The External Validation of GLOBE and UK-PBC Risk Scores for Predicting Ursodeoxycholic Acid Treatment Response in a Large US Cohort of Primary Biliary Cholangitis Patients

Background: The cornerstone treatment for primary biliary cholangitis (PBC) is ursodeoxycholic acid (UDCA), but many patients exhibit an incomplete response, leading to disease progression. Risk prediction models like the GLOBE and UK-PBC scores hold promise for patient stratification and management. We aimed to independently assess the predictive accuracy of these risk scores for UDCA response in a prospective U.S. cohort. Methods: We conducted a prospective cohort study at a U.S. liver center, monitoring UDCA-treated PBC patients over a one-year follow-up. We evaluated the predictive efficacy of the GLOBE and UK-PBC scores for UDCA treatment response, comparing them to the Paris II criteria. Efficacy was assessed using univariate and multivariate analyses, followed by prognostic performance evaluation via receiver operating characteristic (ROC) curve analysis. Results: We evaluated 136 PBC patients undergoing UDCA therapy. Based on the Paris II criteria, patients were categorized into UDCA full-response and non-response groups. The GLOBE score identified a non-responder rate of 18% (p = 0.205), compared to 20% (p = 0.014) with the Paris II criteria. Multivariate analysis, adjusted for age and biochemical markers, showed that both the GLOBE and UK-PBC scores were strongly associated with treatment response (p < 0.001). The area under the ROC curve was 0.87 (95% CI 0.83-0.95) for the GLOBE score and 0.94 (95% CI 0.86-0.99) for the UK-PBC risk score. Conclusions: Our study demonstrates that GLOBE and UK-PBC scores effectively predict UDCA treatment response in PBC patients. The early identification of patients at risk of an incomplete response could improve treatment strategies and identify patients who may need second-line therapies.