Autoantibodies to cyclic citrullinated peptides predict progression to rheumatoid arthritis in patients with undifferentiated arthritis: A prospective cohort study

Rheumatoid arthritis (RA) is a common, severe, chronic inflammatory joint disease. Since the disease may initially be indistinguishable from other forms of arthritis, early diagnosis can be difficult. Autoantibodies seen in RA can be detected years before clinical symptoms develop. In an inception cohort of patients with recent-onset arthritis, we undertook this study to assess the predictive value of RA-specific autoantibodies to cyclic citrullinated peptides (CCPs) in patients with undifferentiated arthritis (UA).

Anti-CCP2 antibody tests were performed at baseline in 936 consecutive, newly referred patients with recent-onset arthritis. Patients who could not be properly classified 2 weeks after inclusion were categorized as having UA. Patients with UA were followed up for 3 years and evaluated for progression of their disease to RA as defined by the American College of Rheumatology (ACR) 1987 revised criteria.