Characterization of Hip Fractures Among Adults With Schizophrenia in Ontario, Canada

Abstract

Importance: Evidence suggests that individuals with schizophrenia are at an increased risk of hip fractures; however, the sex-specific burden of hip fractures among adults with schizophrenia has not been quantified and compared with the general population. Objective: To describe sociodemographic and clinical characteristics of patients with hip fracture and schizophrenia and to quantify their sex-specific annual hip fracture rates relative to those without schizophrenia. Design, Setting, and Participants: This repeated population-based, cross-sectional study leveraged multiple individually linked health administrative databases for patients in Ontario, Canada. We included patients aged 40 to 105 years with hip fracture-related hospitalization between April 1, 2009, and March 31, 2019. Statistical analysis was performed between November 2021 and February 2023. Exposure: Schizophrenia diagnosis, ascertained using a validated algorithm. Main Outcomes and Measures: The main outcome was sex-specific age-standardized annual hip fracture rate per 10000 individuals and annual percent change in age-standardized rates. Rates were direct adjusted to the 2011 Ontario population, and joinpoint regression analysis was performed to evaluate annual percent change. Results: We identified 117431 hip fracture records; of these, there were 109908 index events. Among the 109908 patients with hip fracture, 4251 had schizophrenia and 105657 did not. Their median age was 83 years (IQR, 75-89 years), and 34 500 (31.4%) were men. Patients with hip fracture and schizophrenia were younger at the index event compared with those without schizophrenia. Men had a median age of 73 vs 81 years (IQR, 62-83 vs 71-87 years; standardized difference, 0.46), and women had a median age of 80 vs 84 years (IQR, 71-87 vs 77-89 years; standardized difference, 0.32). A higher proportion of patients with vs without schizophrenia had frailty (53.7% vs 34.2%; standardized difference, 0.40) and previous fragility fractures (23.5% vs 19.1%; standardized difference, 0.11). The overall age-standardized rate per 10000 individuals with vs without schizophrenia was 37.5 (95% CI, 36.4 to 38.6) vs 16.0 (95% CI, 15.9 to 16.1). Age-standardized rates were 3-fold higher in men with vs without schizophrenia (31.0 [95% CI, 29.5 to 32.6] vs 10.1 [95% CI, 10.0 to 10.2]) and more than 2-fold higher in women with vs without schizophrenia (43.4 [95% CI, 41.9 to 44.9] vs 21.4 [95% CI, 21.3 to 21.6]). Overall, joinpoint regression analysis identified a steady annual decrease of 0.7% (95% CI, -1.1% to -0.3%) in age-standardized rates for both study groups. Conclusions and Relevance: The findings of this cross-sectional study suggest that individuals with schizophrenia experience an earlier age of onset and considerably higher rate of hip fractures compared with the general population, with implications for targeted fracture prevention and optimization of clinical bone health management over the course of their psychiatric illness.