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

<jats:sec> <jats:title>BACKGROUND</jats:title> <jats:p>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.</jats:p> </jats:sec> <jats:sec> <jats:title>METHODS</jats:title> <jats:p>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.</jats:p> </jats:sec> <jats:sec> <jats:title>RESULTS</jats:title> <jats:p>Forty-three percent of children received HFNC. Asthma was subsequently diagnosed in 37% of HFNC-treated children and 22% of non-HFNC children (P &lt; .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 &lt; .001). No dose-response pattern was observed by HFNC duration or frequency.</jats:p> </jats:sec> <jats:sec> <jats:title>CONCLUSION</jats:title> <jats:p>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.</jats:p> </jats:sec>