Serious Early Childhood Wheezing Following Respiratory Syncytial Virus Lower Respiratory Tract Infection During Infancy Among Preterm Infants

Friday, October 16, 2009
145 (Washington Convention Center)
Jose R. Romero, MD, Pediatric Infectious Diseases, University of Arkansas for Medical Sciences, Little Rock, AR, Dan L. Stewart, MD, University of Louisville Hospital, Louisville, KY, Erin Buysman, MS, i3 Innovus, Eden Prairie, MN, Ancilla W. Fernandes, PhD, Health Outcomes and Pharmacoeconomics, MedImmune LLC, Gaithersburg, MD, Hasan S. Jafri, MD, Clinical Development, MedImmune, Gaithersburg, MD and Parthiv J. Mahadevia, MD, MPH, Health Outcomes and Pharmacoeconomics, MedImmune, Gaithersburg, MD

Purpose: Respiratory syncytial virus (RSV) lower respiratory tract infection (LRI) in infancy has been associated with bronchial hyperreactivity in the form of wheezing persisting into early childhood. Historically, bronchial hyperreactivity has been defined as recurrent or frequent wheezing. We examined the hypothesis that early infancy RSV LRI in preterm infants is associated with serious early childhood wheezing (SECW) between ages 2 and 3, a novel endpoint developed to capture clinically significant expressions of bronchial hyperreactivity inclusive of recurrent wheezing based on healthcare resource use.


Methods: This is a retrospective cohort study of propensity-matched premature infants ≤36 weeks gestational age born May 1, 2001, through April 30, 2004, comparing children who experienced RSV LRI to those without RSV LRI (controls) in a national US health plan. SECW was defined as 3 visits for asthma/wheezing, or 1 visit for asthma/wheezing + systemic steroid use, or hospitalization for asthma/wheezing, or ≥150 total days of asthma controller therapy. A comparison of the incidence of SECW between the two groups between ages 2 to 3 was made using multivariate logistic regression to adjust for residual differences. Annual healthcare costs were compared for infants with and without SECW.

Results: A total of 378 preterm infants with RSV LRI were matched to 606 controls. The incidence of SECW between ages 2 and 3 was 16.7% in the RSV LRI group vs 8.6% in the control group (P<0.001). After adjusting for confounders, infants with early RSV LRI were more than twice as likely (OR: 2.52, 95% CI: 1.65–3.85) to have SECW compared with controls. Between ages 2 and 3 the overall annual healthcare costs of infants with SECW ($7138 [CI: $5087–$9189]) were higher than infants without SECW ($2407 [CI:$1,63–$3152]; P<0.001).

 Conclusion: The development of RSV LRI during early infancy among preterm infants was associated with a significantly increased rate of SECW between ages 2 and 3. As expected, the associated healthcare costs were significantly higher among SECW patients than patients without SECW. Future studies are needed to confirm these findings.


This study was sponsored by MedImmune.