The long-term impact of rheumatoid arthritis and comorbidity on functioning and mortality

This thesis presents the results of a longitudinal study on comorbidity, functioning and mortality in patients with rheumatoid arthritis (RA). RA is associated with emerging comorbidities resulting in substantial impacts on functioning and mortality. Limited information exists on these interrelationships. Also more information is needed to evaluate the risk of all cause- and cardiovascular (CV) mortality in patients with RA in comparison with the general population. We collected longitudinal data over a period of 11 years. We found that both somatic comorbidity and comorbid depression at baseline were associated with worse physical functioning over the entire 11-year followup period. Especially comorbid circulatory-, respiratory-, musculoskeletal conditions, cancer, and depression were associated with worse physical functioning. Respiratory conditions and depression were associated with worse mental functioning. The observed mortality among patients with RA was 54% higher than in the general population after adjustment for age, sex, and calendar year. However, mortality tended to decrease over time. Mortality was higher for circulatory, respiratory, musculoskeletal and digestive system diseases. Predictors for CV mortality were higher age, higher erythrocyte sedimentation rate, CV comorbidity and diabetes mellitus. Our results emphasize the need for paying targeted attention to both somatic comorbidity and comorbid depression in clinical practice. Raising awareness among rheumatologist about the importance of comorbidity will contribute to increasing the quality of care and improving the quality of life and chance of survival of patients with RA.