Epidemiology of ICU Admissions for Bronchiolitis in the United States: 2001-2019

Introduction: Among children admitted to US children’s hospitals for bronchiolitis, PICU utilization increased in recent years. However, nationally representative data including all hospital types show decreases in the total number of bronchiolitis admissions and in use of invasive mechanical ventilation (IMV). To reconcile these seemingly conflicting trends, we aimed to provide the first nationally representative descriptions of the epidemiology of critical bronchiolitis in the current era, hypothesizing that national ICU use and costs have increased.


Methods: With IRB approval, we queried an existing dataset from the Healthcare Utilization Project’s state inpatient databases for children < 2 years with a primary or secondary diagnosis of bronchiolitis. Demographics, ICD procedure and diagnosis codes, hospital costs, and outcomes were available for 2001, 2004, 2010, 2016 and 2019. Linear regression (continuous variables; shown as linear coefficient [LC] with 95% CI) and linear Poisson regression (categorical variables; shown as relative risk [RR] with 95% CI) were used to estimate changes since 2001. National estimates are based off US Census data.


Results: Among 23,208 children with critical bronchiolitis in 21 states, 34% were age < 3mo, 41% female, 36% non-Hispanic white, 74% without comorbidity, 74% admitted in children’s hospitals, and 60% publicly insured. The annual number of US children admitted to an ICU with bronchiolitis tripled since 2001 (RR in 2019: 3.4 [3.2-3.6]) to an estimated 40,091 patients nationally in 2019, accounting for 16% of all pediatric ICU admissions. The rate of IMV decreased from 20% to 14% (RR 0.68 [0.60-0.76]), though the absolute number of children receiving IMV increased (RR 2.3 [2.0-2.6]). The prevalence of multiorgan failure increased from 5% to 13% (RR 2.5 [2.0-3.2]). In-hospital mortality decreased from 0.6% to 0.2% [RR 0.34 (0.15-0.79)] and median per-patient costs increased to $10,699 (IQR 6,419-19,706) (LC $5076 [1548–8604]), with a total national estimate of $990,000,000 spent on critical bronchiolitis in 2019.


Conclusions: From 2001-2019, the number of US children admitted to an ICU with critical bronchiolitis grew substantially. Despite the low mortality, increasing prevalence of organ failure and hospital costs suggest opportunity for improved care practices.