Development of functional impairment and disability in rheumatoid arthritis patients followed for 20 years - relation to disease activity, joint damage and comorbidity.
Objectives. To study the course of impairment measured by signals of functional impairment (SOFI) and disability measured by health assessment questionnaire (HAQ) over 20 years in rheumatoid arthritis (RA) patients followed from diagnosis. To explore the contribution of disease activity, joint damage and comorbidity to variation of SOFI and HAQ over time. Methods. RA patients diagnosed 1985-1989 w