Temporal effect of depressive symptoms on the longitudinal evolution of rheumatoid arthritis disease activity.

OBJECTIVE: Depression is common in the rheumatoid arthritis (RA) population, yet little is known of its effect on the course of disease activity. The aim of our study was to determine if prevalent and incident depressive symptoms influenced longitudinal changes in RA disease activity.
METHODS: RA patients with and without depressive symptoms were identified using single-item questions from an existing registry sample. Mixed-effects models were used to examine changes in disease activity over 2 years in those with and without prevalent and incident depressive symptoms. Outcome variables included composite disease activity, joint counts, global assessments, pain, function, and acute-phase reactants. Model-based outcome estimations at the index dates and corresponding 1- and 2-year changes were calculated.
RESULTS: Rates of disease activity change were significantly different in patients with a lifetime prevalence of symptomology, but not incident depressive symptoms, when compared to controls. Prior symptoms were associated with slower rates of disease activity decline, evidenced by the estimated 1-year Clinical Disease Activity Index changes: -3.0 (-3.3, -2.6) and -4.0 (-4.3, -3.6) in patients with and without lifetime prevalence, respectively. Analogous results were obtained for most of the other disease activity outcomes; although, there was no temporal effect of prevalent symptoms of depression on swollen joints and acute-phase reactants.
CONCLUSION: Depressive symptoms temporally influence the evolution of RA disease activity, and the magnitude is dependent on the time of symptomatic onset. However, the effect is limited to patient-reported pain, global assessment, and function, as well as physician-reported global assessment and tender joints.