Abstract
PURPOSE: Depressive symptoms are common in rheumatoid arthritis (RA) and may affect disease activity and treatment outcomes. The objective of this study was to determine if prevalent depressive symptoms modify biologic treatment response through their effect on RA disease activity. METHODS: RA patients with depressive symptoms, initiating biologic treatment, were identified from a US RA registry sample. Patients with depression were compared with control subjects (ie, those patients with no reports of depressive symptoms at, or before, initiating therapy) in terms of clinical disease activity index (CDAI) remission and low disease activity (LDA), and the changes in the component measures that comprise this scale at 6 and 12 months of follow-up. Inverse probability weighting was used to account for differences in baseline disease severity, concomitant treatment characteristics, and other possible confounders. Logistic and linear regression models estimated differences in response rates and changes in component disease activity measures. FINDINGS: Depressive symptoms were associated with a decreased likelihood of CDAI remission at 6 months (odds ratio, 0.43 [95% CI, 0.19-0.96]) but not at 12 months (odds ratio, 0.83 [95% CI, 0.43-1.60]), and there was no effect on CDAI LDA. Adjusted core component measurement changes showed smaller decreases in global assessment ratings in patients with depressive symptoms; these associations were not statistically significant. IMPLICATIONS: Poorer treatment outcomes among RA patients with depressive symptoms may be a result of higher baseline disease severity. Adjusted estimates indicated symptoms of depression only affected remission at 6 months' follow-up through patient and physician global assessments. Thus, any impact of depressive symptoms during biologic treatment might not be due to a definitive impact on joint swelling and tenderness.