Utility of Anti–Melanoma Differentiation–Associated Gene 5 Antibody Measurement in Identifying Patients With Dermatomyositis and a High Risk for Developing Rapidly Progressive Interstitial Lung Disease: A Review of the Literature and a Meta‐Analysis

Objective 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). Methods 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. Results 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). Conclusion 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.