"\u003e\n \u003cp\u003eTotal albumin\u003csup\u003e*\u003c/sup\u003e, g/L\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 34px;\"\u003e\n \u003cp\u003e0.92 (0.87~0.97)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 17px;\"\u003e\n \u003cp\u003e0.002\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 48px;\"\u003e\n \u003cp\u003eAlbumin\u003csup\u003e**\u003c/sup\u003e, g/L\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 34px;\"\u003e\n \u003cp\u003e0.86 (0.8~0.93)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 17px;\"\u003e\n \u003cp\u003e\u0026lt;0.001\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 48px;\"\u003e\n \u003cp\u003eAbsolute lymphocyte count, \u0026times;10⁹/L\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 34px;\"\u003e\n \u003cp\u003e0.81 (0.47~1.39)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 17px;\"\u003e\n \u003cp\u003e0.436\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 48px;\"\u003e\n \u003cp\u003ePNI\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 34px;\"\u003e\n \u003cp\u003e0.86 (0.8~0.93)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 17px;\"\u003e\n \u003cp\u003e\u0026lt;0.001\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 48px;\"\u003e\n \u003cp\u003ePreoperative waiting time\u0026gt; 90 hours\u003csup\u003e**\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 34px;\"\u003e\n \u003cp\u003e3.57 (1.98~6.43)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 17px;\"\u003e\n \u003cp\u003e\u0026lt;0.001\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 48px;\"\u003e\n \u003cp\u003eASA classification\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 34px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 17px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 48px;\"\u003e\n \u003cp\u003eClass III vs. Class II\u003csup\u003e*\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 34px;\"\u003e\n \u003cp\u003e11.53 (1.53~87.19)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 17px;\"\u003e\n \u003cp\u003e0.018\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 48px;\"\u003e\n \u003cp\u003eClass IV vs. Class II\u003csup\u003e**\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 34px;\"\u003e\n \u003cp\u003e32 (3.62~282.7)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 17px;\"\u003e\n \u003cp\u003e0.002\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 48px;\"\u003e\n \u003cp\u003eOperation time, hours\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 34px;\"\u003e\n \u003cp\u003e0.79 (0.54~1.16)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 17px;\"\u003e\n \u003cp\u003e0.235\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 48px;\"\u003e\n \u003cp\u003eEstimated blood loss, mL\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 34px;\"\u003e\n \u003cp\u003e1 (0.99~1)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 17px;\"\u003e\n \u003cp\u003e0.194\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 48px;\"\u003e\n \u003cp\u003ePostoperative complications\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 34px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 17px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 48px;\"\u003e\n \u003cp\u003eVenous Thromboembolism\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 34px;\"\u003e\n \u003cp\u003e1.07 (0.6~1.9)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 17px;\"\u003e\n \u003cp\u003e0.819\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 48px;\"\u003e\n \u003cp\u003eUrinary tract infections\u003csup\u003e**\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 34px;\"\u003e\n \u003cp\u003e3.52 (1.95~6.35)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 17px;\"\u003e\n \u003cp\u003e\u0026lt;0.001\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n\u003c/table\u003e\n\u003cp\u003e\u003cstrong\u003eContinued Table 2\u003c/strong\u003e\u003c/p\u003e\n\u003ctable border=\"1\" cellspacing=\"0\" cellpadding=\"0\" width=\"100%\"\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 48px;\"\u003e\n \u003cp\u003ePulmonary infection\u003csup\u003e*\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 34px;\"\u003e\n \u003cp\u003e5 (1.93~12.98)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 17px;\"\u003e\n \u003cp\u003e0.001\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 48px;\"\u003e\n \u003cp\u003eMyocardial infarction\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 34px;\"\u003e\n \u003cp\u003e8.94 (0.98~81.44)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 17px;\"\u003e\n \u003cp\u003e0.052\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 48px;\"\u003e\n \u003cp\u003eStroke\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 34px;\"\u003e\n \u003cp\u003e2.69 (0.79~9.11)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 17px;\"\u003e\n \u003cp\u003e0.112\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 48px;\"\u003e\n \u003cp\u003eGastrointestinal bleeding\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 34px;\"\u003e\n \u003cp\u003e2.15 (0.13~34.79)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 17px;\"\u003e\n \u003cp\u003e0.591\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 48px;\"\u003e\n \u003cp\u003eHb