Objectives: 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.
Methods: 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.
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.
Conclusions: 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.
Keywords: Acute-phase reactant; Metatarsophalangeal joint; Patient outcome assessment; Remission; Rheumatoid arthritis.