Limiting factors to Boolean remission differ between autoantibody-positive and -negative patients in early rheumatoid arthritis

Background: The patient global assessment of disease activity (PGA) is the major limiting factor to Boolean remission in patients with established rheumatoid arthritis (RA). Here, we investigated the limiting variables to disease remission in patients with early RA treated with conventional synthetic disease modifying anti-rheumatic drugs, also in relation to autoantibody status. Methods: Data were retrieved from 535 early RA patients (<12 months of symptoms) with an observation period of 6-12 months upon initiation of therapy with methotrexate aimed at the achievement of low disease activity based on the 28-joints disease activity score. Near-remission was defined as any of the four core items of Boolean remission >1 with the remaining three all <= 1. Reasons for missing Boolean remission and predictors of near-remission subcategories were analyzed in relation to baseline disease variables. Results: After 6 and 12 months, near-remission was two-times more frequent than Boolean remission (25.6% and 26.9% at the two time-points). A 28-swollen joint count (SJC28) >1 was responsible for the majority of near-remission (56.2% and 57.6% at 6 and 12 months, respectively), and PGA>1 accounted for approximatively 35% of the cases. Autoantibody-positivity independently predicted the risk of missing remission because of SJC28>1 [adjusted odds ratio (OR) 95% confidence interval (CI) 2.81 (1.59-4.9) at 6 months and 1.73 (1.01-3.01) at 12 months], whilst autoantibody-negativity was an independent predictor of PGA near-remission [adjusted OR (95% CI) 2.45 (1.25-4.80) at 6 months and 5.71 (2.47-13.2) at 12 months]. Conclusion: In early RA, Boolean remission is more frequently missed because of persistent swollen joints. However, barriers to full-remission vary in relation to the autoantibody status. Autoantibody-positive patients more commonly experience residual swollen joints, whilst PGA more frequently impairs remission in autoantibody-negative patients. Efforts to target full-remission in early RA may thus require different strategies according to autoantibody profile.