on Day 1 post-operation, g/L\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 34px;\"\u003e\n \u003cp\u003e0.98 (0.96~1)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 17px;\"\u003e\n \u003cp\u003e0.082\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n\u003c/table\u003e\n\u003cp\u003e\u003cstrong\u003eAbbreviations\u003c/strong\u003e\u003cstrong\u003e：\u003c/strong\u003e\u003cstrong\u003ePOD, postoperative delirium; BMI, Body mass index;\u0026nbsp;\u003c/strong\u003eCCI: Charlson comorbidity index; MNA scale, Mini nutritional assessment scale, \u0026quot;Nutritional status was assessed using the Mini Nutritional Assessment (MNA). Participants were classified into three groups based on MNA scores: malnourished (\u0026lt;17), at risk of malnutrition (17\u0026ndash;23.5), and normal nutritional status (\u0026ge;24).\u0026quot;; PNI, Prognostic Nutritional Index; ASA, American society of anesthesiologists; ICU, intensive care unit.\u003c/p\u003e\n\u003cp\u003e*P‑value\u0026lt;0.05 is statistically significant, **P‑value\u0026lt;0.001 is highly significant.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eTable 3\u003c/strong\u003e Logistic regression analysis relating to outcome POD\u003c/p\u003e\n\u003ctable border=\"1\" cellspacing=\"0\" cellpadding=\"0\" class=\"fr-table-selection-hover\"\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 198px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"2\" style=\"width: 180px;\"\u003e\n \u003cp\u003eUnadjusted\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"2\" style=\"width: 176px;\"\u003e\n \u003cp\u003eAdjusted\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 198px;\"\u003e\n \u003cp\u003eVariable\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 123px;\"\u003e\n \u003cp\u003eOR (95% CI)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 57px;\"\u003e\n \u003cp\u003e\u003cem\u003eP value\u003c/em\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 113px;\"\u003e\n \u003cp\u003eOR (95% CI)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 62px;\"\u003e\n \u003cp\u003e\u003cem\u003eP value\u003c/em\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 198px;\"\u003e\n \u003cp\u003e(Intercept)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 123px;\"\u003e\n \u003cp\u003e0.26 (0.17~0.40)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 57px;\"\u003e\n \u003cp\u003e\u0026lt;0.001\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 113px;\"\u003e\n \u003cp\u003e0.55 (0.01~53.92)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 62px;\"\u003e\n \u003cp\u003e0.797\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 198px;\"\u003e\n \u003cp\u003eAge \u0026gt;82 years\u003csup\u003e*\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 123px;\"\u003e\n \u003cp\u003e3.34 (1.89~5.89)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 57px;\"\u003e\n \u003cp\u003e\u0026lt;0.001\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 113px;\"\u003e\n \u003cp\u003e2.25 (1.13~4.45)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 62px;\"\u003e\n \u003cp\u003e0.020\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 198px;\"\u003e\n \u003cp\u003eHypertension\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 123px;\"\u003e\n \u003cp\u003e1.94 (1.03~3.63)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 57px;\"\u003e\n \u003cp\u003e0.039\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 113px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 62px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 198px;\"\u003e\n \u003cp\u003eRespiratory diseases\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 123px;\"\u003e\n \u003cp\u003e2.56 (1.25~5.27)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 57px;\"\u003e\n \u003cp\u003e0.011\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 113px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 62px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 198px;\"\u003e\n \u003cp\u003eHistory of stroke\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 123px;\"\u003e\n \u003cp\u003e1.95 (1.08~3.50)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 57px;\"\u003e\n \u003cp\u003e0.026\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 113px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 62px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 198px;\"\u003e\n \u003cp\u003eMNA scale\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 123px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 57px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 113px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 62px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 198px;\"\u003e\n \u003cp\u003eAt risk vs. normal nutrition\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 123px;\"\u003e\n \u003cp\u003e2.42 (1.10~5.32)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 57px;\"\u003e\n \u003cp\u003e0.028\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 113px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 62px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 198px;\"\u003e\n \u003cp\u003eMalnourished vs. normal nutrition\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 123px;\"\u003e\n \u003cp\u003e12.68 (4.09~39.37)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 57px;\"\u003e\n \u003cp\u003e\u0026lt;0.001\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 113px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 62px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 198px;\"\u003e\n \u003cp\u003eCCI\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 123px;\"\u003e\n \u003cp\u003e1.27 (1.13~1.43)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 57px;\"\u003e\n \u003cp\u003e\u0026lt;0.001\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 113px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 62px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 198px;\"\u003e\n \u003cp\u003ePreoperative waiting\u003c/p\u003e\n \u003cp\u003e\u0026nbsp; \u0026nbsp;time \u0026gt; 90 hours\u003csup\u003e**\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 123px;\"\u003e\n \u003cp\u003e3.57 (1.98~6.43)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 57px;\"\u003e\n \u003cp\u003e\u0026lt;0.001\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 113px;\"\u003e\n \u003cp\u003e2.65 (1.3~5.37)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 62px;\"\u003e\n \u003cp\u003e0.007\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 198px;\"\u003e\n \u003cp\u003eFrailty\u003csup\u003e*\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 123px;\"\u003e\n \u003cp\u003e6.10 (3.28~11.34)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 57px;\"\u003e\n \u003cp\u003e\u0026lt;0.001\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 113px;\"\u003e\n \u003cp\u003e2.40 (1.08~5.32)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 62px;\"\u003e\n \u003cp\u003e0.031\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 198px;\"\u003e\n \u003cp\u003eASA classification\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 123px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 57px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 113px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 62px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 198px;\"\u003e\n \u003cp\u003eClass III vs. Class II\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 123px;\"\u003e\n \u003cp\u003e11.53 (1.53~87.19)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 57px;\"\u003e\n \u003cp\u003e0.018\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 113px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 62px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 198px;\"\u003e\n \u003cp\u003eClass IV vs. Class II\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 123px;\"\u003e\n \u003cp\u003e32.00 (3.62~282.70)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 57px;\"\u003e\n \u003cp\u003e0.002\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 113px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 62px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n\u003c/table\u003e\n\u003cp\u003e\u003cstrong\u003eContinued Table 3\u003c/strong\u003e\u003c/p\u003e\n\u003ctable border=\"1\" cellspacing=\"0\" cellpadding=\"0\"\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 198px;\"\u003e\n \u003cp\u003eUrinary tract infections\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 123px;\"\u003e\n \u003cp\u003e3.52 (1.95~6.35)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 57px;\"\u003e\n \u003cp\u003e\u0026lt;0.001\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 113px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 62px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 198px;\"\u003e\n \u003cp\u003ePulmonary infection\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 123px;\"\u003e\n \u003cp\u003e5.00 (1.93~12.98)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 57px;\"\u003e\n \u003cp\u003e0.001\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 113px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 62px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 198px;\"\u003e\n \u003cp\u003ePNI\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 123px;\"\u003e\n \u003cp\u003e0.86 (0.80~0.93)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 57px;\"\u003e\n \u003cp\u003e\u0026lt;0.001\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 113px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 62px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 198px;\"\u003e\n \u003cp\u003eTotal albumin, g/L\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 123px;\"\u003e\n \u003cp\u003e0.92 (0.87~0.97)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 57px;\"\u003e\n \u003cp\u003e0.002\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 113px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 62px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n\u003c/table\u003e\n\u003cp\u003e\u003cstrong\u003eAbbreviations\u003c/strong\u003e\u003cstrong\u003e：\u003c/strong\u003e\u003cstrong\u003ePOD, postoperative delirium;\u0026nbsp;\u003c/strong\u003eCCI: Charlson comorbidity index; MNA scale, Mini nutritional assessment scale, \u0026quot;Nutritional status was assessed using the Mini Nutritional Assessment (MNA). Participants were classified into three groups based on MNA scores: malnourished (\u0026lt;17), at risk of malnutrition (17\u0026ndash;23.5), and normal nutritional status (\u0026ge;24).