Objective: To evaluate the diagnostic value of anti-cyclic citrullinated peptide (CCP) antibody for rheumatoid arthritis.
Methods: Data about RA from January 2000 to December 2005 were retrieved through Cochrane Library, Pubmed database, Excerpta Medica Database (EMBASE), OVID database, and China National Knowledge Infrastructure (CNKI), especially through the Annul of the Rheumatic Disease and relevant gray literatures, by entering the words "cyclic citrullinated peptides", "rheumatoid arthritis", "sensitivity", and "specificity". The inclusion of qualified literatures was based on the criteria for diagnostic research recommended by the Cochrane Methods Group on Screening and Diagnostic Test. Statistical analysis wes performed by employing the softwares of MATLAB and Review Manager 4, 2, and summary receiver operation characteristic (SROC) curve method.
Results: Twenty-two articles, 15 in English and 7 in Chinese, were extracted. The reported sensitivity of anti-CCP for the diagnosis of RA ranged from 39.2% to 84.6%, and the reported specificity ranged from 90% to 97.9%. The heterogeneity of the included articles was tested, a proper effect model was selected to calculate the pooled weighted sensitivity and specificity with 95% confidence interval for anti-CCP antibody as 77.3% (63.1%, 89.2%) and 93.85% (85.5%, 98.1%), and the positive and negative likelihood ratios as 12.0 and 0.24 respectively. The area under the curve of SROC was 0.8976, and the Q value was 0.87. The sensitivity of the patients with the duration of illness < 1 year was 43%, significantly lower than that of the patients with a duration of illness > 1 year (70.2%, P < 0.01); and the specificity of the patients with the duration of illness < 1 year was 94.2%, not significantly different from that of the patients with the duration of illness > 1 year (95.2%, P = 0.94).
Conclusion: With relatively high sensitivity and specificity, anti-CCP antibody may be a useful parameter in the clinical diagnosis pf RA.