Endocrine Abstracts

Alterations in thyroid hormone levels are commonly observed in critical illness with thyroxine replacement remaining a controversial issue. We undertook a prospective observational cohort study in medical intensive care unit of Gauhati Medical College to evaluate whether thyroid hormone levels at admission could be used to predict mortality and compared it to the well established APACHE II scoring system for ICU patients. Serum T₃, T₄ and TSH were estimated at admission in 100 consecutive adults without prior history of thyroid disease admitted to the medical ICU. An APACHE II score was calculated for each patient on the day of admission. The patients were followed up and were divided subsequently into survivors and non-survivors. The TSH, T₄, T₃ and APACHE II scores were compared in both groups. Non-survivor group had 46 patients while survivor group had 54 patients. TSH and T₃ levels in the non-survivor group (0.505±0.515 mIU/l and 0.684±0.10 nmol/l respectively) were significantly lower than that in the survivor group (1.149±1.08 mIU/l and 0.934±0.223 nmol/l) respectively. Total T₄ in non-survivor group (65.32±40.84 nmol/l) was also lower than that in the survivor group (75.56+34.0 nmol/l) but this difference was not statistically significant (P=0.18). There was a statistically significant inverse correlation between APACHE II score and total T₃ and TSH. ROC curve analysis was done for comparing the prognostic value of different parameters. AUC for APACHE II, T₃, TSH and T₄ were 0.96, 0.85, 0.74 and 0.59 respectively.

TSH and total T₃ at admission has prognostic value in patients admitted to the medical intensive care units. Low TSH and T₃ correlates with APACHE II score in predicting poorer outcome.

Declaration of interest: The authors declare that there is no conflict of interest that could be perceived as prejudicing the impartiality of the research project.

Funding: This research did not receive any specific grant from any funding agency in the public, commercial or not-for-profit sector.