Non-biologic disease-modifying antirheumatic drugs (DMARDs) improve pain in inflammatory arthritis (IA): a systematic literature review of randomized controlled trials

Evidence supports early use of non-biologic DMARDs to prevent irreversible damage in inflammatory arthritides, including rheumatoid arthritis (RA), psoriatic arthritis (PsA), and possibly ankylosing spondylitis (AS). However, there is a paucity of data exploring their effects on pain as a primary outcome in these conditions. This systematic literature review investigated the effect of non-biologic DMARDs on pain levels in IA and examined whether disease duration impacted efficacy. We searched Medline, Embase, Cochrane Central, and Cochrane Database of Systematic Reviews, abstracts from the 2008 to 2010 American College of Rheumatology annual congresses, and citation lists of retrieved publications. Only randomized, double-blind controlled trials were analyzed. Quality was assessed with the Risk of Bias tool. Descriptive statistics were used in meta-analysis. 9,860 articles were identified, with 33 eligible for inclusion: 8 in AS, 6 in PsA, 9 in early RA (ERA), and 10 in established RA. In ERA and established RA, all studies of DMARDs (monotherapy and combination therapies) consistently revealed statistically significant reductions in pain except three oral gold studies. In AS, sulfasalazine studies showed significant pain reduction, whereas use of other DMARDs did not. In PsA, 5 of 6 studies reported VAS-pain improvement. From the studies included, we were unable to assess the influence of disease duration on pain outcomes in these rheumatic conditions. DMARDs improve pain in early and established RA. Sulfasalazine may improve pain in AS and PsA. Further study is needed to assess the relationship between disease duration and DMARD efficacy in reducing pain in these conditions.