The prospective association between psychological distress and disease activity in rheumatoid arthritis: a multilevel regression analysis.

BACKGROUND: Cross-sectional associations suggest a mutual impact of disease activity and psychological distress in rheumatoid arthritis (RA), but a prospective association has not been established. OBJECTIVE: To examine concurrent and prospective associations between psychological distress and disease activity. METHODS: Patients with RA (N=545, disease duration </=1 year, age 18-83 years, 69% female, 64% rheumatoid factor (RF) positive) were monitored for 5 years. The Thompson joint score and erythrocyte sedimentation rate were assessed every 6 months. Depressed mood and anxiety were measured every 12 months. Multilevel regression analysis was used. RF positivity, age and female sex were included as covariates. RESULTS: Concurrent levels of psychological distress and disease activity were positively associated (p</=0.04). Prospectively, depressed mood was associated with disease activity levels 6 months later (p</=0.04). The Thompson joint score was associated with psychological distress levels 6 months later (p</=0.03) and also with an increase in depressed mood over the subsequent 6 months (p=0.02). No other significant prospective associations were found (p>/=0.07). CONCLUSIONS: Psychological distress and disease activity are positively associated when measured at the same time as well as when measured 6 months apart. While some support was found for the idea that a higher level of disease activity is a risk factor for an increase in psychological distress, the results do not support the notion that psychological distress is a risk factor for future exacerbation of disease activity