Abstract: Objective To explore the value of total tetraiodothyronine(TT4) combined with D-dimer and uric acid in predicting the 28-d prognosis in the elderly patients with septic shock. Methods A retrospective study was conducted to collect the clinical data of the elderly patients with septic shock. According to the 28-d prognosis, all patients were divided into survival group(46 cases) and death group(32 cases). Multivariate Logistic regression was used to analyze the risk factors of prognosis. A prediction model was established, and the discrimination and calibration of the model were calculated; Receiver operator characteristic(ROC) curve was used to assess the predictive value of the prediction model and the Sequential Organ Failure Assessment(SOFA) score. Results Logistic regression showed TT4, D-dimer and uric acid were the independent risk factors of the 28-d prognosis in the elderly patients with septic shock(P<0.05) and a predictive model was established: Y=-3.811-0.553×TT4+0.289×D-dimer+0.013×uric acid. ROC curve showed that the sensitivity and specificity of the predictive model was 91.67%, 94.12%, respectively, with discrimination of 0.961, calibration curve r²=0.991(P=0.887). The area under the ROC curve (AUC) of the model for predicting the prognosis was 0.961(95%CI: 0.889-0.991), which was higher than that of SOFA score (AUC=0.833,95%CI: 0.706-0.959)(P<0.05). Conclusions TT4-related prediction model has a good predictive value for the 28-d prognosis in the elderly patients with septic shock.

Key words: total thyroxine, aged, septic shock, prognosis