Abstract

Presentation Number: 168

Floris A. van Gaalen1, Suzanne P. Linn-Rasker1, Walther J. van Venrooij2, Ben A. de Jong2, Ferdinand C. Breedveld1, Cor L. Verweij3, René E. M. Toes1, Tom W. J. Huizinga1. 1Dept. of Rheumatology, LUMC, Leiden, Netherlands; 2Dept. of Biochemistry, University of Nijmegen, Nijmegen, Netherlands; 3Dept. of Molecular Cell Biology, VUMC, Amsterdam, Netherlands

Purpose: Rheumatoid arthritis (RA) is a common, severe, chronic inflammatory joint disease. As 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 assessed the predictive value of RA specific autoantibodies to cyclic citrullinated peptides (CCP) in patients with undifferentiated arthritis (UA).

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

Results: Three hundred and eighteen patients out of 936 recent onset arthritis patients were classified as UA and were available for analysis. After 3 years of follow-up 40% (127/318) UA patients had been classified as RA. RA had developed in 25% (63/249) of patients with a negative anti-CCP test and in 93% (64/69) of patients with a positive anti-CCP test (odds ratio 37.8 (95% CI 13.8–111.9)). Multivariate analysis of the presence of anti-CCP antibodies and parameters from the ACR criteria identified polyarthritis, symmetric arthritis, erosions on radiographs and CCP antibodies as significant predictors of RA.

Conclusion: Testing for anti-CCP antibodies in UA allows accurate prediction of a substantial number of patients that will fulfill the ACR criteria for RA.

Disclosure: F.A. van Gaalen, None; S.P. Linn-Rasker, None; W.J. van Venrooij, None; B.A. de Jong, None; F.C. Breedveld, None; C.L. Verweij, None; R.E.M. Toes, None; T.W.J. Huizinga, None.