Multisystem inflammatory syndrome in 1.2 million children: longitudinal cohort study of risk factors

Pediatr Res. 2024 Jan;95(1):325-333. doi: 10.1038/s41390-023-02633-y. Epub 2023 May 17.

Abstract

Background: We identified patient characteristics associated with an increased risk of developing MIS-C.

Methods: We conducted a longitudinal cohort study of 1,195,327 patients aged 0-19 years between 2006 and 2021, including the first two waves of the pandemic (February 25-August 22, 2020 and August 23, 2020-March 31, 2021). Exposures included prepandemic morbidity, birth outcomes, and family history of maternal disorders. Outcomes included MIS-C, Kawasaki disease, and other Covid-19 complications during the pandemic. We calculated risk ratios (RRs) and 95% confidence intervals (CIs) for the association between patient exposures and these outcomes using log-binomial regression models adjusted for potential confounders.

Results: Among 1,195,327 children, 84 developed MIS-C, 107 Kawasaki disease, and 330 other Covid-19 complications during the first year of the pandemic. Prepandemic hospitalizations for metabolic disorders (RR 11.3, 95% CI 5.61-22.6), atopic conditions (RR 3.34, 95% CI 1.60-6.97), and cancer (RR 8.11, 95% CI 1.13-58.3) were strongly associated with the risk of MIS-C, compared with no exposure. These same exposures were also associated with Kawasaki disease and other Covid-19 complications. However, birth characteristics and history of maternal morbidity were not associated with MIS-C development.

Conclusions: Children with pre-existing morbidity have a considerably elevated risk of MIS-C.

Impact: Morbidities that predispose children to multisystem inflammatory syndrome (MIS-C) are unclear. In this study, prepandemic hospitalizations for metabolic disorders, atopic conditions, and cancer were associated with an elevated risk of MIS-C. Birth characteristics and family history of maternal morbidity were not, however, associated with MIS-C. Pediatric morbidities may play a greater role in MIS-C onset than maternal or perinatal characteristics, and may help clinicians better recognize children at risk for this complication.

MeSH terms

  • COVID-19* / epidemiology
  • Child
  • Cohort Studies
  • Female
  • Humans
  • Longitudinal Studies
  • Metabolic Diseases*
  • Mucocutaneous Lymph Node Syndrome* / complications
  • Mucocutaneous Lymph Node Syndrome* / diagnosis
  • Mucocutaneous Lymph Node Syndrome* / epidemiology
  • Neoplasms*
  • Pregnancy
  • Risk Factors
  • Systemic Inflammatory Response Syndrome / epidemiology