\u0026quot;; PNI, Prognostic Nutritional Index.\u003c/p\u003e\n\u003cp\u003e*P‑value\u0026lt;0.05 is statistically significant, **P‑value\u0026lt;0.001 is highly significant.\u003c/p\u003e"},{"header":"Discussion","content":"\u003cp\u003eThis study elucidates three modifiable determinants of POD in geriatric hip fracture patients, with frailty (adjusted OR\u0026thinsp;=\u0026thinsp;2.40), advanced age (\u0026gt;\u0026thinsp;82 years; adjusted OR\u0026thinsp;=\u0026thinsp;2.25), and prolonged preoperative waiting time (\u0026gt;\u0026thinsp;90 hours; adjusted OR\u0026thinsp;=\u0026thinsp;2.65) emerging as independent predictors. The robust association between frailty and POD aligns with mechanistic evidence implicating diminished physiological reserve\u0026mdash;manifested through impaired mitochondrial function and dysregulated neuroendocrine stress responses\u0026mdash;in delirium pathogenesis[\u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e16\u003c/span\u003e, \u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e17\u003c/span\u003e]. Crucially, our temporal quantification of surgical delays advances existing literature: each incremental hour beyond the 90-hour threshold conferred a 165% escalation in delirium risk (OR\u0026thinsp;=\u0026thinsp;2.65), underscoring the critical necessity for healthcare systems to implement expedited surgical protocols for this vulnerable demographic. These findings redefine geriatric perioperative care priorities, positioning biological resilience metrics and time-sensitive intervention as dual pillars for delirium prevention strategies.\u003c/p\u003e \u003cp\u003eOur study conclusively demonstrates that preoperative frailty is a critical predictor of POD in elderly patients with hip fractures, aligning with prior findings[\u003cspan additionalcitationids=\"CR19\" citationid=\"CR18\" class=\"CitationRef\"\u003e18\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR20\" class=\"CitationRef\"\u003e20\u003c/span\u003e]. In older hospitalized patients, preoperative frailty correlates with postoperative complications, including POD. Leung et al. reported an independent association between frailty and POD in non-cardiac surgery cohorts[\u003cspan citationid=\"CR21\" class=\"CitationRef\"\u003e21\u003c/span\u003e]. A recent meta-analysis of 15 cohorts (n\u0026thinsp;=\u0026thinsp;3,250) revealed a 27.1% prevalence of preoperative frailty and a 15.8% incidence of POD, with frailty significantly elevating POD risk (OR\u0026thinsp;=\u0026thinsp;3.23)[\u003cspan citationid=\"CR22\" class=\"CitationRef\"\u003e22\u003c/span\u003e]. These results resonate with studies by Shooka Esmaeeli et al.[\u003cspan citationid=\"CR23\" class=\"CitationRef\"\u003e23\u003c/span\u003e] (geriatric trauma cohort, n\u0026thinsp;=\u0026thinsp;556, OR\u0026thinsp;=\u0026thinsp;1.33) and Chen et al.[\u003cspan citationid=\"CR24\" class=\"CitationRef\"\u003e24\u003c/span\u003e] (total hip arthroplasty cohort, n\u0026thinsp;=\u0026thinsp;383, OR\u0026thinsp;=\u0026thinsp;3.31), both identifying frailty as an independent predictor of POD. Our adjusted OR of 2.65 corroborates these findings.\u003c/p\u003e \u003cp\u003eThis alignment underscores the mechanistic pathways through which frailty exacerbates neurocognitive risks. Frailty, defined by diminished physiological reserve and impaired stress response, predisposes patients to POD through interconnected mechanisms. Chronic inflammation, often termed \"inflammatory aging,\" marked by elevated pro-inflammatory cytokines such as interleukin-6 and tumor necrosis factor-α, disrupts the integrity of the blood-brain barrier[\u003cspan citationid=\"CR25\" class=\"CitationRef\"\u003e25\u003c/span\u003e, \u003cspan citationid=\"CR26\" class=\"CitationRef\"\u003e26\u003c/span\u003e]. This inflammatory burden is compounded by mitochondrial dysfunction[\u003cspan citationid=\"CR27\" class=\"CitationRef\"\u003e27\u003c/span\u003e], which generates oxidative stress, triggers neuronal apoptosis, and impairs synaptic plasticity. Additionally, hypothalamic-pituitary-adrenal (HPA) axis dysregulation disrupts cortisol rhythm, contributing to cognitive fluctuations[\u003cspan citationid=\"CR28\" class=\"CitationRef\"\u003e28\u003c/span\u003e]. These insights highlight the potential of targeted frailty interventions, such as anti-inflammatory therapies or NAD\u0026thinsp;+\u0026thinsp;supplementation, as innovative strategies to mitigate the risk of POD[\u003cspan citationid=\"CR29\" class=\"CitationRef\"\u003e29\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eOur multivariate analysis substantiates advanced age (\u0026gt;\u0026thinsp;82 years) as an independent predictor of POD (adjusted OR\u0026thinsp;=\u0026thinsp;2.25), a finding that extends beyond chronological age to reflect multidimensional biological aging processes. This association likely arises from synergistic interactions between neurovascular senescence and diminished cholinergic resilience. Notably, from current researches, it can be inferred that aging-induced reductions in α7 nicotinic acetylcholine receptor density within the prefrontal cortex notably impair the integrity of attentional