Background: In a 2004 guideline, the American Academy of Pediatrics (AAP) recommended that every newborn be evaluated for the risk of developing severe hyperbilirubinemia before discharge using total serum bilirubin (TSB) or transcutaneous bilirubin (TcB) levels, or by clinical risk assessment. It is unclear what effect universal screening has had on the rates of severe hyperbilirubinemia and phototherapy use. The Northern California Kaiser Permanente Medical Care Program (NC-KPMCP) instituted universal screening with TSB or TcB levels in 11 hospitals starting in September 2005. Kuzniewicz and colleagues studied the impact of universal screening on the incidence of severe hyperbilirubinemia, defined as TSB levels above the AAP level for exchange transfusion.
The Study: The historical cohort design was used to compare severe hyperbilirubinemia and phototherapy rates before and after universal screening. All live-born infants born between January 1, 1995, and June 30, 2007, at the NC-KPMCP hospitals at 35 weeks of gestation or later and weighing at least 2,000 g (4 lb, 7 oz) were included in the analysis. The authors reviewed all TSB measurements from each infant's first month of life, excluding any in which direct bilirubin accounted for 20 percent or more of the total. Direct Coombs tests were also recorded if performed, and hospitalizations for phototherapy were recorded. TcB readings of 15 mg per dL (256.56 μmol per L) or more (or if the TcB level plus 3 mg per dL [51.31 μmol per L] was above the phototherapy treatment line) were confirmed with a follow-up TSB measurement, per hospital policy.
In 1998, NC-KPMCP refined its newborn management to include a follow-up visit within 48 hours of discharge. Each TSB value was plotted against 2004 AAP treatment curves for phototherapy and exchange transfusion, and infants were risk-stratified based on gestational age and direct antiglobulin test results. Missed phototherapy was defined as any TSB values above the levels at which the AAP recommends phototherapy for a given risk group and time point but that did not result in phototherapy. Phototherapy performed when no TSB values exceeded the AAP cutoff values was defined as subthreshold phototherapy. Characteristics of babies born before and after implementation of universal screening were compared.
Results: The cohort included 319,904 infants; 38,182 were born after universal screening was implemented. The two groups were similar except that the post-implementation group included a higher proportion of Asian infants and more infants in the AAP medium-risk group. The mean number of bilirubin tests increased notably from 0.8 ± 1.7 tests per infant to 1.9 ± 2.0 after implementation. Overall, the mean length of birth hospitalization increased by 2.2 hours after implementation, although among infants receiving phototherapy, the mean length of stay decreased by 28.5 hours. As the proportion of infants undergoing TSB measurements increased during the study, the proportion with a TSB level of 25 mg per dL (427.60 μmol per L) or higher decreased, although the incidence of maximum TSB levels between 15 and 19.9 mg per dL (256.56 and 340.37 μmol per L) increased. There was a 62 percent reduction of TSB values above the exchange guideline, from 0.45 percent before to 0.17 percent after universal screening was implemented. The use of subthreshold phototherapy increased dramatically after 2003, but leveled off with the implementation of universal screening. After 2005, the proportion of infants receiving appropriate phototherapy increased.
Conclusion: The authors conclude that implementing universal screening decreases the incidence of severe hyperbilirubinemia, and results in increased phototherapy rates, often at TSB levels lower than recommended previously by the AAP.