Serum bile acids as a prognostic biomarker in biliary atresia following Kasai portoenterostomy

Background and Aims: In biliary atresia, serum bilirubin is commonly used to predict outcomes after Kasai portoenterostomy (KP). Infants with persistently high levels invariably need liver transplant, but those achieving normalized levels have a less certain disease course. We hypothesized that serum bile acid levels could help predict outcomes in the latter group. Approach and Results: Participants with biliary atresia from the Childhood Liver Disease Research Network were included if they had normalized bilirubin levels 6 months after KP and stored serum samples from the 6-month post-KP clinic visit (n = 137). Bile acids were measured from the stored serum samples and used to divide participants into ≤40 μmol/L (n = 43) or >40 μmol/L (n = 94) groups. At 2 years of age, the ≤40 μmol/L compared with >40 μmol/L group had significantly lower total bilirubin, aspartate aminotransferase, alanine aminotransferase, gamma-glutamyltransferase, bile acids, and spleen size, as well as significantly higher albumin and platelet counts. Furthermore, during 734 person-years of follow-up, those in the ≤40 μmol/L group were significantly less likely to develop splenomegaly, ascites, gastrointestinal bleeding, or clinically evident portal hypertension. The ≤40 μmol/L group had a 10-year cumulative incidence of liver transplant/death of 8.5% (95% CI: 1.1%-26.1%), compared with 42.9% (95% CI: 28.6%-56.4%) for the >40 μmol/L group (p = 0.001). Conclusions: Serum bile acid levels may be a useful prognostic biomarker for infants achieving normalized bilirubin levels after KP.