The effect of anti-inflammatory treatment on depressive symptoms in spondyloarthritis: does the type of drug matter?

OBJECTIVE: To investigate the effect of pharmacological treatment of SpA on depressive symptoms and explore whether this effect differs between drug classes. METHODS: Data from the observational Assessment of SpondyloArthritis international Society Health Index Validation Study were used. Patients were assessed at baseline and after initiation of NSAIDs/conventional synthetic DMARDs (csDMARDs)/TNF inhibitors (TNFis). Depressive symptoms were assessed with the Hospital Anxiety and Depression Scale depression subscale [HADS-D; 0-21 (best-worst)]. Covariables included demographics and disease characteristics, including disease activity [Ankylosing Spondylitis Disease Activity Score (ASDAS)/BASDAI]. The change in HADS-D from baseline was compared between treatments (NSAIDs/csDMARDs/TNFis) with analysis of variance and multivariable regression analysis. RESULTS: A total of 304 patients were included; 102/45/157 initiated NSAIDs/csDMARDs/TNFis and 260 (85%) / 44 (15%) had axial/peripheral SpA. At baseline, the mean HADS-D was 6.9 (s.d. 4.2); 126 (42%) were possibly depressed (HADS-D ≥8) and 66 (22%) were probably depressed (HADS-D ≥11). At follow-up, depressive symptoms significantly improved in all treatment groups. In multivariable regression without disease activity measures, initiating TNFis compared with NSAIDs was associated with greater improvement in depressive symptoms [ß = -1.27 (95% CI -2.23, -0.32)] and lower odds of possible depression at follow-up [odds ratio 0.47 (95% CI 0.23, 0.94)]. This association was attenuated after additional adjustment for disease activity (ASDAS/BASDAI) but not CRP. csDMARDs did not differ from NSAIDs regarding their effect on HADS-D. Between-drug class results were confirmed in axial SpA (axSpA), although less clear in peripheral SpA. CONCLUSION: Treatment of active SpA also improves depressive symptoms. Especially in axSpA, TNFis have a greater effect than NSAIDs, which is mainly explained by a stronger effect on disease activity. We found no evidence for a direct link between CRP-mediated inflammation and depressive symptoms in SpA.