To compare MRI findings in rheumatoid arthritis (RA) patients treated with biologic disease-modifying anti-rheumatic drugs (DMARDs).
The study subjects were 43 RA patients treated with biologic DMARDs (13 with infliximab, 15 with tocilizumab, and 15 with abatacept). They were evaluated using Simplified Disease Activity Index (SDAI) and low-field extremity MRI at baseline, and at 24 weeks and 52 weeks of treatment.
Synovitis scores were significantly lower by 24 weeks in all groups, compared with baseline (P < 0.05). Significant improvement in bone marrow edema (BME) scores were noted from baseline to 24 weeks in infliximab and abatacept groups (P < 0.05), but from 24 weeks to 52 weeks in tocilizumab group (P < 0.01). No significant change was found in erosion score. The synovitis score at baseline correlated significantly with SDAI at 24 weeks (P < 0.05), and the score at 24 weeks correlated significantly with SDAI at 52 weeks (P < 0.05).
The results suggest that the inflammatory improvement by infliximab and abatacept may express earlier than those by tocilizumab, despite similar improvement in SDAI. MRI-detected synovitis could be a useful predictor of SDAI at 24 weeks of treatment. The MRI remains the best tool to detect and assess the effects of biologic DMARDs in RA.