Abstract: Objective To investigate the changes of implication of serum diamine oxidase（DAO） level in patients with hepatitis B-induced acute-on-chronic liver failure（ACLF）. Methods A total of 104 patients with ACLF were admitted to our hospital between August 2014 and April 2017,and 64 patients survived and 40 died in 60 day observation. Serum DAO levels were detected by ELISA,and the factors affecting the prognosis of patients were analyzed by Logistic regression analysis. Results Serum DAO level in the survival group was （15.1±4.8） ng/mL,significantly lower than（68.4±25.4） ng/mL （P<0.05） in the fatal group;univariate analysis showed that serum TBIL,AST,ALT,INR,ALB,Cr,and MEID score,WBC,spontaneous bacterial peritonitis,hepatic encephalopathy,ascites,as well as cirrhosis were associated with the bad prognosis,and multivariate regression analysis demonstrated that high MELD scores,high DAO levels and patients’ age were the independent risk factors for death of patient with ACLF;the survival rates in patients with serum DAO≥48.7 ng/mL and with serum DAO<48.7 ng/mL were 50.0% and 77.3% （x2=7.977,P=0.005）,the survival rates in patients with MELD≥26.1 and with MELD<26.1 were 45.5% and 79.6%,and the survival rates in patients greater than 40-yr-old and under 40 were 50.8% and 79.5%,respectively （all P<0.05）. Conclusion Serum DAO levels might be used as a new parameter for predicting the prognosis of patients with ACLF,which needs further investigation.

Key words: Acute-on-chronic liver failure, Hepatitis B, Diamine oxidase, Prognosis