A Comparison of Alternative Risk-Assessment Strategies for Predicting Significant Neonatal Hyperbilirubinemia in Term and Near-Term Infants

OBJECTIVE: The purpose of this work was to compare the predictive accuracy of alternative risk-assessment strategies used to screen for the risk of significant neonatal hyperbilirubinemia. PATIENTS AND METHODS: We conducted a prospective cohort study of 823 term and near-term newborns admitted to the well-infant nursery at the Hospital of the University of Pennsylvania. Maternal, infant, and delivery risk factors for significant hyperbilirubinemia were obtained from chart review, structured interviews with parents, and nurse assessments before discharge. Transcutaneous bilirubin measurement was performed daily until discharge and once by a visiting home nurse between 3 and 8 days of life. We used the c statistic to compare the predictive accuracy of 3 risk-assessment strategies for estimating the risk of significant neonatal hyperbilirubinemia, defined as a bilirubin level that at any time after birth exceeded or was within 1 mg/dL (17 micromol/L) of the hour-specific phototherapy treatment threshold recommended by the American Academy of Pediatrics in 2004. The compared strategies included those that use (1) a predischarge bilirubin level (obtained before 52 hours) expressed as a risk zone on an hour-specific bilirubin nomogram, (2) clinical risk factors other than the predischarge bilirubin level, and (3) a combination of the predischarge bilirubin risk zone and additional clinical risk factors. RESULTS: Forty-eight patients (6%) developed significant neonatal hyperbilirubinemia. The predischarge (<52 hours) bilirubin level expressed as a risk zone on the bilirubin nomogram and a prediction model that combined multiple other clinical risk factors had similar accuracy for predicting significant hyperbilirubinemia. The only clinical risk factor that could be added to the predischarge risk zone to improve overall predictive accuracy was gestational age. The predischarge bilirubin risk zone and gestational age could be used to stratify patients into a large group (n = 523 70%) of infants with a very low (0.2%) risk of developing significant hyperbilirubinemia, a small group of infants (n = 127 17%) with a low (4%) risk of developing significant hyperbilirubinemia, and an even smaller group of infants (n = 100 13%) with a high (42%) risk of developing significant hyperbilirubinemia. CONCLUSIONS: An infant's risk of developing significant hyperbilirubinemia can be simply and accurately assessed by using just the infant's predischarge bilirubin level and gestational age.