Abstract
OBJECTIVE: Health-related utility measures overall health status and quality of life and is commonly incorporated into cost-effectiveness analyses. This study investigates whether attainment of federal physical activity guidelines translates into better health-related utility in adults with or at risk for knee osteoarthritis (OA). METHODS: Cross-sectional data from 1,908 adults with or at risk for knee OA participating in the accelerometer ancillary study of the Osteoarthritis Initiative were assessed. Physical activity was measured using 7 days of accelerometer monitoring and was classified as 1) meeting guidelines (≥150 bouted moderate-to-vigorous [MV] minutes per week); 2) insufficiently active (≥1 MV bout[s] per week but below guidelines); or 3) inactive (zero MV bouts per week). A Short Form 6D health-related utility score was derived from patient-reported health status. Relationship of physical activity levels to median health-related utility adjusted for socioeconomic and health factors was tested using quantile regression. RESULTS: Only 13% of participants met physical activity guidelines, and 45% were inactive. Relative to the inactive group, median health-related utility scores were significantly greater for the meeting guidelines group (0.063; 95% confidence interval [95% CI] 0.055, 0.071) and the insufficiently active group (0.059; 95% CI 0.054, 0.064). These differences showed a statistically significant linear trend and strong cross-sectional relationship with physical activity level even after adjusting for socioeconomic and health factors. CONCLUSION: We found a significant positive relationship between physical activity level and health-related utility. Interventions that encourage adults, including persons with knee OA, to increase physical activity even if recommended levels are not attained may improve their quality of life.