Three-Year Sustained Remission in Early RA: Predictors and Structural Outcomes. Analysis of Longitudinal Observational Data in Two Multicentre UK Inception Cohorts over 25 Years

Background Achieving sustained remission in Rheumatoid Arthritis (RA) is more important than achieving point remission, albeit more challenging, and likely to have greater impact on long-term outcomes of disease such as orthopaedic surgery (OS). Objectives To examine baseline predictors and OS, a surrogate marker of joint destruction, in RA patients with sustained disease activity score (DAS) remission over the first 3 years (3yrRem). Methods Using a single mode of data collection, 1465 DMARD naïve patients were recruited into the Early RA Study (ERAS, 9 centres, 1986-1998) & 1236 patients into the Early RA Network (ERAN, 23 centres, 2002-2012). Standard clinical, radiological & laboratory measures were performed yearly for a maximum 25 & 10yrs (median 10 & 3yrs respectively). 3yrRem was defined as persisting DAS of ≤3.2 at 6 months (following treatment-onset), 1, 2 & 3 yrs. In-patient hospital episodes were recorded yearly, including OS. Major OS (M-OS) included large total joint replacements (mainly hips/knees) & intermediate OS (I-OS) included hand/foot surgery. Source data of all OS included clinical datasets (patient reports & medical records from 1986) & national data from Hospital Episode Statistics & the National Joint Registry. Length of follow up was based on the National Death Registry. Treatment regimens followed guidelines of the era, mainly conventional DMARDs, +/− steroids & latterly biologics. Results Out of 2701 patients, 154 (5.7%) were in 3yrRem following onset of treatment. In Logistic regression analysis, baseline DAS was the single clinical/laboratory predictor (OR 0.60, p