Frailty and prolonged preoperative waiting time as independent predictors of postoperative delirium in older hip fracture patients

Postoperative Delirium (POD) is a relatively common acute neurocognitive complication in elderly patients with hip fractures. However, its incidence and independent risk factors remain incompletely defined. This analysis utilized prospectively collected data from 238 consecutive patients with hip fractures aged ≥ 60 years. Univariate analyses were first used to assess potential risk factors for POD. Variables showing significant associations underwent collinearity testing, and those with high variance inflation factors (VIF > 5.0) were excluded. To ensure model stability per the Events Per Variable (EPV) principle and to focus on clinically meaningful predictors, a final set of 7 variables was entered into a multivariate logistic regression model to identify independent predictors of POD. The analysis included 238 patients with an average age of 79.0 years, of whom 73.1% were women. The overall incidence of POD was 31.9%. Those who developed POD were significantly older (82.5 vs. 77.3 years) and a higher proportion were female (77.6% vs. 71.0%). Multivariate analysis identified four independent predictors of POD: frailty (OR = 2.62, 95% CI 1.22-5.62, P = 0.014), a preoperative waiting time exceeding 90 h (OR = 2.59, 95% CI 1.31-5.15, P = 0.007), postoperative infection (OR = 2.41, 95% CI 1.21-4.82, P = 0.013), and advanced age over 82 years (OR = 2.44, 95% CI 1.26-4.73, P = 0.008). Patients with POD experienced longer ICU stays (median 17.8 days vs. 0 days, P < 0.001) and longer total hospitalization (13 days vs. 10 days, P < 0.001). Frailty, prolonged preoperative waiting time, postoperative infection, and advanced age were identified as independent predictors of POD in older hip fracture patients. These findings may help improve understanding of delirium risk in this population and suggest areas for further investigation. Further studies are warranted to explore causal mechanisms and to evaluate whether perioperative interventions aimed at reducing waiting time, assessing frailty, or preventing infections might mitigate the risk of POD.