Predicting death or major neurodevelopmental disability in extremely preterm infants born in Australia

Abstract

Background: The aim of this study was to determine if the National Institute of Child Health and Human Development (NICHD) calculator, designed to predict mortality or neurosensory disability in infants 22-25 weeks' gestation, was valid for contemporary Australian infants.

Method: Outcome data at 2 years of age for 114 infants who were liveborn in Victoria, Australia, in 2005, between 22 and 25 completed weeks' gestation, weighing 401-1000 g at birth, and free of lethal anomalies, were entered into the NICHD online calculator. Predicted outcomes were then compared with the actual outcomes.

Results: Of the 114 infants, 99 (87%) were inborn and 15 (13%) were outborn. The overall prediction of death for inborn infants was 47.1% compared with the actual death rate to 2 years of age of 49.5%. The area under the curve (AUC) was 0.803 (95% CI 0.718 to 0.888; p<0.001) for mortality, comparable with the AUC for the NICHD study (AUC: 0.753; 95% CI 0.737 to 0.769; p<0.001). The accuracy for predicting death was not as precise for outborn infants (AUC: 0.643; 95% CI 0.337 to 0.949; p=0.36). The calculator overestimated the combined outcome of death or survival with major disability at 72.0%, compared with an actual rate of 60.5%.

Conclusions: The NICHD outcome estimator was helpful in predicting mortality for inborn infants, 22-25 weeks' gestation, but was less precise for outborn infants. It overestimated the combined outcome of death or major disability in infants born in Victoria, Australia, in 2005.