Hip Osteoarthritis and the Risk of All‐Cause and Disease‐Specific Mortality in Older Women: A Population‐Based Cohort Study

OBJECTIVE: To determine the risk of all-cause and disease-specific mortality among older women with hip osteoarthritis (OA) and to identify mediators in the causal pathway. METHODS: Data were from the Study of Osteoporotic Fractures, a US population-based cohort study of 9,704 white women age ≥65 years. The analytic sample included women with hip radiographs at baseline (n = 7,889) and year 8 (n = 5,749). Mortality was confirmed through October 2013 by death certificates and hospital discharge summaries. Radiographic hip OA (RHOA) was defined as a Croft grade of ≥2 in at least 1 hip (definite joint space narrowing or osteophytes plus 1 other radiographic feature). RESULTS: The mean ± SD followup time was 16.1 ± 6.2 years. The baseline and year 8 prevalence of RHOA were 8.0% and 11.0%, respectively. The cumulative incidence (proportion of deaths during the study period) was 67.7% for all-cause mortality, 26.3% for cardiovascular disease (CVD) mortality, 11.7% for cancer mortality, 1.9% for gastrointestinal disease mortality, and 27.8% for all other mortality causes. RHOA was associated with an increased risk of all-cause mortality (hazard ratio 1.14 [95% confidence interval 1.05-1.24]) and CVD mortality (hazard ratio 1.24 [95% confidence interval 1.09-1.41]) adjusted for age, body mass index, education, smoking, health status, diabetes, and stroke. These associations were partially explained by the mediating variable of physical function. CONCLUSION: RHOA was associated with an increased risk of all-cause and CVD mortality among older white women followed up for 16 years. Dissemination of evidence-based physical activity and self-management interventions for hip OA in community and clinical settings can improve physical function and might also contribute to lower mortality.