359 - Anti-CCP2 Assay Accurately Predicts Future Development Of Rheumatoid Arthritis as Early as 3 Months From Onset Of Arthritic Symptoms

Takashi Yamane1, Kazuko Shiozawa2, Akira Hashiramoto1, Yasushi Tanaka2, Ken Tsumiyama1, Yasushi Miura1, Shunichi Shiozawa1. 1Kobe University FHS School of Medicine, Kobe, Japan; 2Rheumatic Disease Centre, Konan Kakogawa Hospital, Kakogawa, Japan
Presentation Number: 359

PURPOSE The early and accurate predictor of the future development of rheumatoid arthritis (RA) was sought for in the patients who first visited hospital complaining any of arthritic symptoms after several months from onset.
METHODS 435 patients who first visited hospital within 24 months after the onset of arthritic symptoms, including 261 first visitors within 6 months, were studied prospectively for 9.2±11.0 months. Anti-CCP antibody (Ab) was measured by anti-CCP2 ELISA simultaneously with other clinical and laboratory parameters on their first visit.
RESULTS The frequency of anti-CCP2-positive individual was 50.0% at 1 month from onset and was gradually increased during disease course in the patients with final diagnosis of RA. For the patients who first visited hospital within 3 months from onset, the diagnostic specificity and positive predictive value (PPV) of anti-CCP2 assay, a predictor for future development of RA, were 95.4% and 87.8%. Those of anti-CCP2 assay plus rheumatoid factor (RF) were 97.2% and 90.9%. For the patients who first visited later than 3 months but within 24 months from onset, however, predictive accuracy of anti-CCP assay declined. Accordingly, we sought for another criteria and found that the specificity and PPV were 98.7% and 95.5%, respectively, when anti-CCP2 assay was co-evaluated with RF, C-reactive protein (CRP) and swollen joints. These values surpassed those of ACR criteria, and thus one can predict future development of RA with high accuracy. For routine clinical use, co-evaluation of anti-CCP2 assay either with: (1) RF plus swollen joints; (2) CRP plus swollen joints; or (3) RF plus CRP would also be highly accurate enough, which gave the specificity and PPV values exceeding 96% and 92%, respectively.
CONCLUSIONS Anti-CCP2 assay accurately predicts future development of RA from as early as 3 months until 24 months from onset of arthritic symptoms when RF, CRP and/or swollen joints are co-evaluated. Routine clinical use of anti-CCP2 assay is highly recommended.

 T. Yamane, None.