Abstract: Objective The aim of this study was to investigate the implication of serum free triiodothyronine (FT3) in patients with hepatitis B virus related acute-on-chronic liver failure (HBV-ACLF). Methods 122 patients with HBV-ACLF were admitted in Beijing You'an Hospital between September 2018 and February 2020, and serum FT3 levels were detected. The area under the receiver operating characteristic curve (AUROC) was applied to analyze the efficacy of serum FT3 for predicting the model for end-stage liver disease (MELD) score. Result Serum FT3 levels in 45 patients with HBV-ACLF early stage, in 46 patients with middle stage and in 31 patients with late stage were (2.73±0.57)pmol/L,(2.55±0.49)pmol/L and (2.29±0.42)pmol/L, significantly different among them(P < 0.001); serum FT3 levels in patients with MELD<30, 30≤MELD<40 and MELD≥40 were (2.77±0.14)pmol/L, (2.32±0.13)pmol/L and (2.08±0.09)pmol/L(P < 0.001), suggesting the tends of increased MELD score as serum FT3 levels gradually decreased; the ROC analysis showed that the 1-AUROC of serum FT3 was 0.739(0.686-0.792), while the 1-AUROCs of total serum bilirubin (TSB) levels, of serum creatinine and international normalized ratio (INR) of prothrombin time were [0.748(0.696-0.800), 0.632(0.562-0.702) and 0.933(0.903-0.963), respectively, P<0.001], suggesting that the efficacy of serum FT3 levels was equal to TSB. Conclusion Serum FT3 levels decrease in patients with HBV-ACLF, which might be a new indicator to judge the severity of the disease.

Key words: Acute-on-chronic liver failure, Free triiodothyronine, Model for end-stage liver disease, Prediction