Discordance Between Japanese and European Definitions of Acute‐on‐Chronic Liver Failure in Alcohol‐Related Cirrhosis: Insights From a 10‐Year Consecutive Cohort

AIM: To examine concordance between the Japanese acute-on-chronic liver failure (ACLF) classification and the organ failure (OF)-based European association for the study of the liver-chronic liver failure (EASL-CLIF) framework, and to clarify the medium-term prognostic implications of discordance in alcohol-related cirrhosis. METHODS: Adults with alcohol-related cirrhosis were studied in a single-center consecutive cohort. Japanese-defined ACLF episodes were classified as confirmed (bilirubin plus coagulation criteria) or extended (either criterion alone), then cross-classified by EASL-CLIF grade. First ACLF episodes were analyzed for 1-year mortality using Kaplan-Meier, Cox, and receiver operating characteristic (ROC) analyses. RESULTS: Among 158 patients, 26 developed Japanese-defined ACLF (30 episodes). Discordance was substantial: 66.7% of extended and 22.2% of confirmed episodes were EASL-CLIF grade 0, not meeting EASL-CLIF criteria. In the first-episode cohort (n = 26), 1-year survival was 77.8% for confirmed and 69.5% for extended ACLF (log-rank p = 0.692). Among Japanese-defined ACLF episodes classified as EASL-CLIF grade 0, the estimated 90-day mortality was 0%, whereas the estimated 1-year mortality was 21.4%. In exploratory ROC analyses, the model for end-stage liver disease (MELD) showed the numerically highest area under the ROC curve for 1-year mortality (AUC 0.797, 95% confidence interval [CI] 0.627-0.967); however, pairwise AUC differences were not significant. CONCLUSIONS: Japanese-defined ACLF, particularly extended ACLF, often corresponds to EASL-CLIF grade 0, yet discordant patients showed non-negligible 1-year mortality. These findings suggest that acute hepatic deterioration without overt OF may represent a clinically relevant early-risk phase in alcohol-related cirrhosis. Hepatic- and OF-based frameworks should therefore be interpreted as complementary.