Objective: To assess the impact of multiple births and crowded homes on the severity of respiratory syncytial virus illness in preterm infants with bronchopulmonary dysplasia.
Research design: Retrospective case-control chart review from a prospective longitudinal respiratory illness study.
Setting: Neonatal High-Risk Follow-Up Clinic (outpatient setting) and tertiary care hospitals (inpatient setting).
Participants: Fourteen sets of twins and two sets of triplets followed up between 1983 and 1989 and matched with 34 singleton infants for date of birth (within 3 months) and gestational age (within 1 month).
Measurements/main results: The risk of developing respiratory syncytial virus illness was significantly higher in multiple-birth infants than in singletons (53% vs 24%; P = .01). Multiple-birth infants were also at greater risk for developing pneumonia (24% vs 6%; P = .05) and requiring hospitalization (32% vs 18%; P = .05) than were singletons. Additional risk factors for developing pneumonia and bronchiolitis were examined in all 68 children. Multiple birth (P = .05), gestational age of less than 30 weeks (P = .02), and crowded homes (defined as more than one person living in 19 m2 of living space [P = .002] or more than one child living in 22 m2 of living space [P = .004]) were additional risk factors for developing pneumonia.
Conclusion: Multiple-birth preterm infants are at a higher risk of developing pneumonia than are singletons. Additional risk factors for developing pneumonia in preterm infants with bronchopulmonary dysplasia include gestational age of less than 30 weeks and crowded homes. At-risk infants with any of these risk factors should be targeted for prophylactic and therapeutic interventions against respiratory syncytial virus.