To prospectively analyze patient questionnaire scores concerning functional disability as well as formal education level as potential predictors of premature mortality over 10 years in 1416 patients with rheumatoid arthritis (RA) from 15 private practice rheumatology settings in 11 diverse cities in the United States.
At baseline in 1985 and periodically over 10 years, patients completed mailed self-report multidimensional health assessment questionnaires (MDHAQ) that included functional disability scores, formal education level, and other demographic and clinical data. Vital status was determined 10 years after baseline. Potential predictors of 10 year mortality were analyzed using descriptive statistics and Cox proportional hazards models.
Vital status was accounted for in 1378 patients, 97.3% of the cohort. The standard mortality ratio was 1.6, similar to most reported series of patients with RA, as 401 patients died versus 251 expected over 10 years. Evidence of "dose-response" relations was seen for age, formal education level, functional disability scores, and helplessness scores as predictors of mortality. In Cox proportional hazards models, age, sex, formal education level, functional disability, and helplessness scores remained significant independent predictors of 10 year mortality.
Functional disability and low formal education level are significant predictors of premature mortality in people with RA under care in US private practice settings, as in most reported cohorts of patients with RA. This study shows that it is possible to account for more than 95% of patients over 10 years using mailed questionnaires to monitor patient status.