Background and AimsCurrently, acute-on-chronic liver failure (ACLF) has been defined differently by Asia–Pacific Association for the Study of the Liver (APASL) and Chinese Medical Association (CMA) in the East, as well as EASL-Chronic Liver Failure (EASL-CLIF) Consortium in the West. This study aimed to compare current different diagnostic criteria for ACLF and to determine predictors of the progression into post-enrollment EASL-CLIF ACLF from ACLF at enrollment defined by APASL alone or by both APASL and CMA but not by EASL-CLIF Consortium.MethodsWe retrospectively analyzed clinical data from 394 eligible cirrhotic patients fulfilling at least APASL criteria for ACLF at enrollment. Patient survival was estimated by Kaplan-Meier analysis and subsequently compared by log-rank test. Independent predictors of disease progression were determined using univariate analysis and multivariate Cox regression analysis.ResultsThe 90-day mortality rate was 13.1% in patients with ACLF at enrollment defined by APASL alone, 25.3% in patients with ACLF at enrollment defined by both APASL and CMA but not EASL-CLIF Consortium, and 59.3% in patients with ACLF at enrollment defined by EASL-CLIF Consortium in addition to APASL. Baseline Chronic Liver Failure-Sequential Organ Failure Assessment (CLIF-SOFA) score, and the maximum rising rates of CLIF-SOFA score, Model for End-Stage Liver Disease-Sodium (MELD-Na) score and total bilirubin were independent predictors of progression into post-enrollment EASL-CLIF ACLF from ACLF at enrollment defined by APASL alone or by both APASL and CMA but not by EASL-CLIF Consortium.ConclusionDifferent diagnostic criteria for ACLF caused different patient prognosis. So, it is imperative to formulate a unifying diagnostic criteria for ACLF worldwide, thus attaining early identification and treatment, and eventual improvement in survival of ACLF patients. Baseline CLIF-SOFA score, and the maximum rising rates of CLIF-SOFA score, MELD-Na score and total bilirubin may early predict post-enrollment development of EASL-CLIF ACLF.