Prevalence, Comparative Risk, and Predictors of Shock in Children With Multisystem Inflammatory Syndrome Associated With COVID-19: A Systematic Review and Meta-Analysis.

BACKGROUND

Multisystem inflammatory syndrome in children (MIS-C) is a severe hyperinflammatory condition associated with SARS-CoV-2 infection and is frequently complicated by cardiovascular dysfunction, particularly shock. Early recognition of shock in MIS-C is critical to reduce morbidity and mortality.

OBJECTIVE

This systematic review and meta-analysis aimed to evaluate the prevalence, comparative risk, and predictors of shock among children with MIS-C, enhancing clinical management and informing future research.

METHODS

A systematic search of PubMed, Embase and Web of Science was conducted from database inception to 15 July 2025. Observational studies reporting prevalence, comparative risk or predictors of shock in children with MIS-C were included. Random-effects meta-analysis with Freeman-Tukey double arcsine transformation was used to estimate pooled prevalence with 95% confidence intervals (CI). Relative risks (RR) were pooled for comparative analyses. Subgroup analyses, sensitivity analyses and meta-regression were performed to explore heterogeneity. Publication bias was assessed using funnel plots and Egger's regression test.

RESULTS

Seventy studies involving 13 263 children with MIS-C were included. The pooled prevalence of shock was 56% (95% CI: 49%-63%), although substantial heterogeneity was observed (I 2 = 98.4%). Sensitivity analyses excluding studies with sample sizes < 50 and < 100 participants yielded pooled prevalence estimates of 50% (95% CI: 40%-59%) and 46% (95% CI: 33%-59%), respectively. Subgroup analyses demonstrated variation according to publication year and diagnostic criteria. Children with MIS-C had a significantly increased risk of shock compared with Kawasaki disease cohorts (RR = 8.52, 95% CI: 1.24-58.41; p < 0.05) and acute/severe COVID-19 cohorts without MIS-C (RR = 4.42, 95% CI: 2.44-8.02; p < 0.001). Echocardiographic abnormalities, myocardial dysfunction, elevated inflammatory markers and acute kidney injury were consistently associated with shock.

CONCLUSION

The certainty of evidence ranged from very low to low because of substantial heterogeneity, imprecision and methodological variability across studies. Despite these limitations, shock remains a frequent and serious complication of MIS-C, highlighting the importance of early cardiovascular assessment and timely recognition of high-risk children.