SAT0523 Prediction of Clinical Response to Biologics in Rheumatoid Arthritis by Baseline Magnetic Resonance Imaging (MRI) of the Wrist: a Cohort Study Associating MRI Synovitis Score with Clinical Outcome
Authors: S. H. Kamp, R. Christensen, H. Bliddal, M. Østergaard, R. Bouert, M. Boesen
Journal: Annals of the Rheumatic Diseases (2013)

<h3>Background</h3> MRI is currently the imaging gold standard reference for visualization of the inflammatory status of the affected joints in patients with rheumatoid arthritis (RA) [1]. The OMERACT-RA MRI Scoring System (RAMRIS) [2] is the recommended MRI scoring method for clinical trials. The reliability of this system has been evaluated in a number of studies [1], but its ability to predict the clinical effect of biological treatment is not yet clarified. <h3>Objectives</h3> To investigate the ability of the OMERACT RAMRIS synovitis score, to predict the clinical outcome (EULAR response) of biologic treatment after 6 months on therapy. <h3>Methods</h3> All RA patients starting biological therapy at Frederiksberg Hospital between 2006 and 2010 with a valid MRI scan of the dominant wrist before initiation of biological therapy, and a record available in the DANBIO registry, were included. Clinical data at baseline and 6 months follow-up were extracted from the DANBIO registry. The MRI was scored according to the OMERACT-RAMRIS criteria. Patients were grouped into high (&gt;6) or low-moderate (≤6) synovitis score, and the Relative Risk (RR, with 95% CI) for treatment response according to the EULAR response criteria was calculated. Missing data were replaced by non-responder imputation. <h3>Results</h3> 106 patients fulfilled the inclusion criteria; 61% received infliximab, 30% etanercept, 7% adalimumab, 1% rituximab and 1% tocilizumab. Of these, 76 had low-moderate and 30 high MRI synovitis score. Patients in the high-synovitis group had significantly higher clinical disease activity at baseline (DAS28 (median (interquartile range)) = 5.4 (4.7 -6.1) vs. 4.7 (4.1-5.3) p= 0.005), but were also older, had longer disease duration and a higher MRI bone edema and bone erosion score. 86 patients completed the study. The likelihood of responding in the high synovitis group vs. the low-to-moderate synovitis group was RR=1.30 (0.75-2.24, p=0.35) for a good EULAR response, 1.55 (0.83-2.89, p=0.170) for a moderate EULAR, and the high synovitis group had a significantly lower risk of not responding to treatment (RR=0.25 (0.06-0.98), p=0.046; EULAR no response). <h3>Conclusions</h3> High OMERACT- RAMRIS scores for synovitis in the wrist joint are related to high overall clinical disease activity. Lower pre-treatment MRI synovitis score was associated with lower clinical effect after 6 months of biological treatment in RA patients. <h3>References</h3> Boesen, M., et al., <i>MRI quantification of rheumatoid arthritis: current knowledge and future perspectives.</i> Eur J Radiol, 2009. Ostergaard, M., et al., <i>OMERACT Rheumatoid Arthritis Magnetic Resonance Imaging Studies. Core set of MRI acquisitions, joint pathology definitions, and the OMERACT RA-MRI scoring system.</i> J Rheumatol, 2003. <h3>Disclosure of Interest</h3> None Declared