To assess the utility of anti-melanoma differentiation-associated gene 5 (anti-MDA5) antibody measurement for predicting a risk for developing rapidly progressive interstitial lung disease (RP-ILD) in patients with polymyositis/dermatomyositis (PM/DM).
A single-center cohort of 64 consecutive Chinese patients with PM/DM was examined. Serum anti-MDA5 antibody was measured by enzyme-linked immunosorbent assay. For meta-analysis, we searched PubMed and the Institute for Scientific Information Web of Knowledge for original studies that measured anti-MDA5 antibodies in patients with PM/DM. We calculated pooled sensitivity, specificity, diagnostic odds ratio (DOR), and the summary receiver operating characteristic (sROC) curve.
In Chinese patients, anti-MDA5 antibodies were detected in 26 patients with classic DM or clinically amyopathic DM (CADM). Compared with anti-MDA5-negative patients, anti-MDA5-positive patients showed a higher prevalence of RP-ILD (P = 0.001). In a total of 233 patients with anti-MDA5 antibody, derived from 16 studies, a higher frequency of CADM was found in Japanese than in non-Japanese patients (74.7% versus 39.2%; P = 1.2 × 10(-7) ). Meta-analysis revealed that the pooled sensitivity and specificity of anti-MDA5 antibody for RP-ILD was 77% (95% confidence interval [95% CI] 64-87%) and 86% (95% CI 79-90%), respectively. The pooled DOR was 20.41 (95% CI 9.02-46.20) with a favorable area under the sROC curve of 0.89 (95% CI 0.63-0.98).
Detection of anti-MDA5 antibody is a valuable tool for identifying DM patients with a high risk for developing RP-ILD, but the distribution of classic DM and CADM in patients with this antibody varies among ethnic groups.