Meta-analysis: diagnostic accuracy of antibody against peptidylarginine deiminase 4 by ELISA for rheumatoid arthritis

The antibody against peptidylarginine deiminase (PAD) 4 is a biomarker that might be helpful in the diagnosis of rheumatoid arthritis (RA). We aim to estimate the diagnostic value of anti-PAD4 antibody for RA by meta-analysis. We searched PubMed, Embase, the Cochrane Library, Web of Science, and Scopus for studies published in any languages in March 1, 2017 that evaluated the diagnostic accuracy of the anti-PAD4 antibody for the diagnosis of RA. The articles that detected the anti-PAD4 antibody by enzyme-linked immunosorbent assay (ELISA) and used healthy donors or patients without arthritis or arthralgia as controls were included for meta-analysis. The articles were assessed by Quality Assessment of Diagnostic Accuracy Studies tool. A bivariate mixed-effects model was used to summarize the diagnostic indexes from eight eligible studies. The pooled sensitivity, specificity, and positive and negative likelihood ratios for anti-PAD4 antibody were 38% (95% CI 30.0–46.0%), 96% (95% CI 93.0–98.0%), 8.96 (95% CI 5.00–16.05), and 0.65 (95% CI 0.57–0.74), respectively. The summary diagnostic odds ratios were 13.74 (95% CI 7.23–26.09), and the area under the summary receiver operator characteristic curve was 86% (95% CI 83–89%). Anti-PAD4 antibody detected by ELISA shows a high value in the diagnosis of RA with high specificity, but relatively low sensitivity.