Association Between C-reactive Protein to Albumin Ratio and Mortality in Geriatric Hip Fracture Patients

zObjective: The objective of this study was to evaluate the relationship between admission C-reactive protein (CRP) to albumin ratio (CAR) and 30-day mortality in older adults undergoing surgical treatment for hip fractures.Methods: This retrospective study included patients aged 65 years who presented to the emergency department of a tertiary care hospital with a diagnosis of hip fracture and subsequently underwent surgical treatment between January 2023 and January 2025.Demographic, clinical, and laboratory data were extracted from electronic records.The CAR was determined by dividing the serum CRP level (mg/L) by the serum albumin level (g/L), based on laboratory values obtained upon hospital admission.The primary outcome was 30-day all-cause mortality.Multivariable logistic regression was used to identify independent predictors.Model discrimination was assessed using the area under the receiver operating characteristic curve (AUROC), and calibration was evaluated using the Hosmer-Lemeshow test.The optimal CAR cut-off was determined via Youden's index.Results: Among the 411 patients, 43 (10.5%)died within 30 days.Non-survivors were older, predominantly male, and had higher American Society of Anesthesiologists scores, lower serum albumin and hemoglobin levels, and higher CRP levels.Median CAR was significantly higher in deceased patients (14.8 vs. 3.5, p<0.001).In multivariate analysis, CAR remained an independent predictor of 30-day mortality [adjusted odds ratio: 2.77; 95% confidence interval (CI): 2.14-3.76].The AUROC for CAR was 0.930 (95% CI: 0.860-0.988),and the optimal cut-off value of 6.5 yielded 88.4% sensitivity and 96.2% specificity. Conclusion:CAR at admission was independently associated with short-term mortality in geriatric patients undergoing hip fracture surgery.As a readily obtainable marker reflecting systemic inflammation and nutritional status, CAR may serve as a valuable tool for early risk stratification in emergency orthopedic care.