Racial and Ethnic Disparities in Multisystem Inflammatory Syndrome in Children in the United States, March 2020 to February 2021

BACKGROUND

The incidence of multisystem inflammatory syndrome in children (MIS-C) varies by race and ethnicity. This study assessed whether disparities in MIS-C in the United States by race and ethnicity exceed known disparities in coronavirus disease 2019 (COVID-19) incidence.

METHODS

We compared the distribution of race and ethnicity among patients with MIS-C (<21 years of age, termed children) with onset March 2020 to February 2021 to that of children with COVID-19 and in the general population. Analysis was restricted to 369 counties with high completeness of race and ethnicity reporting for MIS-C and COVID-19. For each racial and ethnic group, observed numbers of patients with MIS-C were compared with expected numbers (observed/expected ratio) in children with COVID-19 and in the general population within these counties.

RESULTS

Compared with children in the general population, MIS-C was more frequent among Hispanic (139% of expected) and non-Hispanic Black children (183%) and less frequent among non-Hispanic White (64%) and non-Hispanic Asian children (48%). Compared with children with COVID-19, MIS-C was more frequent in non-Hispanic Black children (207% of expected) and less frequent in non-Hispanic White children (68%); however, frequency was not different among Hispanic (102%) and non-Hispanic Asian (74%) children.

CONCLUSIONS

Disparities in MIS-C by race and ethnicity exist, even after controlling for COVID-19 disparities and geographic variations. The high proportion of MIS-C among Hispanic children and low proportion among non-Hispanic Asian children align with COVID-19 rates, while the high proportion among non-Hispanic Black children and low proportion among non-Hispanic White children are not explainable by COVID-19 rates.

Factors linked to severe outcomes in multisystem inflammatory syndrome in children (MIS-C) in the USA: a retrospective surveillance study

Background

Multisystem inflammatory syndrome in children (MIS-C) is a newly identified and serious health condition associated with SARS-CoV-2 infection. Clinical manifestations vary widely among patients with MIS-C, and the aim of this study was to investigate factors associated with severe outcomes.

Methods

In this retrospective surveillance study, patients who met the US Centers for Disease Control and Prevention (CDC) case definition for MIS-C (younger than 21 years, fever, laboratory evidence of inflammation, admitted to hospital, multisystem [≥2] organ involvement [cardiac, renal, respiratory, haematological, gastrointestinal, dermatological, or neurological], no alternative plausible diagnosis, and either laboratory confirmation of SARS-CoV-2 infection by RT-PCR, serology, or antigen test, or known COVID-19 exposure within 4 weeks before symptom onset) were reported from state and local health departments to the CDC using standard case-report forms. Factors assessed for potential links to severe outcomes included pre-existing patient factors (sex, age, race or ethnicity, obesity, and MIS-C symptom onset date before June 1, 2020) and clinical findings (signs or symptoms and laboratory markers). Logistic regression models, adjusted for all pre-existing factors, were used to estimate odds ratios between potential explanatory factors and the following outcomes: intensive care unit (ICU) admission, shock, decreased cardiac function, myocarditis, and coronary artery abnormalities.

Findings

1080 patients met the CDC case definition for MIS-C and had symptom onset between March 11 and Oct 10, 2020. ICU admission was more likely in patients aged 6–12 years (adjusted odds ratio 1·9 [95% CI 1·4–2·6) and patients aged 13–20 years (2·6 [1·8–3·8]), compared with patients aged 0–5 years, and more likely in non-Hispanic Black patients, compared with non-Hispanic White patients (1·6 [1·0–2·4]). ICU admission was more likely for patients with shortness of breath (1·9 [1·2–2·9]), abdominal pain (1·7 [1·2–2·7]), and patients with increased concentrations of C-reactive protein, troponin, ferritin, D-dimer, brain natriuretic peptide (BNP), N-terminal pro B-type BNP, or interleukin-6, or reduced platelet or lymphocyte counts. We found similar associations for decreased cardiac function, shock, and myocarditis. Coronary artery abnormalities were more common in male patients (1·5 [1·1–2·1]) than in female patients and patients with mucocutaneous lesions (2·2 [1·3–3·5]) or conjunctival injection (2·3 [1·4–3·7]).

Interpretation

Identification of important demographic and clinical characteristics could aid in early recognition and prompt management of severe outcomes for patients with MIS-C.

Funding

None.

Multisystem Inflammatory Syndrome in Children Associated with Severe Acute Respiratory Syndrome Coronavirus 2: A Systematic Review

OBJECTIVE

To develop a more comprehensive description of multisystem inflammatory syndrome in children (MIS-C), a novel syndrome linked to severe acute respiratory syndrome coronavirus 2, by conducting a systematic analysis of studies from different settings that used various inclusion criteria.

STUDY DESIGN

MIS-C studies were identified by searching PubMed and Embase as well as preprint repositories and article references to identify studies of MIS-C cases published from April 25, 2020, through June 29, 2020. MIS-C study metadata were assessed and information on case demographics, clinical symptoms, laboratory measurements, treatments, and outcomes were summarized and contrasted between studies.

RESULTS

Eight studies were identified representing a total of 440 MIS-C cases. Inclusion criteria varied by study: 3 studies selected patients diagnosed with Kawasaki disease, 2 required cardiovascular involvement, and 3 had broader multisystem inclusion criteria. Median age of patients by study ranged from 7.3 to 10 years, and 59% of patients were male. Across all studies, the proportion of patients with positive results for severe acute respiratory syndrome coronavirus 2 reverse transcriptase-polymerase chain reaction tests ranged from 13% to 69% and for serology, from 75% to 100%. Patients with MIS-C had high prevalence of gastrointestinal (87%), dermatologic/mucocutaneous (73%), and cardiovascular (71%) symptoms. Prevalence of cardiovascular, neurologic, and respiratory system involvement significantly differed by study inclusion criteria. All studies reported elevated C-reactive protein, interleukin-6, and fibrinogen levels for at least 75% of patients in each study.

CONCLUSIONS

This systematic review of MIS-C studies assists with understanding this newly identified syndrome and may be useful in developing a refined, universal case definition of MIS-C.