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 n = 10, extended n = 30). Frequent precipitants were infection, gastrointestinal bleeding, and alcohol use, often in combination. The 90‐day mortality by Kaplan–Meier was 30.5%. Age (per 10 years) was associated with higher 90‐day mortality (HR, 2.29; 95% CI 1.31–4.00; p < 0.01), as was Model for End‐Stage Liver Disease including sodium (MELD‐Na) (per 5 points) (HR, 1.74; 95% CI 1.16–2.63; p < 0.01). 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.