300 Recurrent Wheezing in Third Year Among Children Born at 32 Weeks Gestation: Relationship Respiratory Syncytial Virus During First Year

Abstract

Background: Respiratory syncytial virus (RSV) is responsible for 50-80% of bronchiolitis hospitalizations and the leading cause of hospitalization in children < 1 year. Objective: To quantify the relationship between recurrent wheezing (RW) in year three and documented RSV infection, prematurity, and neonatal oxygen exposure. Design/methods: Participants were 71,102 children born at ≥ 32 weeks gestational age (GA)who were members of an integrated health care delivery system in Northern California for 9 months in their first and third years. The principal exposures were laboratory-confirmed, medically-attended RSV infection during year one, and receipt of supplemental oxygen during birth hospitalization. The outcome was RW in year three. Results: Rate of RW was 16.23% among premature infants with RSV infection and 6.22% among those without. Infants having an RSV outpatient encounter (adjusted odds ratio [AOR] 2.07, 95% CI, 1.61-2.67), uncomplicated hospitalization (AOR 4.66, 95% CI, 3.55-6.12), or prolonged hospitalization (AOR 3.42, 95% CI, 2.01-5.82) were at increased risk for RW compared to infants without RSV infection. GA of 34-36 weeks was associated with increased risk for RW (AOR 1.23, 95% CI 1.071.41) compared to 38-40 weeks, while GA of 41 weeks was protective (AOR 0.90, 95% CI, 0.81-0.99). Supplemental oxygen exposure was associated with increased risk at all levels. The 3 most important predictors were infant sex, family's asthma history, and RSV infection. Conclusions: Laboratory-confirmed, medically-attended RSV infection, prematurity, and exposure to supplemental oxygen during the neonatal period have independent associations with the development of third year RW. The study was sponsored by MedImmune.