Thyroid Dysfunction as a Mortality Predictor for ICU Patients

Abstract

Background: Patients suffering from critical illness admitted to the Intensive Care Unit (ICU) exhibit alterations in their thyroid hormone levels. These changes correlate with the outcome and mortality of critically ill patients treated in ICUs. Objective: Our study was conducted to determine thyroid dysfunction as a risk predictor for ICU patients. Patients and Methods: This is a prospective observational cross-sectional non-randomized hospital-based study. The study was performed at the Internal Medicine Intensive Care Units and Surgical Intensive Care Unit of Aswan University hospital at the duration between 1-6-2017 to 30-1-2019 for 200 patients. Results: Regarding TSH, 61.8% sensitivity, 37.1% specificity, 61.3% negative predictive value and 37.6% positive predictive value. Regarding the FT3, 63.2% sensitivity, 50.8% specificity, 69.2% negative predictive value and 44.0% positive predictive value. Regarding the FT4, 15.0 was the cut off value with 61.8% sensitivity, 50.0% specificity, 68.1% negative predictive value, and 43.1% positive predictive value. It showed 54.5% Accuracy & the area under the curve (AUC) was 0.601. From results, FT3 is the most sensitive thyroid function in predicting prognosis and mortality of critically ill patients in ICU. The increase in the APACHE II score could significantly predict the increased risk of mortality while a decrease in FT3 and FT4 could significantly increase the risk of mortality. Conclusions: FT3 was the strongest predictor of ICU mortality. Further, the combination of FT3 levels and APACHE-II scores provided for a higher probability for predicting mortality in ICU patients.