MicroRNAs as diagnostic and prognostic biomarkers for viral myocarditis: A systematic review and meta-analysis

Background Current diagnostic tools for viral myocarditis (VM) present significant limitations. Recent studies have shown that microRNAs (miRNAs) are promising circulating biomarkers. The aim of this meta-analysis is to evaluate the diagnostic and prognostic role of miRNAs in VM. Methods A systematic literature search was conducted across five databases (PubMed, Scopus, Embase, Google Scholar, and the Cochrane Library). Eligible studies reported miRNA diagnostic and/or prognostic accuracy in human subjects with VM diagnosis. Methodological quality of the included studies was assessed using the QUADAS-2 tool. Pooled estimates of area under the curve (AUC), sensitivity, specificity, and summary receiver operating characteristic (SROC) curves were calculated. Results A total of 26 studies were included in our analysis; 42 differentially expressed miRNAs were identified; 30 exhibited upregulated expression, 9 demonstrated downregulation, and 3 had variable expression patterns. The pooled diagnostic AUC for VM was 0.897 (0.863–0.931; I 2 = 93.4%); bivariate analysis yielded a pooled sensitivity of 0.758 (0.582–0.876; I 2 = 87.1%) and specificity of 0.881 (0.811–0.928; I 2 = 78.5%). Regarding fulminant myocarditis (FM) detection, the pooled AUC was 0.883 (95% CI: 0.837–0.930; I 2 = 87.3%). Conclusions Circulating miRNAs represent promising candidate biomarkers for the diagnosis of VM, although the available evidence remains preliminary. Further large-scale prospective studies are needed to reproduce and validate these results.