networks critical for delirium resistance [\u003cspan additionalcitationids=\"CR31\" citationid=\"CR30\" class=\"CitationRef\"\u003e30\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR32\" class=\"CitationRef\"\u003e32\u003c/span\u003e]. The exponential risk escalation observed in octogenarians (POD incidence: 63.2% vs. 34.0% in non-POD cohort) delineates a critical biological threshold where cumulative oxidative stress intersects with blood-brain barrier permeability alterations to exacerbate neuroinflammatory cascades[\u003cspan citationid=\"CR33\" class=\"CitationRef\"\u003e33\u003c/span\u003e, \u003cspan citationid=\"CR34\" class=\"CitationRef\"\u003e34\u003c/span\u003e]. Mechanistically, age-related neurodegenerative remodeling[\u003cspan citationid=\"CR35\" class=\"CitationRef\"\u003e35\u003c/span\u003e]\u0026mdash;characterized by cerebral hypoperfusion, neuronal attrition, and white matter hyperintensities\u0026mdash;compromises cognitive reserve capacity, rendering geriatric patients disproportionately vulnerable to surgical stressors. These findings align with epidemiological evidence demonstrating that 53% of individuals aged 80\u0026ndash;84 years harbor two or more comorbidities\u0026mdash;particularly chronic inflammatory conditions\u0026mdash;that potentiate cerebral microvascular dysfunction and neurocognitive instability[\u003cspan citationid=\"CR36\" class=\"CitationRef\"\u003e36\u003c/span\u003e]. Critically, our results corroborate the paradigm of gerosurgical vulnerability, emphasizing the imperative for age-stratified perioperative protocols to mitigate POD risk in hip fracture populations through targeted modulation of neuroinflammation and metabolic homeostasis.\u003c/p\u003e \u003cp\u003eNumerous studies have established that an extended preoperative waiting time represents a crucial risk factor for POD[\u003cspan citationid=\"CR37\" class=\"CitationRef\"\u003e37\u003c/span\u003e, \u003cspan citationid=\"CR38\" class=\"CitationRef\"\u003e38\u003c/span\u003e]. Specifically, in hip fracture surgeries, a waiting time exceeding 36 hours significantly increases the risk of postoperative complications such as pneumonia, myocardial infarction, and heart failure within 30 days after the surgery[\u003cspan citationid=\"CR39\" class=\"CitationRef\"\u003e39\u003c/span\u003e]. Moreover, when the preoperative waiting time surpasses 90 hours, the risk of POD escalates by 2.65-fold. This finding aligns remarkably well with the clinical consensus on the urgency of hip fracture surgeries. The underlying association likely emerges through the concerted action of multiple intricate mechanisms. Firstly, surgical delay precipitates persistent pain and a stress response[\u003cspan citationid=\"CR38\" class=\"CitationRef\"\u003e38\u003c/span\u003e], thereby activating the HPA axis and leading to excessive glucocorticoid (GC) release[\u003cspan citationid=\"CR40\" class=\"CitationRef\"\u003e40\u003c/span\u003e, \u003cspan citationid=\"CR41\" class=\"CitationRef\"\u003e41\u003c/span\u003e]. Prolonged exposure to high GC levels can induce hippocampal neuronal damage via glucocorticoid receptor dysfunction and impaired neuroplasticity[\u003cspan citationid=\"CR41\" class=\"CitationRef\"\u003e41\u003c/span\u003e]. Animal studies have demonstrated that GCs can promote the generation of neuronal reactive oxygen species (ROS) and enhance Caspase-3 activity through the activation of the NLRP-1 inflammasome, exacerbating hippocampal neuronal injury[\u003cspan citationid=\"CR42\" class=\"CitationRef\"\u003e42\u003c/span\u003e]. Additionally, GCs impede hippocampus-dependent learning and memory functions by inhibiting the expression of brain-derived neurotrophic factor (BDNF) and reducing synaptic protein levels[\u003cspan additionalcitationids=\"CR44\" citationid=\"CR43\" class=\"CitationRef\"\u003e43\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR45\" class=\"CitationRef\"\u003e45\u003c/span\u003e]. Intriguingly, research has shown that accelerated muscle catabolism caused by prolonged bed rest (\u0026gt;\u0026thinsp;72 hours) releases myogenic pro-inflammatory factors (such as myostatin), intensifying systemic inflammation[\u003cspan citationid=\"CR46\" class=\"CitationRef\"\u003e46\u003c/span\u003e]. In hip fracture patients, elevated postoperative serum levels of IL-6 and IL-8 are positively correlated with the risk of delirium[\u003cspan citationid=\"CR47\" class=\"CitationRef\"\u003e47\u003c/span\u003e, \u003cspan citationid=\"CR48\" class=\"CitationRef\"\u003e48\u003c/span\u003e]. Furthermore, dysbiosis of the gut microbiota leads to tryptophan metabolism disorders and increased blood-brain barrier permeability[\u003cspan citationid=\"CR49\" class=\"CitationRef\"\u003e49\u003c/span\u003e], enabling the accumulation of neurotoxic metabolites (such as quinolinic acid) in the brain. As an NMDA receptor agonist, quinolinic acid can induce glutamate excitotoxicity and neuronal apoptosis[\u003cspan citationid=\"CR50\" class=\"CitationRef\"\u003e50\u003c/span\u003e].