Serious early childhood wheezing after respiratory syncytial virus lower respiratory tract illness in preterm infants

Background: Respiratory syncytial virus (RSV) lower respiratory tract infection (LRI) in early life has been associated with sustained airway hyperreactivity during childhood; however, corresponding data in premature infants are sparse.

Objective: The objective of this study was to determine whether RSV-LRI during early infancy of preterm infants was associated with an increased risk for serious early childhood wheezing (SECW) by age 3 years.

Methods: A retrospective cohort study was conducted using data from a large (∼14 million members) US health plan database. The study population included infants ≤ 6 months of age born at ≤ 36 weeks' gestational age or weighing <2500 g, or both. Preterm infants with any medically attended RSV-LRI from May 2001 through April 2004 with 3 years of continuous eligibility were selected and propensity matched with ≤ 3 control infants. SECW was defined as >3 office, outpatient, or emergency department (ED) visits with asthma or wheezing; ≥ 1 office, outpatient, or ED visit with asthma or wheezing plus treatment with systemic corticosteroids within 7 days; ≥ 1 inpatient stay with asthma or wheezing; or ≥ 150 days' supply of asthma-control medications. The presence of SECW between ages 2 and 3 years was compared between infants with and without RSV-LRI using univariate and multivariate methods. Health care costs for patients with SECW were explored.

Results: A total of 378 infants with RSV were matched to 606 controls. The prevalence of SECW between ages 2 and 3 years was 16.7% in the RSV-LRI group versus 8.6% in the control group (P < 0.001). Logistic regression showed that preterm infants with RSV in early life were 2.52-fold (95% CI,1.65-3.85) more likely to present with SECW between ages 2 and 3 years (P < 0.001). Patients with SECW had a mean SECW-related cost of US $1378 (95% CI, $939-$1816) and total health care cost of $7138 (95% CI, $5087-$9189) compared with $37 (95% CI, $24-$51) and $2521 (95% CI, $1789-$3253), respectively, for patients without SECW. After adjusting for possible confounders, patients with SECW had a significantly higher total health care cost than did patients without evidence of SECW (P < 0.001).

Conclusions: The development of RSV-LRI in infancy in preterm infants was associated with an increased prevalence of SECW between ages 2 and 3 years. Patients with SECW had higher total health care costs than those who did not have SECW.