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

https://doi.org/10.1016/j.jpedsurg.2006.01.073Get rights and content

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 χ2 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.

Section snippets

Methods

Data were obtained from the Neonatal Intensive Care Units Study (NICUS) data collection for a population-based study from 1992 to 2001 inclusive. The NICUS was set up as a regional audit tool to collect prospective data from the 10 neonatal intensive care units (NICUs) in NSW and the ACT [3]. Four of these units also perform major neonatal surgery [4]. Criteria for inclusion in the NICUS database are admission to a NICU and any of the following: gestation of less than 32 weeks at birth, birth

Results

There were 919,182 births in NSW and the ACT between 1992 and 2001. Table 1 indicates the pregnancy outcome data for infants with CDH. Of 242 infants identified with CDH, 8% underwent termination of pregnancy, 10% were stillborn after 20 weeks' gestation, and 82% were liveborn. The incidence of CDH was 1 in 3800 births.

Most liveborn infants with CDH (70%) were born at term with a normal birth weight and were male (Table 2). Fifty-six infants (28%) had another defect, most commonly cardiac. Most

Discussion

This population-based study from more than 900,000 births has identified a CDH incidence of 1 in 3800 births. We sourced several validated databases that collected audited, prospective, and regional information. This incidence is in keeping with previously published estimates [1], [9], [10].

We had embarked on this study primarily to identify the survival rates of infants with CDH to enable us to compare these findings with international results. Several North American and Canadian single

Conclusions

The incidence of CDH in NSW and the ACT, Australia, is 1 in 3800 births. Liveborn term infants have a 64% survival rate compared with 35% for preterm infants. A low 5-minute Apgar score, prematurity, and developing an air leak are significantly associated with mortality. Twenty-eight percent of liveborn term infants in a NICU did not survive to reach surgical repair. Unfortunately, there will be a group of infants with CDH who have overwhelming pulmonary hypoplasia, pulmonary hypertension, or

Acknowledgments

The authors thank Dr Lee Taylor, NSW Birth Defects Register, and Ms Barbara Bajuk, NICUS Coordinator.

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