Factors predicting health-related quality of life in knee osteoarthritis among community-dwelling women in Japan: the Hizen-Oshima study.

Knee osteoarthritis is the most common chronic joint disorder in elderly people. However, a population-based, longitudinal study on health-related quality of life in knee osteoarthritis has not been conducted in Japan. We studied 333 women aged 50 years and older at baseline, with 8 to 9 years of follow-up. Anteroposterior weight-bearing knee radiographs were obtained at baseline and graded according to the Kellgren-Lawrence criteria. Definite osteoarthritis was defined as Kellgren-Lawrence grade 2 or higher in at least 1 joint. At baseline, all participants were asked if they had knee pain and comorbidities (heart disease, lung disease, stroke, or diabetes mellitus). Height (m), weight (kg), and chair stand time were measured. At follow-up, quality of life in knee osteoarthritis was evaluated using the Japanese Knee Osteoarthritis Measure score. Multiple linear regression analysis showed that age, knee osteoarthritis, knee pain, comorbidity, and increasing chair stand time were independently related to subsequent health-related quality of life. These findings suggest that treating knee osteoarthritis and comorbidities, managing pain, and optimizing lower extremity muscle strength may be effective targets for intervention.