​\u003c/p\u003e \u003cp\u003eCurrently, there is a growing body of evidence advocating for the reduction of preoperative waiting time to mitigate the risk of POD [\u003cspan citationid=\"CR38\" class=\"CitationRef\"\u003e38\u003c/span\u003e, \u003cspan citationid=\"CR51\" class=\"CitationRef\"\u003e51\u003c/span\u003e, \u003cspan citationid=\"CR52\" class=\"CitationRef\"\u003e52\u003c/span\u003e]. Prolonged preoperative waiting time means to delayed surgery, and even a 24-hour delay has been identified as a predictor of minor medical postoperative complications, including delirium. In this study, delays exceeding 48 hours were found to be associated with severe medical complications[\u003cspan citationid=\"CR53\" class=\"CitationRef\"\u003e53\u003c/span\u003e]. Studies have demonstrated that fast-tracking and early surgery can reduce the incidence of postoperative complications such as delirium [\u003cspan citationid=\"CR54\" class=\"CitationRef\"\u003e54\u003c/span\u003e]. However, inconsistencies exist in the literature regarding the role of preoperative waiting time as a risk factor. While some studies have found a positive association between prolonged waiting time and increased POD risk[\u003cspan citationid=\"CR51\" class=\"CitationRef\"\u003e51\u003c/span\u003e, \u003cspan citationid=\"CR55\" class=\"CitationRef\"\u003e55\u003c/span\u003e], others have not established a significant link[\u003cspan citationid=\"CR56\" class=\"CitationRef\"\u003e56\u003c/span\u003e, \u003cspan citationid=\"CR57\" class=\"CitationRef\"\u003e57\u003c/span\u003e]. For instance, Lee et al. reported that preoperative waiting times exceeding 36 hours from emergency admission only affected the incidence of POD in patients with pre-existing dementia[\u003cspan citationid=\"CR58\" class=\"CitationRef\"\u003e58\u003c/span\u003e]. Similarly, Pioli et al. observed that preoperative waiting time influenced POD rates only in patients with mild-to-moderate preoperative cognitive impairment, whereas no significant effect was noted in cognitively healthy hip fracture patients[\u003cspan citationid=\"CR59\" class=\"CitationRef\"\u003e59\u003c/span\u003e]. Despite these findings, the optimal timing of surgery remains a subject of debate. Supporters of immediate surgery argue that it reduces the duration of bed rest for patients, thereby lowering the risk of postoperative complications[\u003cspan citationid=\"CR60\" class=\"CitationRef\"\u003e60\u003c/span\u003e]. In contrast, those advocating for delayed surgery maintain that postponing the procedure allows for sufficient time to optimize patient health, which can lead to a reduction in the likelihood of complications during the perioperative period[\u003cspan citationid=\"CR61\" class=\"CitationRef\"\u003e61\u003c/span\u003e]. For patients with inevitable surgical delays, preoperative prehabilitation (such as nutritional support and anti-inflammatory interventions) may partially counteract the adverse effects of waiting time by improving metabolic status and microbiota homeostasis.\u003c/p\u003e \u003cp\u003eNeither the type of anesthesia (CSEA versus GA) nor the surgical procedure (joint replacement versus internal fixation) demonstrated a significant correlation with the incidence of POD, a finding that aligns with recent meta-analyses[\u003cspan citationid=\"CR62\" class=\"CitationRef\"\u003e62\u003c/span\u003e]. Although combined spinal-epidural anesthesia was predominantly used in both cohorts (67.1% in the POD group vs. 72.2% in the non-POD group), this distribution likely reflects institutional protocols rather than therapeutic benefits. These results imply that the susceptibility to delirium in elderly fracture patients may be more influenced by intrinsic physiological frailty than by differences in surgical procedures, underscoring the need for a shift toward comprehensive geriatric assessment programs. Our analysis further indicates that hip fracture type, preoperative medication, and fracture side are not significantly associated with POD. These findings suggest that these factors may not be critical determinants of delirium risk following hip fracture surgery.\u003c/p\u003e \u003cp\u003eThe strong correlation between infectious complications (particularly urinary and pulmonary infections) and POD (OR\u0026thinsp;=\u0026thinsp;3.52\u0026ndash;5.00) corroborates neuroinflammatory models of delirium. However, their exclusion from the multivariate model implies these infections may manifest as intermediary events along the delirium pathway rather than primary etiological drivers. This observation reinforces the need for mechanistic studies disentangling bidirectional relationships between systemic inflammation and neural dysfunction in POD.