Factors Differentiating Multisystem Inflammatory Syndrome in Children (MIS-C) From Severe/Critical COVID-19 Infection in Children

OBJECTIVE: To differentiate severe/critical coronavirus disease 2019 (COVID-19) infection from multisystem inflammatory syndrome in children (MIS-C). METHODS: Single-center chart review comparing characteristics of children with MIS-C and ‘severe/critical’ COVID-19 infection. Multivariate logistic regression was performed to create predictive models for predicting MIS-C. RESULTS: Of 68 patients, 28 (41.2%) had MIS-C while 40 (58.8%) had severe/critical COVID-19 infection. MIS-C patients had a higher prevalence of fever, mucocutaneous, cardiac and gastrointestinal involvement and a lower prevalence of respiratory symptoms (P<0.05). Significantly lower hemoglobin, platelet count, serum electrolytes, and significantly elevated inflammatory and coagulation markers were observed in MIS-C cohort. Upon multivariate logistic regression, the best model included C-reactive protein (CRP), platelet count, gastrointestinal and mucocutaneus involvement and absence of respiratory involvement (performance of 0.94). CRP>40 mg/L with either platelet count <150×10(9) or mucocutaneous involvement had specificity of 97.5% to diagnose MIS-C. CONCLUSION: Elevated CRP, thrombocytopenia and mucocutaneous involvement at presentation are helpful in differentiating MIS-C from severe COVID-19. ELECTRONIC SUPPLEMENTARY MATERIAL: Supplementary material is available for this article at 10.1007/s13312-022-2442-4 and is accessible for authorized users.