Interrelation Midst Low T3 Levels, Type 3 Deiodinase, Oxidative Stress And Mortality In Sepsis and Septic Shock: Defining Patient Outcome

Background: Low T3 syndrome occurs frequently in patients with sepsis. Type 3 deiodinase (Dio3) is present in immune cells but there is no description of its presence in this patients. Here we aimed to determine the prognostic impact of thyroid hormones levels (TH) measured on ICU admission on mortality and on evolution to chronic critical illness (CCI) and the presence of D3 in white cells. Methods: Prospective cohort study with a follow-up for 28 days or deceased. Results: Low T3 levels at admission were present in 86.5% of the patients. Dio3 was 55% induced in immune cells. The cut-off value of 60 pg/mL for T3 displayed a sensitivity and specificity of 81% and 64% for predicting death, odds ratio of 4.89. Lower T3 yielded an area under the receiver operating characteristic curve of 0.76 and 0.75 for mortality and evolution to CCI, respectively, thus displaying better performance than commonly used prognostic scores. Conclusions: We advance in the pathophysiology of low T3 showing induced D3 in immune cells during sepsis. Low T3 levels independently predicted a progression to CCI and mortality within 28 days in sepsis and septic shock.