Asthmalitis? Diagnostic Variability of Asthma and Bronchiolitis in Children <24 Months

Bronchiolitis and asthma have similar acute clinical presentations in young children yet have opposing treatment recommendations. We aimed to assess the role of age and other factors in the diagnosis of bronchiolitis and asthma in children <24 months of age.We conducted a retrospective cross-sectional analysis of the Pediatric Health Information System database. We included children aged <2 years diagnosed with bronchiolitis, asthma, wheeze, or bronchospasm in emergency department or hospital encounters from 2017 to 2021. We described variation by age and between institutions. We used mixed-effects models to assess factors associated with a non-bronchiolitis diagnosis in children 12 to 23 months of age.We included 554 158 encounters from 42 hospitals. Bronchiolitis made up 98% of encounters for children <3 months of age, whereas asthma diagnoses increased with age and were included in 44% of encounters at 23 months of age. Diagnosis patterns varied widely between hospitals. In children 12 to 23 months of age, the odds of a non-bronchiolitis diagnosis increased with month of age (odds ratio [OR] 1.13, 95% confidence interval [CI] 1.12–1.13), male sex (OR 1.37, 95% CI 1.35–1.40), non-Hispanic Black race (OR 1.54, 95% CI 1.50–1.58), number of previous encounters (OR 2.73, 95% CI 2.61–2.86, for 3 or more encounters), and previous albuterol use (OR 2.24, 95% CI 2.16–2.32).Non-bronchiolitis diagnoses and the use of inhaled bronchodilators and systemic steroids for acute wheezing respiratory illness increase with month of age in children aged 0 to 23 months. Better definitions of clinical phenotypes of bronchiolitis and asthma would allow for more appropriate treatment in acute care settings, particularly in children 12 to 23 months of age.