Patent ductus arteriosus, indomethacin and necrotizing enterocolitis in very low birth weight infants: a population-based study.

BACKGROUND Patent ductus arteriosus is a risk factor for the development of necrotizing enterocolitis. The use of indomethacin to treat patent ductus arteriosus in preterm infants may either decrease the incidence of necrotizing enterocolitis by stabilizing or closing the ductus arteriosus or increase its incidence by a direct constricting effect on mesenteric blood vessels. The authors sought to evaluate the interrelationship between patent ductus arteriosus, treatment with indomethacin and the risk of necrotizing enterocolitis in very low birth weight infants. METHOD The Israel National database includes prospectively collected data on 99% of all very low birth weight infants in Israel. The study population comprised 6146 infants of 24-34 weeks' gestation born between 1995 and 2000. The effect of patent ductus arteriosus on necrotizing enterocolitis was assessed using multiple regression analysis. RESULTS Necrotizing enterocolitis occurred in 5.5% (n = 343) of all infants, in 9.4% of infants with patent ductus arteriosus and in 8.9% of infants who received indomethacin. The occurrence of necrotizing enterocolitis was independently associated with the presence of patent ductus arteriosus among infants not treated with indomethacin (odds ratio, 1.85) and those who received indomethacin therapy (odds ratio, 1.53). Indomethacin therapy in absence of patent ductus arteriosus was not associated with an increased risk of necrotizing enterocolitis (odds ratio, 0.72). CONCLUSIONS Patent ductus arteriosus is an independent risk factor for the development of necrotizing enterocolitis in very low birth weight infants. Therapy with indomethacin did not have a significant effect on the risk for necrotizing enterocolitis.