Rehospitalization for Respiratory Illness in Infants of Less Than 32 Weeks' Gestation

Abstract

All 133 surviving infants of gestational age ≤32 weeks born July 1, 1985, to June 30, 1986, as well as a socioeconomically matched full-term control group were observed prospectively for 2 years to determine the incidence of rehospitalization for respiratory illness. Perinatal and seasonal factors associated with increased risk for such hospitalizations were also examined. Forty-seven (36%) preterm infants were rehospitalized compared with 3(2.5%) of 121 term infants (P<.001). Preterm infants with and without rehospitalization were similar for mean birth weight (1104±329 g and 1188±360 g, respectively) and gestational age (28 ± 2 weeks for both groups); however, infants who were subsequently rehospitalized had required more days of mechanical ventilation, supplemental oxygen therapy, and neonatal intensive care. While a history of bronchopulmonary dysplasia was a risk factor for rehospitalization (45% compared with 25% of those without bronchopulmonary dysplasia, P < .05), preterm infants with no history of bronchopulmonary dysplasia still showed a 10-fold increase compared with control infants. Among the 43 infants who required no mechanical ventilation beyond the day of birth, 10 (23%) required rehospitalization. More than 80% of rehospitalized infants required their first admission within 4 months of discharge from the neonatal intensive care unit. Consequently, initial hospital discharge between September and December (the months immediately preceding peak respiratory viral season) resulted in an almost 3-fold increased risk of rehospitalization compared with discharge between May and August (P<.05). At 6 months of age, infants rehospitalized prior to that time had more than twice the incidence of neurologic abnormalities (12/23 [36%] vs 9/83 [11%], P<.01) than did infants who were never rehospitalized. The former group also had significantly lower motor scores on the Bayley Scales of Infant Development (89 ± 18 vs 97 ± 14, P< .05). These differences were not apparent at 15 and 24 months of age. Respiratory illness contributes significantly to postdischarge morbidity in preterm infants with and without chronic lung disease.