Incidence of multisystem inflammatory syndrome in children and the comorbidity scores in pediatric coronavirus disease 2019 cases.

Background: We aimed to determine the incidence of multisystem inflammatory syndrome in children (MIS-C) in pediatric coronavirus disease 2019 (COVID-19) cases and to define the relationships between the need for hospitalization, the development of MIS-C, and the Charlson Comorbidity Index (CCI) and Pediatric Comorbidity Index (PCI) scores.

Methods: All pediatric COVID-19 cases between March 25, 2020, and December 28, 2020, in the Marmara University Pendik Training and Research Hospital were enrolled. Patients who needed hospitalization were determined. Hospital records were re-examined to identify those diagnosed as having MIS-C. The CCI and PCI were used to validate the comorbidity status.

Results: Among 2,055 pediatric COVID-19 cases, 1,340 were included in the study, and 213 patients (15.9%) had at least one comorbidity. All the patients or their parents were interviewed about the need for hospitalization, except for the acute period. Six patients had MIS-C, which corresponds to a MIS-C incidence of 0.4%. The need for hospitalization increased in the patients with comorbidities (P < 0.05). No correlation was found between the comorbidity scores and the development of MIS-C. The need for hospitalization increased in the patients with CCI scores of ≥2 and PCI scores of ≥4 (P < 0.05).

Conclusions: Our study is the first to examine the incidence of MIS-C, which was 0.4%, by long-term follow up of pediatric COVID-19 cases and to demonstrate that the CCI and PCI can be used to predict the need for hospitalization and prognosis of pediatric patients with COVID-19.