Incidence and Short-Term Prognosis of Acute-On-Chronic Liver Failure Defined by Japanese Criteria: A Single-Center Retrospective Cohort Study From Urban Japan.

Background and Aim: Acute-on-chronic liver failure (ACLF) carries high short-term mortality, but real-world evidence under the Japanese ACLF criteria remains limited. We assessed incidence, clinical profile, outcomes, and prognostic factors at a tertiary center in urban Japan. Methods: We retrospectively reviewed 363 consecutive hospitalizations of patients with cirrhosis (2014-2022) at a tertiary care center in Japan. ACLF per Japanese criteria was categorized as confirmed (meeting both PT INR/PT activity and bilirubin thresholds) or extended (meeting either biochemical criterion alone). We pre-specified a parsimonious Cox model with age (per 10 years) and MELD-Na (per 5 points); the primary outcome was time to all-cause death within 90 days (administrative censoring at day 90). Results: ACLF occurred in 40/363 (11.0%) patients (confirmed Conclusions: In this Japanese single center cohort, ACLF (per national criteria) was not rare and carried substantial short-term mortality. Age and MELD-Na were dominant prognostic factors, underscoring early trigger control (notably infection, gastrointestinal bleeding, and alcohol cessation) and timely risk stratification in routine care.