Correlation between dynamic changes in free triiodothyronine levels and 90-day prognosis in patients with HBV-related acute-on-chronic liver failure

Background Patients with HBV-related acute-on-chronic liver failure (HBV-ACLF) have a high 90-day mortality rate, so early prognostic evaluation is important. Aim We aimed to explore the correlation between dynamic changes in free triiodothyronine (FT3) levels and 90-day prognosis of patients with HBV-ACLF. Methods A prospective cohort study investigated 122 inpatients with HBV-ACLF. Patients were divided into three groups based on the dynamic change in FT3 level, as follows: continuous normal FT3; continuous decreased FT3; and FT3 U-shaped change groups, and patients were divided into survival group and non-survival group according to whether they were alive or not. The correlation between the change in FT3 level and 90-day prognosis was explored. Three factors that affected the prognosis most significantly were used to form an FT3 correlation formula to compare the difference in predicting prognosis between the formula score and the conventional score. Results There were 98 patients with decreased FT3 level (80.33%), and the lowest FT3 level was at 8.52 +/- 6.38 days after admission, which lasted for 16 days. There were no significant differences in FT3 levels at admission and at the lowest point between the survival and non-survival groups. Cox regression analysis showed that the FT3 level, FT3 change type, and hepatic encephalopathy (HE) grading were important factors related to prognosis. The area under the receiver operating characteristics curve for the FT3 correlation formula score was 0.892, which was significantly higher than that of the CTP, MELD, MELD-Na, CLIF-SOFA, CLIF-C OF, and AARC scores (P < 0.001). Conclusions The FT3 level and its dynamic change type together with the HE grading can facilitate prediction of 90-day prognosis for patients with HBV-ACLF.