Can Serum 25-Hydroxy Vitamin D Levels Predict the Severity of Multisystem Inflammatory Syndrome in Children and COVID-19?

Objective: To determine the clinical significance of serum 25-hydroxy (OH) vitamin D levels in pediatric patients with multisystem inflammatory syndrome in children (MIS-C) and compare the vitamin D levels of these patients with those patients with Coronavirus disease-2019 (COVID-19) and healthy controls. Methods: This study was designed for pediatric patients aged 1 month to 18 years and conducted between July 14 and December 25, 2021. Fifty-one patients with MIS-C, 57 who were hospitalized with COVID-19, and 60 controls were enrolled in the study. Vitamin D insufficiency was defined as a serum 25 (OH) vitamin D level of less than 20 ng/mL. Severe MIS-C was classified as necessitating intensive care due to cardiovascular instability, the necessity for non-invasive or invasive mechanical ventilation, and/or a diminishing Glasgow coma scale. World Health Organization definition criteria were used to describe the clinical stages of COVID-19 in children and patients were divided into four groups according to the clinical severity of COVID-19: asymptomatic, mild, moderate, and severe/critical. Results: The median serum 25 (OH) vitamin D was 14.6 ng/mL in patients with MIS-C, 16 ng/mL in patients with COVID-19, and 21.1 ng/mL in the control group (p