Identifying Risk Factors for Postoperative Delirium Following Hip Fracture Surgery in Older Adults: A Retrospective Cohort Study

Background Postoperative delirium (POD) is a common and serious complication after hip fracture surgery in older adults. Early identification of modifiable risk factors is essential for prevention. Methods This retrospective cohort study included 481 patients aged ≥ 65 years who underwent hip fracture surgery from January 2020 to September 2025. POD was identified using a validated two-step chart review combining automated keyword triggering with independent dual-expert adjudication. Multivariable logistic regression with backward stepwise selection was used to identify independent predictors. Results POD occurred in 79 of 481 patients (16.4%). Independent risk factors were male sex (adjusted OR 2.96, 95% CI 1.69–5.18; P < 0.001), older age (adjusted OR 1.15 per year, 95% CI 1.10–1.21; P < 0.001), and preoperative pulmonary infection (adjusted OR 2.05, 95% CI 1.05–3.99; P = 0.035). Hypertension was independently protective (adjusted OR 0.42, 95% CI 0.22–0.78; P = 0.006). The final model showed good discrimination (AUC 0.797, 95% CI 0.736–0.858) and calibration (Hosmer–Lemeshow P = 0.289). Conclusions Male sex, advanced age, and preoperative pulmonary infection are modifiable or identifiable risk factors for POD after hip fracture surgery in Chinese older adults, whereas hypertension appears protective, possibly due to long-term antihypertensive therapy. Routine preoperative screening and treatment of pulmonary infection are warranted in this population.