The risk factors and predictive nomogram for postoperative hypoalbuminemia in elderly patients undergoing hip arthroplasty

Background Postoperative hypoalbuminemia is a common nutritional-related complication in elderly patients undergoing hip replacement surgery, which is a common nutritional-related disorder that reflects nutritional imbalance during the perioperative period and is closely associated with adverse clinical outcomes, such as an increased risk of postoperative infection and prolonged hospital stay. Objective This study aimed to identify the independent risk factors for postoperative hypoalbuminemia in elderly patients undergoing hip arthroplasty, and to develop a nomogram-based risk prediction model for perioperative clinical application. The ultimate goal was to facilitate early identification of high-risk patients and guide targeted interventions to reduce postoperative complication rates. Methods A retrospective cohort study was conducted, enrolling 308 elderly patients who underwent hip arthroplasty from January 2015 to September 2024. Univariate analysis was first performed to screen potential risk factors. Variables with a p value <0.05 in univariate analysis were then included in multivariate stepwise logistic regression to identify independent predictors. A nomogram was constructed to visualize the prediction model. Model performance was assessed using three metrics: discrimination (via area under the receiver operating characteristic [ROC] curve, AUC), calibration (via Hosmer-Lemeshow test and Brier score), and clinical utility (via decision curve analysis [DCA]). Results Postoperative hypoalbuminemia occurred in 170 of 308 patients (55.19%). Multivariate regression identified five independent risk factors: total fluid intake, preoperative serum total protein (TP), hydroxybutyrate dehydrogenase (HBDH), international normalized ratio (INR), and plasma D-dimer. Model calibration was excellent: the Hosmer-Lemeshow test yielded a χ 2 value of 6.997 ( p = 0.537); the ROC curve yielded an AUC of 0.752 (95% CI: 0.699–0.805). The calibration curve showed good consistency between the predicted and actual probabilities. Decision curve analysis (DCA) showed that using the nomogram had a high net benefit. Conclusion Total fluid intake, preoperative TP, HBDH, INR and D-dimer level are five independent risk factors for postoperative hypoalbuminemia in elderly patients undergoing hip arthroplasty. The nomogram-based prediction model developed in this study exhibits good calibration, good discrimination and favorable clinical utility, making it a practical tool for guiding targeted clinical nutritional interventions, thereby optimizing patients’ nutritional status and improving their clinical outcomes.