Association Between High-Flow Nasal Cannula Use for Bronchiolitis and Subsequent Asthma Diagnosis

BACKGROUND High-flow nasal cannula (HFNC) therapy is widely used in infants hospitalized with moderate-to-severe bronchiolitis. Although bronchiolitis severity has been consistently associated with later asthma, it remains unclear whether HFNC contributes additional risk or instead represents a marker of severe illness. We examined the relationship between HFNC use during bronchiolitis hospitalization and the subsequent hazard of asthma diagnosis in early childhood. METHODS We conducted a retrospective cohort study of 4736 children aged younger than 2 years hospitalized with bronchiolitis from 2015 to 2023 across 2 tertiary children’s hospitals. Children were stratified by HFNC exposure. Cox proportional hazards models evaluated the association between HFNC use and subsequent asthma diagnosis. Secondary analyses assessed HFNC duration and frequency. RESULTS Forty-three percent of children received HFNC. Asthma was subsequently diagnosed in 37% of HFNC-treated children and 22% of non-HFNC children (P < .001). After adjustment for demographic and clinical variables, HFNC use was associated with a 40% increased hazard of subsequent asthma diagnosis (hazard ratio, 1.40; 95% CI, 1.24–1.57; P < .001). No dose-response pattern was observed by HFNC duration or frequency. CONCLUSION HFNC use was associated with an increased hazard of subsequent diagnosis of asthma in childhood, likely reflecting underlying disease severity rather than a treatment-related effect. Prospective studies are needed to differentiate severity-related risk from treatment-associated factors to optimize respiratory support strategies for infants with bronchiolitis.