Hip Fracture Geriatric (HIP-G) Index: Predicting 12-Month Mortality in Older Adults With Hip Fracture

Abstract

Objectives: Hip fractures in older adults are associated with high mortality, disability, and functional decline. Although tools like the Multidimensional Prognostic Index (MPI) are validated for risk stratification, their use is limited in acute care due to time constraints and the need for comprehensive interviews. The aim of this study was to define a faster, clinically applicable tool for mortality prediction.

Design: Prospective observational study.

Setting and participants: The study included patients aged ≥65 years who were hospitalized for a fragility hip fracture within our Fracture Liaison Service program between March 2023 and March 2024.

Methods: Clinical, laboratory, and multidimensional geriatric assessment data were collected at admission. One-year mortality was the primary outcome. Predictors of mortality were identified using multivariable Cox regression, and a prognostic score-HIP fracture Geriatric Index (HIP-G Index)-was developed. Its performance was compared with the MPI and Charlson Comorbidity Index (CCI) using receiver operating characteristic analysis and the Hosmer-Lemeshow test.

Results: We included 592 patients with a mean age of 84.4 years; 71.5% were female. At 12 months, 129 patients (21.8%) had died. The HIP-G Index (based on creatinine, cognitive, nutritional domains, and comorbidities) showed superior predictive accuracy [area under the curve (AUC) = 0.799] vs MPI (AUC = 0.734) and CCI (AUC = 0.678, P < .001). The model was well-calibrated (Hosmer-Lemeshow P = .24). A simplified categorical score (0-4 points) stratified patients into low-, moderate-, and high-risk groups, with corresponding hazard ratios of 7.2 and 16.9 for mortality (P < .001). Kaplan-Meier analysis confirmed significant survival differences between risk groups.

Conclusions and implications: The HIP-G Index is a valid, user-friendly tool for predicting 1-year mortality in older adults with hip fracture and may support decision making in time-constrained clinical settings.

Keywords: Hip fractures; geriatric; mortality; multidimensional evaluation; older adults.