Assessment of Thyroid Function Tests in Patients with COVID-19 Infection and Their Relationship with Euthyroid Sick Syndrome

Abstract

Aim: Thyroid functions are affected by many factors functions such as some infections and drugs. This study aimed to investigate how the thyroid function tests were affected after COVID-19 infection and their relationship with euthyroid sick syndrome.Material and Method: Our study was designed as a retrospective and case-control study. The participants consisted of two groups as the control and patient groups. Thyroid function tests (TFT), hemogram and routine biochemistry of the groups were assessed. In addition, the tests of the patient group within the last 6 months before the infection were assessed. The patients’ symptoms, presence of a chronic disease, smoking history, and clinical status during COVID-19 infection were recorded.Results: A total of 473 people were included in the study. Of the participants, 54.5% were female. The white blood count (WBC), hemoglobin (HGB), platelet (PLT), and neutrophil (NEU) counts were higher in the patient group. Lymphocyte (LY) and mean platelet volume (MPV) counts were similar. Tyroid stimulating hormone (TSH) and triiodothyronine (T3) values of the patients were higher compared with the control group. The thyroxine (T4) level was similar in the two groups.TSH, T3 and T4 levels of the patient group before COVID-19 were higher than the results just after the quarantine process after COVID-19 infection.Conclusion: Thyroid dysfunction develops in COVID-19 patients within the course of the disease. This condition can be partially explained with the euthyroid sick syndrome. It is also possible with the thyroid gland being the direct or indirect target of the virus.