Introduction: Asthma exacerbation has been shown to have seasonal variation with the highest rates observed in the months of September. This has been shown to be most prominent in children and coincides with return to school. The goal of our study is to confirm whether the September effect exists in pediatric populations in Nationwide Inpatient Sample (NIS) and whether it translates into the adult population.
Methods: A retrospective analysis of the Healthcare Cost and Utilization Project (HCUP) 2022 NIS was performed. Patients with asthma exacerbation were identified with the ICD-10 codes: J45.21, J45.22, J45.31, J45.32, J45.41, J45.42, J45.51, J45.52, J45.901, J45.902. Sample weighting was employed to produce national estimates. We compared monthly admission frequencies between adults (≥18 years) and children ( < 18 years). Multivariable logistic regression to assess the association between September admissions and patient demographics (sex, insurance), Charlson comorbidity index, and hospital characteristics, stratified by age group.
Results: A total of 127,185 weighted hospitalizations for asthma exacerbation were reported in 2022. Children demonstrated a pronounced spike in admissions in September (10,585 admissions, mean=5404) compared to other months, while adults showed no significant increase (5,205 admissions, mean=5194). After adjusting for covariates, the odds of a pediatric asthma hospitalization occurring in September was 0.21 (95% CI 0.079–0.561, p = 0.002), confirming a strong September spike in children. The odds for adults for admission in September was 0.088 (95% CI 0.065–0.119, p < 0.001), confirming that this is primarily a pediatric phenomenon. Adults had approximately 53% lower odds of September admissions compared to children (OR 0.466, 95% CI 0.432–0.502, p < 0.001).
Conclusions: The September spike in asthma hospitalizations remains predominantly a pediatric phenomenon, even after adjusting for demographics, comorbidities, and hospital characteristics.
