The use of MRI-detected synovitis to determine the number of involved joints for the 2010 ACR/EULAR classification criteria for Rheumatoid Arthritis - is it of additional benefit?

OBJECTIVE: To assess the value of MRI-detected synovitis to determine the number of involved joints on the performance of the 2010-ACR/EULAR classification criteria for rheumatoid arthritis (RA).
METHODS: 277 patients with a clinical suspicion of RA consecutively included in the Leiden Early Arthritis Clinic (EAC)-cohort underwent 1.5T MRI of MCP-, wrist- and MTP-joints. Test characteristics of the 2010-criteria were calculated when the number of involved joints was determined with and without including MRI-detected synovitis. Two outcomes were studied: disease modifying anti-rheumatic drug (DMARD)-initiation and 1987-criteria fulfilment during the first year.
RESULTS: At baseline, 143 patients were classified as RA. When MRI-detected synovitis was considered, 14 patients additionally fulfilled the 2010-criteria. Of these, 64% (9/14) started DMARDs. When MRI-detected synovitis was also used to determine the number of involved joints the sensitivity changed from 62% to 67%, the specificity from 90% to 84% and the AUC from 0.76 to 0.75. The net reclassification index was -2.4%. When fulfilling the 1987-criteria was used as outcome, results were similar.
CONCLUSION: We found no scientific support that the use of MRI-detected synovitis is of additional benefit for the performance of the 2010 classification criteria. © Article author(s) (or their employer(s) unless otherwise stated in the text of the article) 2018. All rights reserved. No commercial use is permitted unless otherwise expressly granted.