Background/Purpose: Magnetic resonance imaging ( MRI ) in rheumatoid arthritis ( RA ) has been shown to be more sensitive than clinical and radiological parameters in evaluating disease activity levels and chronic joint damage. Few studies have illustrated the impact of conventional and biologic DMARDs on the MRI findings of RA, including osteitis ( bone marrow edema ), synovitis and bone erosions. The objectives of this study were to compare MRI findings among groups of RA patients treated with conventional systemic DMARD ( csDMARD ) monotherapy, csDMARD multi-therapy and combination biologic and conventional DMARD therapies over a two year study period.

Methods: Magnetic resonance images were acquired of the dominant hand of 51 RA patients from a single rheumatology clinic at baseline and at follow-up over an average time of 23 months. Images were obtained using a 1T magnet, 100nm cylindrical transmit and receive coil and a 3D spoiled gradient echo sequence. RAMRIS scoring for bone marrow edema, synovitis and bone erosion was performed for the 2^nd through 5^thMCP joints at baseline and follow-up as well as clinical disease activity scores ( CDAI ). DMARD ( biologic and conventional ) history for all patients was obtained and the patients were grouped into four categories based on their exposure: 1. DMARD mono-therapy with methotrexate ( MTX ), 2. DMARD mono-therapy with hydroxychloroquine ( HCQ ), 3. DMARD multi-therapy ( multiDMARD ) and 4. Biologic and conventional DMARD multi-therapy ( DMARDbio ). Multivariable linear regression analyses were conducted to determine differences in synovitis, edema and erosion scores at follow-up. The analyses were adjusted for baseline values.

Results: The MTX, HCQ, DMARDbio and multiDMARD groups had 12, 5, 21 and 13 patients respectively. Average CDAI scores at baseline were 10.9, 7.3, 19.0 and 36.5 for MTX, HCQ, multiDMARD and DMARDbio groups respectively. The average baseline and follow-up RAMRIS scores for all groups are listed in table 1 with asterisks denoting statistical significance ( p < 0.05 ) versus MTX group.

Table 1: RAMRIS scores at baseline and follow-up (* p value < 0.05 vs MTX)

Conclusion: In this prospective cohort of rheumatoid arthritis patients treated with four different regimens, we noted a significant difference in all RAMRIS scoring over an average 23 month period in the multiDMARD therapy group versus MTX group. The baseline CDAI score of the multiDMARD group was higher than the MTX group. The need for multiple DMARDs during this study period may have been because of the higher disease activity in this group. Despite multiple therapies, there was worsening of disease activity based on the RAMRIS scores in this group, which likely was accounted for by the significantly higher baseline disease activity. The MTX group was a suitable control considering the stable RAMRIS scores from baseline to follow-up. The DMARDbio group had higher clinical disease activity score than all other groups at baseline with a CDAI of 36.5. There was a significant difference in RAMRIS synovitis score in the DMARDbio group over the study period versus MTX group but other RAMRIS scores were not significant. This would suggest that biologic DMARD therapy has higher efficacy in suppressing disease activity versus multiple csDMARD therapy. Further studies will be needed to determine the impact of therapy on disease activity as measured by MRI studies.

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ACR Meeting Abstracts - https://acrabstracts.org/abstract/magnetic-resonance-imaging-measures-of-disease-activity-in-rheumatoid-arthritis-patients-treated-with-multiple-regimens-of-dmard-therapy/