Abstract: Objective  To identify the risk factors associated with contralateral hip fracture and to develop a nomogram-based clinical prediction model. Methods  A retrospective study was conducted including 1 871 elderly patients hospitalized for hip fracture at the bone center of a tertiary hospital in Beijing, China, between January 2016 and December 2022. Patients who developed a contralateral hip fracture within 3 years after surgery (n=76) were assigned to the case group, while those without contralateral hip fracture (n=1 695) as the control group. Demographic characteristics, comorbidities, and laboratory findings were collected. Least absolute shrinkage and selection operator (LASSO) regression followed by multivariate Logistic regression analyses were used to identify the risk factors for contralateral hip fracture, and a nomogram-based prediction model was developed by using R software. The model was evaluated with the receiver operating characteristic (ROC) curve, the Hosmer-Lemeshow goodness-of-fit test, and decision curve analysis (DCA). Results  Overall, 9.4% (176/1 871) of patients experienced a contralateral hip fracture within 3 years after surgery. Multivariate Logistic regression analysis identified age, history of diabetes mellitus, history of osteoporotic fractures at other sites, peripheral vascular disease, visual impairment, and platelet count as independent risk factors for contralateral hip fracture in older patients (P < 0.05). The ROC analysis indicated that the nomogram yield an area under the curve (AUC) of 0.729 (95% CI: 0.685-0.773). The Hosmer-Lemeshow test indicated good agreement between predicted and observed risks, and DCA confirmed that the model provided a net clinical benefit. Conclusion  Age, history of diabetes mellitus, history of osteoporotic fractures at other sites, peripheral vascular disease, visual impairment, and platelet count are independent risk factors for contralateral hip fracture in older patients. The nomogram incorporating these variables exhibits moderate predictive performance and may serve as a useful tool to assist clinicians in perioperative management and treatment decision-making following initial hip fracture surgery.

Key words: hip fractures, contralateral hip fracture, aged, risk factors, risk assessment, nomograms