Sociodemographic Disparities in Severity of Multisystem Inflammatory Syndrome in Children: The National Cross-Sectional MUltisystem Inflammatory Syndrome In Children (MUSIC) Study

Objective: To assess sociodemographic disparities associated with multisystem inflammatory syndrome (MIS-C) severity and adverse outcomes. Study design: This long-term outcomes after the MUltisystem Inflammatory Syndrome In Children (MUSIC) observational study included persons <21 years old with MIS-C hospitalized at 1 of 32 large US pediatric MUSIC medical centers. The primary outcome was a composite greater illness severity (eg, inotropic medications, intubations), and secondary outcomes were days from symptom onset to hospital admission and hospital length of stay (LOS). Predictor variables included patient distance to the hospital, neighborhood Social Deprivation Index, race and ethnicity, and non-primary English language. Results: Among 1115 patients with MIS-C, median age was 9 years (IQR 5.6, 12.7), 39.2% were female, 28.1% were non-Hispanic Black, 27.8% were Hispanic, and 47.3% had public insurance. On multivariable analysis, more severe illness was seen among Hispanic patients (OR 1.5; 95% CI 1.1-2.2); non-Hispanic Black race (OR 1.7; 95% CI 1.2-2.4), and ages 13-21 years (OR 3.7; 95% CI 2.4-5.7). Longer time from symptom onset to hospital admission was associated with farther distance from hospital (P =.006). Risk factors for longer hospital LOS were adolescent age (≥13 years; P =.002), and non-Hispanic Black race (P =.018). Conclusions: Disparities in MIS-C severity outcomes and hospital LOS were associated with older age and being Black and/or Hispanic. Given the ongoing and newer strains of COVID-19, it is important to understand disease severity and disparities in outcomes due to MIS-C.