Cazzagon, Nora

Background and Aims: Normal alkaline phosphatase (ALP) levels in ursodeoxycholic acid (UDCA)-treated patients with primary biliary cholangitis (PBC) are associated with better long-term outcome. However, second-line therapies are currently recommended only when ALP levels remain above 1.5 times the upper limit of normal (×ULN) after 12-month UDCA. We assessed whether, in patients considered good responders to UDCA, normal ALP levels were associated with significant survival gains. Approach and Results: We performed a retrospective cohort study of 1047 patients with PBC who attained an adequate response to UDCA according to Paris-2 criteria. Time to liver-related complications, liver transplantation, or death was assessed using adjusted restricted mean survival time (RMST) analysis. The overall incidence rate of events was 17.0 (95% CI: 13.7–21.1) per 1000 out of 4763.2 patient-years. On the whole population, normal serum ALP values (but not normal gamma-glutamyl transpeptidase (GGT), alanine aminotransferase (ALT), or aspartate aminotransferase (AST); or total bilirubin < 0.6 ×ULN) were associated with a significant absolute complication-free survival gain at 10 years (mean 7.6 months, 95% CI: 2.7 - 12.6 mo.; p = 0.003). In subgroup analysis, this association was significant in patients with a liver stiffness measurement ≥ 10 kPa and/or age ≤ 62 years, with a 10-year absolute complication-free survival gain of 52.8 months (95% CI: 45.7–59.9, p < 0.001) when these 2 conditions were met. Conclusions: PBC patients with an adequate response to UDCA and persistent ALP elevation between 1.1 and 1.5 ×ULN, particularly those with advanced fibrosis and/or who are sufficiently young, remain at risk of poor outcome. Further therapeutic efforts should be considered for these patients.

AbstractBackground & AimsMachine learning (ML) provides new approaches for prognostication through the identification of novel subgroups of patients. We explored whether ML could support disease sub‐phenotyping and risk stratification in primary biliary cholangitis (PBC).MethodsML was applied to an international dataset of PBC patients. The dataset was split into a derivation cohort (training set) and a validation cohort (validation set), and key clinical features were analysed. The outcome was a composite of liver‐related death or liver transplantation. ML and standard survival analysis were performed.ResultsThe training set was composed of 11,819 subjects, while the validation set was composed of 1,069 subjects. ML identified four clusters of patients characterized by different phenotypes and long‐term prognosis. Cluster 1 (n = 3566) included patients with excellent prognosis, whereas Cluster 2 (n = 3966) consisted of individuals at worse prognosis differing from Cluster 1 only for albumin levels around the limit of normal. Cluster 3 (n = 2379) included young patients with florid cholestasis and Cluster 4 (n = 1908) comprised advanced cases. Further sub‐analyses on the dynamics of albumin within the normal range revealed that ursodeoxycholic acid‐induced increase of albumin >1.2 x lower limit of normal (LLN) is associated with improved transplant‐free survival.ConclusionsUnsupervised ML identified four novel groups of PBC patients with different phenotypes and prognosis and highlighted subtle variations of albumin within the normal range. Therapy‐induced increase of albumin >1.2 x LLN should be considered a treatment goal.