Post-bronchiolitis Use of Asthma Medication: A Prospective 1-year Follow-up Study.
BACKGROUND
Our aim was to evaluate the association between viral findings during bronchiolitis and the use of asthma controller medication (primary outcome) and systemic corticosteroids (secondary outcome) during the first post-bronchiolitis year.


METHODS
We enrolled 408 children hospitalized for bronchiolitis at <24 months of age in a prospective, 3-center, 1-year follow-up study in Finland. Viruses were detected with polymerase chain reaction in nasopharyngeal aspirates. The parents underwent a structured interview during hospitalization. Twelve months later, the use of asthma medication was asked in a structured questionnaire. Multivariable logistic regression was used for statistical analysis.


RESULTS
In total, 365 (89%) children completed the 1-year follow-up. The use of long-term asthma controller medication was highest in the rhinovirus-positive group (61% vs. 15% in respiratory syncytial virus-positive group; adjusted odd ratios, 7.5; 95% confidence interval: 3.7-15.3), followed by children negative for both respiratory syncytial virus and rhinovirus (36%; adjusted odd ratios, 2.6; 95% confidence interval: 1.3-5.3). Likewise, rhinovirus etiology was associated with more courses of systemic corticosteroids during the follow-up. The main findings were similar in a subset of infants aged <12 months with first wheezing.


CONCLUSIONS
Children hospitalized for rhinovirus-positive bronchiolitis used long-term asthma controller medication more often than those hospitalized for rhinovirus-negative bronchiolitis during first year after hospitalization.