The International RA BIODAM Cohort for Validation of Soluble Biomarkers in Rheumatoid Arthritis: Cohort Description

Objective The OMERACT Soluble Biomarker Working Group initiated an international, multicenter, prospective study, The Rheumatoid Arthritis (RA) BIODAM cohort (NCT01476956), to generate resources for the clinical validation of candidate biomarkers predictive of radiographic progression. This first report describes the cohort, clinical outcomes, and radiographic findings. Methods RA patients from 38 sites in 10 countries starting or changing conventional synthetic diseasemodifying anti-rheumatic (csDMARDs) drugs and/or starting tumor necrosis factor inhibitor (TNFi) reserved. 5 were followed for 2 years. Participating physicians were required to adhere to a treat-to-target strategy. Biosamples (serum, urine) were acquired every 3 months, radiography of hands and feet every 6 months, and ultrasound of hands and feet every 3 months in a subset. Primary endpoint was radiographic progression by the Sharp van der Heijde (vdHm-SHS) score. Results A total of 571 patients were recruited and 439 (76.9%) completed 2-year follow-up. At baseline, the majority was female (76%), mean age 55.7 years, and mean disease duration 6.5 years. Patients had a mean of 8.4 swollen and 13.6 tender joints, DAS44 3.8, 77.7% rheumatoid factor (RF) or anti-citrullinated peptide antibody (ACPA) positive. Percentage of patients in DAS and ACR remission at 2 years was 52.2% and 27.1%, respectively. Percentage of patients with radiographic progression (>0.5) at 1- and 2-years was 38.3% and 59.8%, respectively. Conclusion The RA-BIODAM prospective study succeeded in generating an extensive list of clinical, imaging (2343 radiographs), and biosample (4638 sera) resources that will be made available to expedite the identification and validation of biomarkers for radiographic damage endpoints.