\u003c/p\u003e \u003cp\u003eThis study reports a significantly higher incidence of myocardial infarction in POD patients (5.3% vs. 0.6%), potentially driven by delirium-associated sympathetic hyperactivation and systemic inflammatory responses[\u003cspan citationid=\"CR63\" class=\"CitationRef\"\u003e63\u003c/span\u003e]. Animal experiments demonstrate that delirium-like states can induce mitochondrial uncoupling of oxidative phosphorylation in the myocardium, leading to acute cardiac dysfunction[\u003cspan citationid=\"CR27\" class=\"CitationRef\"\u003e27\u003c/span\u003e]. Additionally, our findings showed that POD patients had a prolonged intensive care unit (ICU) length of stay, consistent with previous studies[\u003cspan citationid=\"CR64\" class=\"CitationRef\"\u003e64\u003c/span\u003e], likely due to the need for longer mechanical ventilation, more complex care, and higher resource utilization. Compared to Hernandez et al.'s study on post-anesthesia care unit delirium, the higher POD rate (31.9% vs. 16.4%) in our cohort may reflect greater physiological frailty in hip fracture patients[\u003cspan citationid=\"CR65\" class=\"CitationRef\"\u003e65\u003c/span\u003e]. While both studies confirmed the risks of delayed surgery, our results highlighted frailty (rather than ASA classification) as an independent predictor, indicating that traditional anesthesia risk assessment tools like the ASA may underestimate the biological age differences in the elderly.\u003c/p\u003e \u003cp\u003eThis study has several limitations. First, the single-center design and the absence of inflammatory biomarker assessment (e.g., IL-6, CRP) could restrict the generalizability of the findings. Second, residual confounding from unmeasured variables, such as undiagnosed neuropathies, may still persist despite meticulous control of known confounders. Third, the observational nature of the study precludes definitive conclusions about the causal relationship between preoperative waiting time and the onset of delirium. Future research should incorporate multicenter studies that integrate single-cell transcriptomics and metabolomics to better define the molecular subtypes of POD. Additionally, randomized controlled trials evaluating interventions targeting frailty are essential to confirm their effectiveness in reducing the risk of POD.\u003c/p\u003e"},{"header":"Conclusion","content":"\u003cp\u003eIn summary, this study reveals a high incidence of POD in elderly hip fracture patients and identifies advanced age, frailty, and prolonged preoperative waiting time as independent risk factors. These findings highlight the importance of optimizing preoperative assessment, accelerating surgical procedures, and implementing multidisciplinary interventions. While the study offers key insights, its single-center design and lack of inflammatory biomarker assessment may limit generalizability. Future research should involve multicenter studies, integrate omics technologies, and evaluate interventions targeting frailty to further clarify the molecular mechanisms and clinical management strategies for POD.\u003c/p\u003e"},{"header":"Declarations","content":"\u003ch2\u003eDeclarations\u003c/h2\u003e \u003cp\u003e\u003cb\u003eAuthor contributions\u003c/b\u003e Yuzhi Wei, Haotian Wu and Huan Zhang conceptualized and designed the study, coordinated and supervised data collection, drafted the initial manuscript, and approved the final manuscript as submitted. Chunyu Feng, Ziheng Qi and Yujie Wang carried out the initial analyses, reviewed and revised the manuscript, and approved the final manuscript as submitted. Haotian Wu, Yuzhi Wei, and Huan Zhang designed the data collection, critically reviewed the manuscript, and approved the final manuscript as submitted. All authors approved the final manuscript as submitted and agree to be accountable for all aspects of the work.\u003c/p\u003e \u003cp\u003e \u003cstrong\u003eEthical approval\u003c/strong\u003e \u003cp\u003e This study was approved by the Institutional Review Board of Beijing Tsinghua Changgung Hospital, School of Clinical Medicine, Tsinghua University (Approval No. 21277-0-01). The protocol was prospectively registered at ClinicalTrials.gov (NCT05246254).\u003c/p\u003e \u003c/p\u003e \u003cp\u003e \u003cstrong\u003eConflicts of Interest\u003c/strong\u003e \u003cp\u003eThe authors declare that there is no conflict of interest.\u003c/p\u003e \u003c/p\u003e\u003ch2\u003eFunding Sources\u003c/h2\u003e \u003cp\u003eThis research was financially supported by the Beijing Municipal Administration of Hospitals Incubating Program [Approval No. PX2022037].\u003c/p\u003e \u003cp\u003eData availability The corresponding author can provide the raw data of this study upon reasonable request.\u003c/p\u003e\u003ch2\u003eAuthor Contribution\u003c/h2\u003e\u003cp\u003eYuzhi Wei, Haotian Wu and Huan Zhang conceptualized and designed the study, coordinated and supervised data collection, drafted the initial manuscript, and approved the final manuscript as submitted. Chunyu Feng, Ziheng Qi and Yujie Wang carried out the initial analyses, reviewed and revised the manuscript, and approved the final manuscript as submitted. Haotian Wu, Yuzhi Wei, and Huan Zhang designed the data collection, critically reviewed the manuscript, and approved the final manuscript as submitted. All authors approved the final manuscript as submitted and agree to be accountable for all aspects of the work.\u003c/p\u003e\u003ch2\u003eAcknowledgements\u003c/h2\u003e \u003cp\u003eWe would like to thank all the patients who participated in this study.\u003c/p\u003e\u003ch2\u003eData Availability\u003c/h2\u003e\u003cp\u003eThe corresponding author can provide the raw data of this study upon reasonable request.