Overall and Relative Survival After a Second Contralateral Hip Fracture in Adults over 65 Years: A Retrospective...

Background/Objectives: The main objective of this study was to estimate 1- and 3-year overall survival and relative survival in patients aged >65 years who underwent surgery for a second contralateral hip fracture. Methods: Retrospective cohort study including patients aged ≥65 years who underwent surgery for a first or second contralateral hip fracture between June 2010 and December 2021. Overall survival (OS) was estimated from the date of surgery to death from any cause or end of follow-up. Relative survival (RS) was calculated as the ratio between observed survival and expected survival derived from general population mortality tables for Catalonia implemented in the WebSurvCa application. Results: A total of 2642 patients were included (2467 primary fractures; 175 s contralateral fractures). Patients with a second fracture were older and had worse pre-fracture functional and cognitive status. At 3 years, overall survival was 53.8% (95% CI: 51.7-55.9) after a first fracture and 43.7% (95% CI: 36.3-52.4) after a second contralateral fracture. Relative survival estimates were 70.5% (95% CI: 67.7-73.3) and 59.0% (95% CI: 49.1-70.8), respectively. Divergence between expected and relative survival became more evident at 3 years than at 1 year. Advanced age, male sex, and worse pre-fracture functional or cognitive status were associated with poorer survival in both cohorts. Conclusions: A second contralateral hip fracture may represent a clinically relevant marker of increased vulnerability and greater clinical complexity, associated with substantial excess mortality compared with general population matched by age and sex. Relative survival highlights the true prognostic burden of a primary or second fracture and supports intensive secondary prevention and tailored follow-up.