UC Davis

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.