\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\n\u003cli\u003eSwarbrick CJ, Partridge JSL (2022) Evidence-based strategies to reduce the incidence of postoperative delirium: a narrative review. \u003cem\u003eAnaesthesia\u003c/em\u003e, 77 Suppl 1:92-101.https://doi.org/10.1111/anae.15607\u003c/li\u003e\n\u003cli\u003eFlikweert ER, Wendt KW, Diercks RL, Izaks GJ, Landsheer D, Stevens M\u003cem\u003e, et al\u003c/em\u003e (2018) Complications after hip fracture surgery: are they preventable? 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Indian J Orthop, 45:27-32. https://doi.org/10.4103/0019-5413.73660\u003c/li\u003e\n\u003cli\u003eGitajn IL, Werth P, Fernandes E, Sprague S, O\u0026apos;Hara NN, Bzovsky S\u003cem\u003e, et al\u003c/em\u003e (2022) Association of Patient-Level and Hospital-Level Factors With Timely Fracture Care by Race. JAMA Netw Open, 5:e2244357. https://doi.org/10.1001/jamanetworkopen.2022.44357\u003c/li\u003e\n\u003cli\u003eQi YM, Li YJ, Zou JH, Qiu XD, Sun J, Rui YF (2022) Risk factors for postoperative delirium in geriatric patients with hip fracture: A systematic review and meta-analysis. Front Aging Neurosci, 14:960364. https://doi.org/10.3389/fnagi.2022.960364\u003c/li\u003e\n\u003cli\u003eWu F, Liu Z, Zhou L, Ye D, Zhu Y, Huang K\u003cem\u003e, et al\u003c/em\u003e (2022) Systemic immune responses after ischemic stroke: From the center to the periphery. Front Immunol, 13:911661. https://doi.org/10.3389/fimmu.2022.911661\u003c/li\u003e\n\u003cli\u003eLu S, Jiang Y, Meng F, Xie X, Wang D, Su Y (2024) Risk factors for postoperative delirium in patients with Stanford type A aortic dissection: a systematic review and meta-analysis. J Cardiothorac Surg, 19:16. https://doi.org/10.1186/s13019-024-02485-5\u003c/li\u003e\n\u003cli\u003eHernandez BA, Lindroth H, Rowley P, Boncyk C, Raz A, Gaskell A\u003cem\u003e, et al\u003c/em\u003e (2017) Post-anaesthesia care unit delirium: incidence, risk factors and associated adverse outcomes. Br J Anaesth, 119:288-290. https://doi.org/10.1093/bja/aex197\u003c/li\u003e\n\u003c/ol\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":true,"highlight":"","institution":"","isAcceptedByJournal":false,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true},"keywords":"Postoperative delirium, Hip fracture, Frailty, Preoperative waiting time, Aging","lastPublishedDoi":"10.21203/rs.3.rs-6635767/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-6635767/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003ch2\u003eBackground\u003c/h2\u003e \u003cp\u003ePostoperative Delirium (POD) is a relatively common acute neurocognitive complication in elderly patients with hip fractures. However, its exact incidence rate and risk factors have not been fully elucidated.\u003c/p\u003e\u003ch2\u003eMethods\u003c/h2\u003e \u003cp\u003eThis prospective study enrolled 238 elderly patients undergoing surgical repair for hip fractures between January 2022 and September 2024. Using univariate and multivariate logistic regression analyses, we identified factors associated with POD and evaluated its correlation with intensive care unit (ICU) length of stay, total hospitalization duration, and postoperative complications.\u003c/p\u003e\u003ch2\u003eResults\u003c/h2\u003e \u003cp\u003eThe incidence of POD was 31.9% (76/238). Multivariate analysis revealed that advanced age (\u0026gt;\u0026thinsp;82 years; adjusted OR\u0026thinsp;=\u0026thinsp;2.25, 95% CI: 1.13\u0026ndash;4.45, P\u0026thinsp;=\u0026thinsp;0.020), prolonged preoperative waiting time (\u0026gt;\u0026thinsp;90 hours; OR\u0026thinsp;=\u0026thinsp;2.65, 95% CI: 1.30\u0026ndash;5.37, P\u0026thinsp;=\u0026thinsp;0.007), and frailty (OR\u0026thinsp;=\u0026thinsp;2.40, 95% CI: 1.08\u0026ndash;5.32, P\u0026thinsp;=\u0026thinsp;0.031) were independently associated with POD. Patients with POD exhibited significantly prolonged ICU stays (median 17.8 days vs. 0 days, P\u0026thinsp;\u0026lt;\u0026thinsp;0.001) and total hospitalization (13 days vs. 10 days, P\u0026thinsp;\u0026lt;\u0026thinsp;0.001), along with higher rates of postoperative infections (urinary tract infections: 47.4% vs. 20.4%, P\u0026thinsp;\u0026lt;\u0026thinsp;0.001).\u003c/p\u003e\u003ch2\u003eConclusion\u003c/h2\u003e \u003cp\u003ePOD is highly prevalent in elderly hip fracture patients and strongly linked to frailty, prolonged preoperative waiting time, and advanced age. These factors substantially increase healthcare burden, highlighting the need for optimized preoperative assessment, reduced waiting times, and multidisciplinary interventions to mitigate POD risk.\u003c/p\u003e","manuscriptTitle":"Risk Factors for Postoperative Delirium in Elderly Hip Fracture Patients: A Prospective Observational Analysis","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2025-06-03 07:04:00","doi":"10.21203/rs.3.rs-6635767/v1","editorialEvents":[{"type":"communityComments","content":0}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"91405f01-6f16-4449-adaf-11d45827df05","owner":[],"postedDate":"June 3rd, 2025","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"posted","subjectAreas":[],"tags":[],"updatedAt":"2025-09-29T20:23:12+00:00","versionOfRecord":[],"versionCreatedAt":"2025-06-03 07:04:00","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-6635767","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-6635767","identity":"rs-6635767","version":["v1"]},"buildId":"8U1c8b4HqxoKbykW_rLl7","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}