Does the multi-biomarker disease activity score have diagnostic value in early rheumatoid arthritis and unclassified arthritis?

The 2010 American College of Rheumatology (ACR) / European League Against Rheumatism (EULAR) updated classification criteria for rheumatoid arthritis (RA) focus on identifying patients at early disease stage.1 They facilitate early implementation of RA disease-modifying therapy, which has been associated with improved clinical and structural outcomes.2 ,3 Some patients with inflammatory oligoarthritis or polyarthritis initially not meeting RA classification criteria and classified with undifferentiated arthritis (UA) based on clinical and laboratory assessments, might later fulfil those criteria.4 Diagnosing these patients earlier would enable better therapeutic intervention and suppression of RA disease activity.5–7 The multi-biomarker disease activity (MBDA) score, calculated from the concentrations of 12 serum biomarkers, is an objective validated disease activity measure for patients with RA. It has been shown to track disease activity in patients with early and established RA, treatment-naive or not, and to associate with risk of radiographic progression.8 Here we investigated whether the MBDA score might inform RA diagnosis in patients with UA. We evaluated 126 patients from the prospective Synoviomics cohort9; 81 fulfilled ACR/EULAR 2010 criteria for RA and 45 …