Thyroid profile prognostic value on disease severity and mortality in COVID-19

Abstract

Background: Precise accurate triage of Coronavirus disease 2019 (COVID-19) patients during hospitalization for early identification of individuals at risk of developing severe disease is essential as Intensive Care Units (ICUs) are overwhelmed by the pandemic burden. The aim of this study was to evaluate thyroid function in patients with COVID-19. Methods: 60 healthy controls and 180 patients were admitted to a cardiothoracic hospital, Minia University, Egypt, between March 2020 and September 2021 without a history of thyroid disease. Patients divided as 60 non-COVID pneumonia patients with a similar degree of severity were included as another control group to find any unique effects of COVID-19 on thyroid function, 120 positive COVID-19 divided according to clinical classifications into moderate (n = 58), severe (n = 21), and critical (n = 41), Critical group were admitted to ICU and classified to survivors (n = 33) and non-survivors (n = 8). COVID patients also were divided into tertiles according to their FT3 levels. Lowes tertile (n = 45), middle tertile (n = 37) and highest tertile (n = 38). All participants underwent routine physical checkups, acute physiology, and chronic health evaluation (APACHE-II) scores. The outcome measure was death during hospitalization; intensive care admission, mechanical ventilation, and length of hospitalization. We analyzed the ability of each parameter to predict mortality in participants. Further, we also evaluated whether the combination of free triiodothyronine (FT3) level with APACHE-II score could improve the mortality prediction. Results: Thyroid Stimulating Hormone (TSH) was lower than normal range in 56.7% (68/120) of patients with COVID-19. TSH and serum-free triiodothyronine (FT3) were significantly lower in COVID-19 patients than healthy control and non-COVID-19 pneumonia patients. TSH and FT3 were lower in severe COVID-19 with statistical significance (p < 0.001) and both positively correlated with the severity. The free thyroxine (FT4) in COVID-19 patients was not significantly different from the control group. Patients in the lowest FT3 tertile had significantly higher rates of mortality (18/40), mechanical ventilation (24/53.3), and intensive care unit admission (20/44.4). In univariate analyses, FT3 remained the most significant independent predictor of death. Conclusion: The changes in serum TSH and FT3 levels may be important manifestations of COVID-19 courses.FT3 levels can serve as a prognostic tool for disease severity in early presentation of COVID-19.