Recurrent wheezing phenotypes after severe bronchiolitis and progression to asthma

Background: Recurrent wheezing, a common diagnosis after severe bronchiolitis, has multiple phenotypes of uncertain relation to childhood asthma.

Objective: Among infants hospitalized for bronchiolitis, we investigated the relation of three 2020 recurrent wheezing phenotypes by age 4 years to asthma by age 6 years.

Methods: In a 17-center cohort study of infants hospitalized with bronchiolitis, we investigated the National Heart, Lung, and Blood Institute (NHLBI) 2020-defined recurrent wheezing phenotype and 2 additional phenotypes based on this definition: multitrigger and severe. As a sensitivity analysis, we examined the NHLBI 2007 recurrent wheezing phenotype. We calculated the proportion of study subjects who developed asthma by age 6 years and used multivariable logistic regression to examine characteristics associated with the highest-risk 2020 phenotype.

Results: Of 921 infants, 632 (69%) developed NHLBI 2020 recurrent wheezing, 734 (80%) developed multitrigger wheezing, and 165 (18%) developed severe wheezing by age 4 years; in addition, 296 (32%) developed NHLBI 2007-defined recurrent wheezing by age 3 years. Of 862 children with sufficient data (94%), 239 (28%) developed asthma by age 6 years. The proportions of children who progressed to asthma were as follows: 33% of those with NHLBI 2020-defined wheezing, 33% of those with multitrigger wheezing, 54% of those with severe wheezing, and 52% of those with NHLBI 2007-defined recurrent wheezing. The children with the severe phenotype who developed asthma had the associated characteristics preterm birth, child eczema, maternal asthma, and non-respiratory syncytial virus infection.

Conclusion: Most infants with severe bronchiolitis developed the NHLBI 2020-defined recurrent wheezing phenotype by age 4 years. Depending on the phenotype, 33% to 54% will develop asthma by age 6 years. Future research will examine whether earlier treatment of high-risk phenotypes will improve wheezing symptoms and potentially prevent childhood asthma. (J Allergy Clin Immunol Global 2023;2:84-7.).