Respiratory Syncytial Virus Bronchiolitis and Risk of Subsequent Wheezing: A Matter of Severity

The objective was to determine the effect of requirement of hospitalization as a measure of disease severity of Respiratory Syncytial Virus (RSV) bronchiolitis on subsequent wheezing. Records were reviewed of all patients younger than 2 years of age with first episode of wheezing presenting to pediatric community-based clinics between 2001 and 2003 who are now at least 1 year older. Only patients who were tested for RSV were included. Multivariable logistic regression was performed to identify variables that were related to the odds of having recurrent wheezing including age, gender, history of smoke exposure, family history of asthma/allergic rhinitis, hospitalization, RSV status, and treatment with steroid. One hundred fifty-five patients were included. Multivariate analysis identified hospitalization, RSV negativity and male gender as independent significant determinants of recurrent wheezing. Twenty-three of the 41 hospitalized patients had recurrent wheezing compared to 52 of 114 of the nonhospitalized patients (p = 0.037). Forty of the 56 RSV-negative patients had recurrent wheezing compared to 35 of the 99 RSV-positive patients (p < 0.001). Fifty-two out of 90 males had recurrent wheezing compared to 23 of 65 females (p < 0.01). There was no significant difference between RSV-positive and RSV-negative patients in regards to the other variables. Recurrent wheezing within 1 year of first episode of bronchiolitis was higher in RSV-negative patients and in patients with illness severe enough to be hospitalized. This supports the notion that bronchiolitis is a heterogeneous airway disease and the severity plays an important role in recurrent wheezing. (Pediatr Asthma Allergy Immunol 2006; 19[1]:26–30.)