Clinical and Laboratory Parameters Associated with PICU Admission in Children with Multisystem Inflammatory Syndrome Associated with COVID-19 (MIS-C)

<b>Background/Objectives:</b> Multisystem Inflammatory Syndrome in children (MIS-C) is a rare but severe post-infectious complication of COVID-19 that often requires admission to the Pediatric Intensive Care Unit (PICU). The present study aimed to compare the demographic, clinical, and laboratory characteristics of children diagnosed with MIS-C who were admitted to the PICU and those who did not require PICU admission. <b>Methods:</b> Children diagnosed with MIS-C from September 2020 to April 2023 were included in this case-control study. Demographic, clinical, and laboratory data were collected from medical records. <b>Results:</b> Fifty children with MIS-C were included in the study [median (IQR) age: 7.5 (4.3, 11.4) years, 28/50 (56%) males]. Twenty-two (22/50, 44%) children required admission to the PICU. In the multivariate regression analysis, hepatic (OR: 12.89, 95%CI: 1.35-123.41, <i>p</i>-value = 0.03) and cardiological involvement (OR: 34.55, 95%CI: 2.2-541.91, <i>p</i>-value = 0.01) were significantly associated with hospitalization at the PICU. Regarding the laboratory and imaging parameters during the first 48 h from admission, D-dimer levels higher than 4 μg/mL and decreased Left Ventricular Ejection Fraction (LVEF) were associated with an increased risk of PICU admission (OR: 7.95, 95%CI: 1.48-42.78, <i>p</i>-value = 0.02 and OR = 1.28, 95%CI: 1.07-1.53, <i>p</i>-value = 0.01). Children who were admitted to the PICU were more likely to develop complications during their hospitalization (10/22, 45.5% vs. 3/28, 10.7%, <i>p</i>-value = 0.005) and were hospitalized for more days than children in the pediatric ward (median length of stay (IQR): 20 (15, 28) days vs. 8.5 (6, 14) days, <i>p</i>-value < 0.001). <b>Conclusions:</b> The findings of this study indicate that cardiovascular and hepatic involvement and increased D-dimer levels in children with MIS-C might be associated with admission to the PICU.