Jaundice impacts more than half of term and late preterm newborns in the first week of life. Although in most cases, jaundice is benign, the consequences of severe hyperbilirubinemia are debilitating; thus, identification of newborns likely to exceed bilirubin treatment thresholds is needed. The American Academy of Pediatrics (AAP) recommends stratification of predischarge total serum bilirubin (TSB) levels by using the Bhutani Nomogram to help determine the appropriate timing of newborn follow-up. A separate nomogram is then used to determine if an infant meets criteria for phototherapy.1
Kuzniewicz et al2 aim to simplify the process and more precisely determine when a newborn requires outpatient follow-up for jaundice with a simple equation. Starting with a retrospective cohort study of a diverse sample of 148 162 newborns born at ≥35 weeks’ gestation at 11 Kaiser Permanente Northern California facilities from 2012 to 2017, the researchers identified newborns whose TSB measurements did not exceed phototherapy levels and did not receive phototherapy during the birth hospitalization. Using the newborn’s last TSB value before hospital discharge (predischarge TSB), the authors calculated the difference between the predischarge total serum bilirubin and the corresponding American Academy of Pediatrics phototherapy threshold (in milligrams/deciliter) (Δ-TSB). Newborns who required phototherapy after discharge were identified. The authors compared the ability of the Δ-TSB model to predict postdischarge TSB above phototherapy thresholds to the Bhutani Nomogram. Examining additional variables, they also compared a more complicated Δ-TSB-Plus model. Although all 3 models performed well for those at highest and lowest risk of subsequent severe hyperbilirubinemia, both Δ-TSB and Δ-TSB-Plus models differentiated newborns in the intermediate zones better than the Bhutani Nomogram. Forty-four percent of newborns in Bhutani’s high-intermediate risk zone (who would have follow-up recommended within 48 hours) had a Δ-TSB between −4 and −5 mg/dL. In these newborns, the risk of ever having a subsequent TSB measurement greater than the AAP threshold was only 1.6%, suggesting follow-up within 48 hours might not be indicated.