To determine the prevalence and distribution of signs of synovitis in the residual joints in remission defined by the American College of Rheumatology/European League Against Rheumatism (ACR/EULAR) rheumatoid arthritis (RA) remission criteria and the role of their components in preventing misclassification due to reduced joint count.
The cross-sectional observational data of RA patients including full joint counts were analyzed. Definitions of remission used were the ACR/EULAR RA remission criteria and their modifications using full joint counts with the same thresholds of the items and the calculated results.
A total of 304 RA patients with 3,149 observations could be analyzed. Patients in remission according to the ACR/EULAR remission criteria can still show residual disease activity in the feet in up to 27% of the population with a 28-joint count remission. Residual disease activity has no impact on patient's global assessment for current disease activity, when signs of concomitant ankle joint synovitis were absent.
RA patients in remission according to the ACR/EULAR definitions can still show signs of synovitis mostly in the forefeet joints. Acute-phase reactants and patient's global assessment for current disease activity have little impact in mitigating the limitation of reduced joint count.