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 (1.62-3.34) for women and 1.73 (1.12-2.68) for men. Compared with men with stroke, women with stroke had an adjusted hazard ratio of 1.83 (1.18-2.85). 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.