Clinical Outcomes and Validation of Ursodeoxycholic Acid Response Scores in Patients with Korean Primary Biliary Cholangitis: A Multicenter Cohort Study

BACKGROUND/AIMS: The ursodeoxycholic acid (UDCA) response score (URS) was developed to identify poor responders to UDCA before treatment, in order to offer timely and proactive intervention. However, validation of the URS in Asian population is warranted. METHODS: A total of 173 Asian patients diagnosed with primary biliary cholangitis (PBC) between 2007 and 2016 at seven academic institutions in Korea who started UDCA treatment were analyzed to validate the performance of URS. UDCA response was defined as an alkaline phosphatase level less than 1.67 times the upper limit of normal after 1-year of UDCA treatment. In addition, prognostic performance of URS for liver-related events, defined as newly developed hepatic decompensation or hepatocellular carcinoma was evaluated. RESULTS: After 1 year of UDCA treatment, 133 patients (76.9%) achieved UDCA response. UDCA response rate was 98.7% for those with URS ≥1.41 (n=76) and 58.8% for those with URS <1.41 (n=97). The area under the receiver operating characteristic curve of URS in predicting UDCA response was 0.84 (95% confidence interval, 0.78 to 0.88). During a median follow-up of 6.5 years, liver-related events developed in 18 patients (10.4%). Among 117 patients with PBC stage I-III by histological evaluation, the 5-year liver-related event-free survival rate differed according to the URS; 100% for URS ≥1.41 and 86.5% for URS <1.41 (p=0.005). CONCLUSIONS: URS demonstrated good performance in predicting a UDCA treatment response in Asian PBC patients. In addition, the risk of liver-related events differed according to the URS for the PBC stage. Thus, URS can be used to predict the response and clinical outcome in patients with PBC. (Gut Liver, Published online March 31, 2023)