The Relationship between FT3 Level and Severity of HBV-ACLF

We aimed to explore the relationship between free triiodothyronine (FT3) level and severity of hepatitis B virus-related acute-on-chronic liver failure (HBV-ACLF). A total of 122 patients with HBV-ACLF who were hospitalized in Beijing You'an Hospital Affiliated to Capital Medical University from September 2018 to February 2020 were included in this study. The FT3 level and the number of organs involved in patients with different stages of liver failure were analyzed. The patients were divided into four groups, Q1, Q2, Q3, and Q4, according to FT3 level. Correlation analysis was used to compare the correlation between FT3 level and Model for End-Stage Liver Disease (MELD) score, chronic liver failure-sequential organ failure assessment (CLIF-SOFA) score, CLIF-consortium organ failure (CLIF-COF) score, and Asian Pacific Association for the Study of the Liver (APASL) acute-on-chronic liver failure (ACLF) Research Consortium (AARC) score. Multiple linear regression, logistic regression and receiver operating characteristic (ROC) curve were used to analyze the effect of FT3 on MELD score. The FT3 level was the lowest in patients with advanced HBV-ACLF, but the highest in patients with early-stage HBV-ACLF (P < 0.01). The more organs involved, the lower the level of FT3 (P < 0.01). The MELD score of Q4 group was the lowest, whereas that of Q1 group was the highest (P < 0.01). Pearson correlation coefficients of FT3 with MELD score, CLIF-SOFA score, CLIF-COF score and AARC score were -0.477, -0.359, -0.347, and -0.391, respectively (P < 0.001). Multiple linear regression analysis showed that the partial regression coefficients of FT3, natural log total bilirubin in milligrams per decaliter {ln[TBIL (mg/dL)]}, natural log creatinine in milligrams per decaliter {ln[CR (mg/dL)]}, and natural log international normalized ratio {ln[INR]} were -0.215, 0.346, 0.231, and 0.667, respectively (P < 0.001). The odds ratio (OR) values of FT3, ln[TBIL (mg/dL)], ln[CR (mg/dL)], and ln[INR] were 0.141 (0.082-0.244), 5.426 (2.697-9.059), 4.535 (2.432-8.455), and 8.642 (6.679-10.267) in the MELD ≥ 30 group compared with MELD < 30 group (P < 0.001). Furthermore, their area under the ROC curve (AUROC) values were 0.739 (0.686-0.792), 0.748 (0.696-0.800), 0.632 (0.562-0.702), and 0.933 (0.903-0.963), respectively (P < 0.001). FT3 level is correlated with the severity of HBV-ACLF, which may be one of the factors to judge the severity of this disease.