A population-based study of congenital diaphragmatic hernia outcome in New South Wales and the Australian Capital Territory, Australia, 1992-2001

Abstract

Purpose The aim of the study was to describe the incidence and survival of infants born with congenital diaphragmatic hernia (CDH) in the state of New South Wales (NSW) and the Australian Capital Territory (ACT), Australia. Methods A population-based cohort study of all infants inclusive up to 1 month of age diagnosed with CDH in NSW and the ACT between 1992 and 2001 was conducted. Data sources were the NSW and ACT Neonatal Intensive Care Data Collection (Neonatal Intensive Care Units Study), NSW Birth Defects Register, Population Health Research Centre of ACT Health, and NSW Midwives Data Collection. Individual risk factors for mortality were assessed using the χ 2 test with P < .05 being considered statistically significant. Multivariate analysis was performed using logistic regression to adjust for potential confounding variables. Results From the databases used, the incidence of CDH in NSW and the ACT was 1 per 3800 births. Of 242 infants identified with CDH, 8% underwent termination of pregnancy, 10% were stillborn after 20 weeks' gestation, and 82% were liveborn. Most liveborn infants (70%) were delivered at term with a 64% survival, whereas 30% were preterm with a 35% survival. For liveborn infants, the overall preoperative mortality was 35% with 56% surviving to discharge. Logistic regression identified a low 5-minute Apgar score, prematurity, and air leak as independent risk factors for mortality. Conclusions This population-based study of CDH provides us with baseline data for our states. Mortality is high in preterm infants and in the preoperative period. Avoiding preterm delivery and improving preoperative stabilization are the measures most likely to improve survival.