Identifying patients with rheumatoid arthritis with moderate disease activity at risk of significant radiographic progression despite methotrexate treatment

OBJECTIVES: To determine the baseline factors predictive of significant radiographic progression (SRP) in patients with moderately active rheumatoid arthritis (RA) despite receiving methotrexate (MTX). METHODS: Patients from the MTX arm of the Trial of Etanercept and Methotrexate with Radiographic Patient Outcomes (TEMPO) trial with sustained moderate RA (defined as ≥3.2 mean disease activity score in 28 joints ≤5.1 during the last 6 months of the first year) were analysed for SRP (mTSS >3.0 overall) after 2 and 3 years. Baseline predictors for SRP were identified by univariate and multivariate analyses. All variables shown to be significantly associated with SRP were categorised based on clinically relevant cut-offs and tertiles and were included in a matrix risk model. RESULTS: 228 patients were assigned MTX treatment, 210 patients were in the radiographic intention-to-treat population, and 96 of these had sustained moderate RA. SRP occurred in 25 (26%) and 33 (34%) patients after 2 and 3 years of MTX treatment, respectively. Univariate and multivariate analyses found that C reactive protein (CRP) and rheumatoid factor (RF) positivity at baseline were predictive of SRP after 2 and 3 years (p<0.05 for all). The matrix risk model showed that RF positivity and CRP levels >40 mg/L at baseline were significantly associated with SRP after 2 (p<0.05 for both; R(2)=0.24) and 3 years (p<0.05 for both; R(2)=0.22). The baseline erosion score was not found to be predictive of SRP. CONCLUSIONS: Patients with sustained moderate RA despite receiving MTX treatment are at risk of SRP, with both RF positivity and high CRP levels shown to be predictive of this.