Contribution of ischemic stroke to hip fracture risk and the influence of gender difference

Objectives: To clarify the contribution of stroke to the risk of hip fracture (HF) and the influence of gender difference on HF, and to estimate the incidence rate of poststroke HF. Design: A prospective, probability-sampling, 10-year, population-based cohort study. Setting: A National Health Insurance Research Database consisting of 200,432 randomly selected enrollees. Participants: Subjects with acute ischemic stroke (N=1951; mean age ± SD, 65.6±9.8y; 56.5% men) were identified. For each stroke subject, 2 age- and gender-matched controls were recruited. Control subjects did not have any brain disease. Those subjects younger than 45 years were excluded. Interventions: Not applicable. Main Outcome Measures: The incidence rate and the adjusted hazard ratio of sustaining an HF were estimated. The cumulative HF-free probability was plotted. Results: Stroke subjects had a higher incidence rate of HF than their controls (women: 11.3 vs 4.4/1000 person-years, P<.001; men: 5.6 vs 2.9/1000 person-years, P<.001). The risk of HF was higher among stroke subjects, yielding an adjusted hazard ratio (95% confidence interval) of 2.33 (1.623.34) for women and 1.73 (1.122.68) for men. Compared with men with stroke, women with stroke had an adjusted hazard ratio of 1.83 (1.182.85). Stroke subjects had a lower cumulative HF-free probability throughout the 10-year duration than did the control subjects (women, P<.001; men, P=.005). Half of the poststroke HFs occurred within 2.5 years of the onset of stroke. Conclusions: Ischemic stroke is a risk factor for HF, which is at work over and beyond age and gender. Being a woman with stroke increases this fracture risk. An active program for fracture prevention might prove effective for stroke subjects, and this may be especially true for women.