Predicting physical activity and general health perception among patients with rheumatoid arthritis.

OBJECTIVE: To describe changes over one year in physical activity, body functions, and disease activity in patients with rheumatoid arthritis (RA) and to identify predictors for physical activity and general health perception.
METHODS: One hundred two patients with RA were recruited for the study (median age 57 yrs, range 19-84; median disease duration 15 mo, range 4-78; 76% women). Self-reported data on physical activity and health locus of control, tests of lower extremity function, grip force, joint range of motion, balance, and measures of disease activity, including pain, general health perception, Health Assessment Questionnaire (HAQ), and Disease Activity Score (DAS28), were collected on 2 occasions, one year apart. Each variable was dichotomized to fit logistic regression models, performed to identify which variables predicted physical activity and general health perception over one year.
RESULTS: Physical activity was stable, while lower extremity function, grip force, and range of motion improved and DAS28 decreased significantly over one year. A high physical activity level at baseline was the only predictor of high physical activity (odds ratio 3.85, 95% confidence interval 1.67-9.09) one year later. Low pain (OR 8.47, 95% CI 2.97-24.39), high physical activity (OR 3.72, 95% CI 1.39-10.10), and good lower extremity function (OR 2.94, 95% CI 1.04-8.33) were identified as predictors of good general health perception.
CONCLUSION: While pain is a well known predictor of general health perception, to our knowledge, this is the first study to identify predictive factors related to physical activity and lower extremity function as important for perceived health among patients with RA.