Systematic review and meta-analysis on the serological, immunological, and cardiac parameters of the multisystem inflammatory syndrome (MIS-C) associated with SARS-CoV-2 infection

Diverse clinical and laboratory features of multisystem inflammatory syndrome (MIS-C) have been reported in the literature. Despite the worldwide distribution, systemic studies regarding the laboratory results do not exist. Therefore, we aimed to perform this systematic review and meta-analysis to evaluate the serological, immunological, and cardiac parameters of the MIS-C associated with SARS-CoV-2 infection. We searched the PubMed, Scopus, and Web of Science databases using specific keywords for any papers published in English since the disease onset and the first report until July 19, 2020. The inclusion criteria were children <21 years diagnosed with MIS-C without any limitation on defining criteria. Forty-eight studies were included in the final analysis, with a total population size of 3543 children with MIS-C. The median age of the included patients was 8.3 (6.7-9) years. The pooled prevalence of male patients was 59% (95% CI: 56%-61%) and 62% (95% CI: 55%-69%) were admitted in ICU. The pooled prevalence of positive SARS-CoV-2 RT-PCR, SARS-CoV-2 IgM, and SARS-CoV-2 IgG antibody tests was 33% (95% CI: 27%-40%), 39% (95% CI: 22%-58%) and 81% (95% CI: 76%-86%), respectively. The positivity rate of the inflammatory markers was as follows: CRP (96%, 95% CI: 90%-100%), d-dimer (87%, 95% CI: 81%-93%), ESR (81%, 95% CI: 74%-87%), procalcitonin (88%, 95% CI: 76%-97%), ferritin (79%, 95% CI: 69%-87%), and fibrinogen (77%, 95% CI: 70%-84%). The pooled prevalence of elevated brain natriuretic peptide (BNP) level, pro-BNP, and troponin were found in 60% (95% CI: 44%-75%), 87% (95% CI: 75%-96%), and 55% (95% CI: 45%-64%), respectively. The majority of patients had positive SARS-CoV-2 IgG test. Nearly one-third of the cases showed negative RT-PCR results. Cardiac and inflammatory markers were elevated in the majority of cases. These findings suggest that hyperinflammation and cardiac dysfunction are common complications of MIS-C.