Endocrine Abstracts

Introduction: Non-thyroidal illness syndrome or low T₃ syndrome is an alteration of thyroid hormone levels which occurs as a reaction to acute disease. It is characterized by low TSH levels and low T₃ and T₄ levels. It is transient. The severity of its expression may be related to the severity of the acute disease. It affects patients hospitalized for acute disease in the department of medicine or surgery and in the acute care unit.

Aim: The aim was to study the expression of non-thyroidal illness syndrome and its relationship to survival in the department of medicine in a general hospital in a cohort of patients hospitalized for an acute disease.

Methods: In patients hospitalized for an acute disease after admission to the department of medicine in a general hospital the levels of TSH, T₄, T₃, freeT₄ and freeT₃ were measured over a period of a calendar year. The patients were followed up until exit from the hospital or death. In the department of medicine 831 patients were admitted with acute disease during the period of a calendar year.

Results: Within this group of 831 patients, 230 patients were found to have non-thyroidal illness or low T₃ syndrome. TSH levels were lower in the group of patients with non-thyroidal illness syndrome as opposed to those who did not express the syndrome, 0.52 ± 0.17 µIU/mlas opposed to 2.81 ± 0.34 µIU/ml (P < 0.001, Student’s t test).T₃ levels were lower in the group of patients with non-thyroidal illness syndrome as opposed to those without the syndrome, 0.52 ± 0.049 ng/ml as opposed to 0.57 ± 0.036 ng/ml (P < 0.001). T₄ levels were lower in those with the syndrome as opposed to those without the syndrome, 4.72 ± 0.77 µg/dl as opposed to 6.53 ± 0.43µg/dl (P < 0.001).FT₄ levels were 1.058 ± 0.18 ng/dl in the patients with non-thyroidal illness syndrome as opposed to 1.01 ± 0.15 ng/dl in those without it. The probability of death was found to be higher in the group with the non-thyroidal illness or low T₃ syndrome (chi-square test with Yates correction 7.7593, P = 0.005344).

Conclusion: It appears that the non-thyroidal illness or low T3 syndrome is frequently observed in patients in the department of medicine, who are hospitalized for acute disease of varying etiology. In the cohort described herein the expression of non-thyroidal illness syndrome was found to be related to increased probability of death.