Background The disease activity score assessing 28 joints (DAS28) is the gold standard for measuring disease activity in rheumatoid arthritis (RA) clinical trials. A proportion of the total DAS-28 reflects subjective report of disease activity, viz., tender joint count (TJC) and VAS general health (GH) to the DAS28. This proportion, DAS28-P, is calculated as follows : (0.56 * √28TJC + 0.014 * VAS GH)/(0.28 * √28SJC + 0.56 * √28TJC + 0.7 * ln(ESR) + 0.014 * VAS GH). A high DAS-28-P may indicate a high contribution of non-inflammatory factors, which may be associated with non-response to pharmacological treatment. Previously we could not confirm this hypothesis in a cohort of RA patients treated with their first biological .
Objectives To investigate whether high DAS28-P at baseline is associated with poor EULAR response to conventional DMARDs at 3 months in early DMARD-naïve RA patients. We validated these results using the 28TJC:28SJC ratio as alternative measure of non-inflammatory components of disease activity .
Methods We analysed data of the second Computer-Assisted Management in Early Rheumatoid Arthritis trial (CAMERA-II) in which 236 early DMARD naïve RA patients were randomized to start therapy with either methotrexate (MTX) + 10mg prednisone or MTX + placebo . We performed ordinal regression analysis to assess the association between baseline DAS28-P (predictor variable) and EULAR response at 3 months (outcome variable, classed as no, moderate or good response), adjusted for treatment arm. We repeated this analysis using as predictor variable baseline 28TJC:28SJC ratio (after log-transformation), adjusted for treatment arm.
Results Neither baseline DAS28-P nor the ratio of tender and swollen joints was associated with EULAR response at 3 months:
Conclusions These results show that a high contribution of tender joint count and VAS GH to the DAS28 is not associated with poor clinical response to treatment in early DMARD-naïve RA-patients. This is in line with our previous study on this topic in RA patients receiving their first biological DMARD treatment and indicates not to withhold (stepping up) immunosuppressive treatment from RA patients with a high contribution of tender joint count and VAS GH to the DAS28.
McWilliams DF, et al. Predictors of change in bodily pain in early rheumatoid arthritis: An inception cohort study. Arthritis Care Res 2012;64:1505–13.
Jurgens M, et al. Contribution of the subjective components of the Disease Activity Score to the response to Biological Treatment in Rheumatoid Arthritis. Arthritis Care Res 2014;:Epub ahead of print.
Pollard LC, et al. Fibromyalgic rheumatoid arthritis and disease assessment. Rheumatology (Oxford) 2010;49:924–8.
Bakker MF, et al. Low-dose prednisone inclusion in a methotrexate-based, tight control strategy for early rheumatoid arthritis: a randomized trial. Ann Intern Med 2012;156:329–39.
Disclosure of Interest None declared