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

Abstract

Background: Patients with established rheumatoid arthritis (RA) frequently miss Boolean remission solely because of the patient global assessment of disease activity (PGA) exceeding the cut-off of 1. Here, we investigated the frequency and the limiting variables to disease remission in patients with early RA treated with conventional synthetic disease modifying anti-rheumatic drugs according to a treat-to-target strategy, depending on the autoantibody status. Methods: Data were retrieved from 535 early RA patients (<12 months of symptoms), treatment-naïve at inclusion, with an observation period of 6 to 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 4 core items of Boolean remission exceeding the cut-off of 1 with the remaining 3 all ≤1. Reasons for missing Boolean remission and predictors of near-remission subcategories were analysed in relation to baseline disease variables. Results: After 6 and 12 months from treatment start, 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-misses (56.2% and 57.6% at 6 and 12 months, respectively), and PGA >1 accounted for approximatively 35% of the cases. None of the variables of disease activity neither patient reported outcomes at baseline could discriminate SJC28 from PGA near-misses. Rather, autoantibody-positivity independently predicted the risk of missing remission because of SJC28 >1 with an adjusted OR [95% CI] of 3.62 [1.89-6.93] at 6 months and 2.36 [1.25-4.47] at 12 months, whilst autoantibody-negativity was an independent predictor of PGA near-miss (adjusted OR [95% CI] 2.71 [1.31-5.64] at 6 months and 6.50 [2.47-17.12] at 12 months). Conclusions: In patients with 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 the PGA more frequently impairs the achievement of remission in autoantibody-negative patients. These findings indicate that efforts to target full-remission in early RA may require different treatment strategies according to the autoantibody profile.