Easy and accurate diagnosis of rheumatoid arthritis using anti-cyclic citrullinated peptide 2 antibody, swollen joint count, and C-reactive protein/rheumatoid factor
Yamane, T.; Hashiramoto, A.; Tanaka, Y.; Tsumiyama, K.; Miura, Y.; Shiozawa, K.; Chihara, K.; Shiozawa, S.
Journal of Rheumatology 35(3): 414-420
2008
ISSN/ISBN: 0315-162X PMID: 18203327 Document Number: 621174
Objective. To determine an easy-to-use diagnostic criterion for early rheumatoid arthritis (RA) that may be useful for general physicians, using anti-cyclic citrullinated peptide (CCP) antibody.Methods. We prospectively studied 435 patients who first visited the hospital with arthritic symptoms within 24 months, including 264 visitors within 6 months. The diagnosis was made on their first visit by examination and laboratory tests including anti-CCP antibodies, rheumatoid factor (RF) and C-reactive protein (CRP), and radiograph.Results. The diagnostic specificity and positive predictive value (PPV) of anti-CCP2 assay were 94.9% and 87.8%, respectively, and those of anti-CCP2 plus RF were 96.9% and 90.9% for the patients who first visited having morning stiffness, arthralgia, and/or joint swelling within 3 months from onset (n = 165). For the patients who first visited later, but within 24 months from onset (n = 260), the diagnostic specificity and PPV were extremely high, 98.7% and 95.5%, when anti-CCP2 assay was coevaluated with RF, CRP, and more than 3 swollen joints. Respective combinations of anti-CCP2 assay plus either 2 of 3 measures were also highly specific.Conclusion. A diagnostic criterion including anti-CCP2 assay in combination with RF, CRP, and/or swollen joints is less sensitive but highly specific, and accurately predicts future development of RA among those with arthritic symptoms who first consulted doctors within 2 years after onset. It should be highly useful for the general physician without special techniques or devices.