Reductions in radiographic progression in early RA over 25-years: changing contribution from RF in 2 multi-centre UK inception cohorts

Objectives: To assess 5-year progression of erosions and Joint Space Narrowing (JSN), and their associations with RF status in two large, multi-centre early-RA cohorts spanning 25-years. Methods: Radiographic joint damage was recorded using the Sharp/van der Heijde (SvdH) method in the Early RA Study (ERAS) 1986-2001, and the Early RA Network (ERAN) 2002-2013. Mixed-effects negative-binomial regression estimated changes in radiographic damage over 5-years, including erosions and JSN separately. Rheumatoid Factor (RF), along with age, sex and baseline markers of disease activity were controlled for. Results: 1,216 patients from ERAS and 446 from ERAN had radiographic data. Compared to ERAS, ERAN patients had a lower mean total SvdH score at baseline (ERAN=6.2 vs. ERAS=10.5, p<0.001), and mean annual rate of change (ERAN=2.5 vs. ERAS=6.9 per year, p<0.001). 74% of ERAS and 27% of ERAN patients progressed ≥5 units. Lower scores at baseline in ERAN were largely driven by reductions in JSN (ERAS=3.9 vs. ERAN=1.2, p<0.001), along with erosions (ERAS=1.9 vs. ERAN=0.8, p<0.001). RF was associated with greater progression in each cohort, but the absolute difference in mean annual rate of change for RF positive patients was substantially higher for ERAS (RF+= 8.6 vs. RF-= 5.1, p<0.001), relative to ERAN (RF+= 2.0 vs. RF-= 1.9, p=0.855). Conclusion: Radiographic progression has significantly reduced between the two cohorts, associated with lower baseline damage and other factors, including changes in early DMARD use. The impact of RF status as a prognostic marker of clinically meaningful change in radiographic progression has markedly diminished in the context of more modern treatment. This article is protected by copyright. All rights reserved.