Testing a new screening approach for early diagnosis of biliary atresia
Researchers have found that a two-step newborn screening approach measuring bilirubin levels could identify those with biliary atresia—progress toward a goal of more successfully treating babies earlier in the course of disease. Biliary atresia is a rare and serious progressive liver disease diagnosed in infancy that leads to a back-up of bile into the liver. The disease must be treated with a surgery to restore bile drainage called hepatoportoenterostomy or HPE (also referred to as the Kasai procedure) or a liver transplant. Children who undergo HPE before 30 days of age have the best chance of delaying or preventing the need for a liver transplant, but HPE often occurs after that window because biliary atresia is difficult to detect in its early stages. Thus, an important research goal is to identify ways to diagnose biliary atresia soon after birth to facilitate early treatment and improve health outcomes.
In new research, scientists used knowledge that infants with biliary atresia have elevated levels of bilirubin (a major component of bile) at birth to design and test a 2-stage screening strategy in over 124,000 newborn girls and boys. In the first stage, they analyzed data on babies’ bilirubin levels in blood measured shortly after birth, which was collected as part of routine newborn tests at the 14 south Texas hospitals where the research was conducted. If the newborns had high bilirubin levels in stage 1, they underwent repeat bilirubin testing at or before their routine 2-week well-child doctor’s visit. Infants who tested positive in stage 2 were referred for additional tests to see if they had biliary atresia. The results showed that the screening approach successfully identified all seven children who were subsequently diagnosed with biliary atresia in the study population. However, it also identified another 112 children who did not have the disease—so-called false positives. Tests on those children showed that a few of them had other conditions that benefitted from early detection and treatment, but about half were not diagnosed with any disease or condition. The researchers also conducted a second, smaller study of 43 infants with biliary atresia to compare clinical outcomes of babies who underwent HPE either before or after the screening strategy was implemented. They found that children in the screening group underwent HPE at a younger age, suggesting that the screening approach may facilitate earlier treatment.
This research demonstrates promising progress toward newborn screening for biliary atresia, but the scientists noted several limitations that would have to be overcome before such a screening approach could be recommended on a national scale. For example, screening only occurred at South Texas hospitals, potentially limiting the applicability of the study’s results to other populations. Also, the outcomes study included a relatively small number of children, so it is unknown if similar results would be observed in a larger study. Additional research could help to address these limitations, as well as to study the cost-effectiveness of implementing a population-wide screening approach, as has been done in other countries, and identify ways to reduce the number of false positives. Such research could accelerate further progress toward longer-term goals of early diagnosis and treatment of biliary atresia to improve the health of children.
Harpavat S, Garcia-Prats JA, Anaya C,…Shneider BL. Diagnostic yield of newborn screening for biliary atresia using direct or conjugated bilirubin measurements. JAMA 323: 1141-1150, 2020.