Rheumatoid Arthritis Magnetic Resonance Imaging Score Predicts Therapy Response: Results of the German ArthroMark Cohort.

Objective: Markers for treatment response in rheumatoid arthritis (RA) are lacking. The aim of the study was to assess the performance of the RA magnetic resonance imaging (MRI) scoring system (RAMRIS) in combination with serum biomarkers to predict response to methotrexate (MTX) treatment in therapy-naive patients with early RA by using high-field MRI.

Methods: Twenty-eight patients with RA were prospectively assessed with baseline 3-T MRI of the clinical dominant hand, 3 and 6 months after MTX. The patients met the 2010 American College of Rheumatology/European League Against Rheumatism (EULAR) criteria [average age 56.8 yrs (range 39-74); positive for rheumatoid factor and/or anticyclic citrullinated peptide antibodies; disease duration < 6 mos (range 2-23 weeks)]. RAMRIS and serum biomarkers consisting of various experimental proteins including receptor activator of nuclear factor-κB ligand (RANKL) were obtained. Remission or treatment response was defined according to EULAR. To adjust for intrapersonal correlation, generalized linear mixed models were used.

Results: Treatment response at 3 months was associated to low RAMRIS erosion subscores and low total RAMRIS scores (p = 0.019 and 0.03, respectively). Remission at 6 months was associated to low RANKL levels (p = 0.033). In multivariate analyses, response at 3 and 6 months was predicted more accurately with the inclusion of total RAMRIS score, RAMRIS synovitis subscore at the second metacarpophalangeal (MCP) joint, or a combination of the two (p value likelihood ratio test = 0.035, 0.035, and 0.041, respectively). Remission was more accurately predicted with inclusion of RANKL, with no significant predictive effect of MRI.

Conclusion: Baseline total RAMRIS can predict EULAR response. RAMRIS synovitis subscore at the second MCP joint and RANKL are associated with response and remission, respectively.