Persistent recurring wheezing in the fifth year of life after laboratory-confirmed, medically attended respiratory syncytial virus infection in infancy.

BACKGROUND: Respiratory syncytial virus (RSV) infection in infancy is associated with subsequent recurrent wheezing. METHODS: A retrospective cohort study examined children born at ≥32 weeks gestation between 1996-2004. All children were enrolled in an integrated health care delivery system in Northern California and were followed through the fifth year of life. The primary endpoint was recurrent wheezing in the fifth year of life and its association with laboratory-confirmed, medically-attended RSV infection during the first year, prematurity, and supplemental oxygen during birth hospitalization. Other outcomes measured were recurrent wheezing quantified through outpatient visits, inpatient hospital stays, and asthma prescriptions. RESULTS: The study sample included 72,602 children. The rate of recurrent wheezing in the second year was 5.6% and fell to 4.7% by the fifth year. Recurrent wheezing rates varied by risk status: the rate was 12.5% among infants with RSV hospitalization, 8% among infants 32-33 weeks gestation, and 18% in infants with bronchopulmonary dysplasia. In multivariate analyses, increasing severity of respiratory syncytial virus infection was significantly associated with recurrent wheezing in year 5; compared with children without RSV infection in infancy, children who only had an outpatient RSV encounter had an adjusted odds ratio of 1.38 (95% CI,1.03-1.85), while children with a prolonged RSV hospitalization had an adjusted odds ratio of 2.59 (95% CI, 1.49-4.50). CONCLUSIONS: Laboratory-confirmed, medically attended RSV infection, prematurity, and neonatal exposure to supplemental oxygen have independent associations with development of recurrent wheezing in the fifth year of life.

Recurrent wheezing in the third year of life among children born at 32 weeks' gestation or later: relationship to laboratory-confirmed, medically attended infection with respiratory syncytial virus during the first year of life.

OBJECTIVE: To quantify the relationship between recurrent wheezing (RW) in the third year of life and respiratory syncytial virus (RSV) infection, prematurity, and neonatal oxygen exposure. DESIGN: Retrospective cohort study linking inpatient, outpatient, and laboratory databases for cohort assembly and logistic regression analysis. SETTING: Integrated health care delivery system in Northern California. PARTICIPANTS: A total of 71,102 children born from 1996 to 2002 at 32 weeks' gestational age or later who were health plan members for 9 or more months in their first and third years. MAIN EXPOSURES: Laboratory-confirmed, medically attended RSV infection during first year and supplemental oxygen during birth hospitalization. OUTCOME MEASURES: Recurrent wheezing, quantified through outpatient visits, inpatient hospital stays, and asthma prescriptions. RESULTS: The rate of RW in the third year of life was 16.23% among premature infants with RSV and 6.22% among those without RSV. The risk of RW increased among infants who had an RSV outpatient encounter (adjusted odds ratio [AOR], 2.07; 95% CI, 1.61-2.67), uncomplicated RSV hospitalization (AOR, 4.66; 95% CI, 3.55-6.12), or prolonged RSV hospitalization (AOR, 3.42; 95% CI, 2.01-5.82) compared with infants without RSV encounters. Gestational age of 34 to 36 weeks was associated with increased risk of RW (AOR, 1.23; 95% CI 1.07-1.41) compared with 38 to 40 weeks, while a gestational age of 41 weeks or more was protective (AOR, 0.90; 95% CI, 0.81-0.99). Supplemental oxygen exposure was associated with increased risk at all levels. CONCLUSION: Laboratory-confirmed, medically attended RSV infection, prematurity, and exposure to supplemental oxygen during the neonatal period have independent associations with the development of RW in the third year of life.