Characteristics and Disease Severity of US Children and Adolescents Diagnosed With COVID-19

1In 2020, more than 2 000 000 pediatric COVID-19 cases were reported in the United States. Although approximately half of pediatric patients with COVID-19 experience mild disease, some children require admission to intensive care units or use of invasive mechanical ventilation. We conducted a cohort study to estimate adjusted associations between demographic and clinical characteristics and severe COVID-19 among hospitalized pediatric patients.

2Discharge data from 869 medical facilities that contributed inpatient and emergency department encounters to the Premier Healthcare Database Special COVID-19 Release (PHD-SR) (release date, December 9, 2020), an administrative all-payer database capturing approximately 20% of US hospitalizations, were used to describe patients 18 years or younger who had an inpatient or emergency department encounter with a primary or secondary COVID-19 discharge diagnosis from March 1 through October 31, 2020. The International Statistical Classification of Diseases, Tenth Revision, Clinical Modification (ICD-10-CM) diagnosis code U07.1 was used from April 1 through October 31, 2020, and code B97.29 was used from March 1 through April 30, 2020. The discharge data were also used to estimate associations between demographic and clinical characteristics and severe COVID-19 among pediatric patients hospitalized with COVID-19. This study was reviewed by the Centers for Disease Control and Prevention and was deemed exempt from institutional review board oversight per 45 CFR §46.101(b)(4) and exempt from patient informed consent based on 45 CFR §164.506(d)(2)(ii)(B) because the disclosed PHD-SR data are considered deidentified. This study followed the Strengthening the Reporting of Observational Studies in Epidemiology (STROBE) reporting guideline.

3Severe COVID-19 was defined as care requiring treatment in an intensive care unit or step-down unit, involving use of invasive mechanical ventilation, or resulting in death. We used the Agency for Healthcare Research and Quality Chronic Condition Indicator tool to identify chronic conditions using ICD-10-CM diagnoses from January 1, 2019, up to and including the child’s initial COVID-19 encounter. Race/ethnicity was defined by information in patient medical records in the PHD-SR.

4Adjusted odds ratios (AORs) and 95% CIs for severe COVID-19 were calculated using a multivariable generalized estimating equations model adjusting for within-facility correlation, age, sex, race/ethnicity, insurance type, and presence of chronic conditions. Statistical analysis was performed using SAS version 9.4 (SAS Institute Inc). The a priori significance level was set at P =.05; all hypothesis testing was 2-sided.

5Among 20 714 pediatric patients with COVID-19, 10 950 (52.9%) were girls, 11 153 (53.8%) were aged 12 to 18 years, 8148 (39.3%) were Hispanic or Latino individuals, 5054 (24.4%) were non-Hispanic Black individuals. Among these patients with COVID-19, 6047 (29.2%) had 1 or more chronic conditions (Table).

6Among the cohort of 2430 pediatric patients (11.7%) who were hospitalized with COVID-19, 756 (31.1%) experienced severe COVID-19. An increased association of severe COVID-19 was observed among patients with 1 or more chronic conditions vs those with none (AOR, 3.27; 95% CI, 2.44-4.37); in children aged 2 through 5 years or 6 through 11 years vs those aged 12 through 18 years (AORs, 1.53; 95% CI, 1.11-2.13 and 1.53; 95% CI, 1.04-2.23, respectively); and in male vs female patients (AOR, 1.52; 95% CI, 1.26-1.83) (Figure). There was no statistically significant association between race/ethnicity or insurance type and severe COVID-19.

7In this cohort study, nearly one-third (756 [31.1%]) of hospitalized pediatric patients with COVID-19 experienced severe COVID-19, which is consistent with previous findings. Our analysis revealed an increased association of severe COVID-19 in younger children (those aged 2-11 years) compared with older children (those aged 12-18 years). Although admission to an intensive care unit for younger children may indicate an abundance of caution by clinicians or facility and administrative requirements rather than disease severity, this finding has important clinical and resource planning implications for facilities and clinicians.

8Our results suggest that existing chronic conditions and male sex are independently associated with severe COVID-19. Consistent with previous reports, non-Hispanic Black and Hispanic or Latino children with COVID-19 were overrepresented compared with all pediatric patients in the PHD-SR. We found no statistically significant association between severe disease and race/ethnicity among hospitalized patients when controlling for covariates.

9This study has some limitations. First, risk factors associated with severe disease from acute COVID-19 vs multisystem inflammatory syndrome in children cannot be differentiated, as the latter condition does not have its own ICD-10-CM diagnosis code. Second, chronic conditions could be underlying, co-occurring, or sequelae of COVID-19 illness. Third, certain chronic conditions might be underdiagnosed in inpatient medical records. Fourth, we were unable to evaluate associations among infants younger than 12 months.

10Although most children with COVID-19 experience mild illness, some children develop serious illness that leads to hospitalization, use of invasive mechanical ventilation, and death. Understanding factors associated with severe COVID-19 disease among children could help inform prevention and control strategies. Reducing infection risk through community mitigation strategies is critical for protecting children from COVID-19 and preventing poor outcomes.