Bone marrow oedema predicts structural progression in a 1-year follow-up of 85 patients with RA in remission or with low disease activity with low-field MRI

Objectives To identify the predictive factors of MRI-determined structural progression in patients with rheumatoid arthritis (RA) in remission or with low disease activity (LDA). Methods In this 1-year longitudinal study, patients with RA in clinical remission (disease activity score (DAS) 44 <= 1.6) or with LDA (1.6< DAS 44 <= 2.4) underwent low-field MRI of the dominant hand at baseline and at 6 and 12 months. MRI images were scored by the rheumatoid arthritis MRI system (RAMRIS) by rheumatologists blind to clinical and biological data. Structural progression was defined as a change in the RAMRIS erosion score between baseline and 1 year greater than the smallest detectable difference. Predictive factors of structural disease progression were analysed by logistic and linear regression. Results 85 patients with RA in remission (n= 47) or with LDA (n= 38) were included. Their mean age was 50 +/- 13 years, 81% were female, mean disease duration was 35 +/- 20 months, rheumatoid factor (RF)/anti-CCP positivity was 63%/64% and 77% had radiographic erosion. At baseline most patients showed inflammatory activity on MRI: 87% had at least one synovitis and 23% at least one location of bone marrow oedema (BME). BME at baseline was predictive of change in RAMRIS(erosion) (OR 1.25, 95% CI 1.09 to 1.43, p= 0.0013, area under the curve= 0.78). Conclusion BME is a predictive factor of MRI-determined structural progression in patients with RA in clinical remission or with LDA.