ABSTRACT
Background and Aim: CoViD-19 has different clinical manifestations. The aim of this cross-sectional study was to assess thyroid function in CoViD-19 hospitalised patients in relation to the severity of disease. Methods: We assessed 174 CoViD-19 patients hospitalised between March to December 2020 in a High Care Internal Medicine Unit with serum TSH concentration at admission. We excluded those with history of thyroid disease or treated with drugs modifying thyroid function. We evaluated baseline TSH, fT3, fT4 and the severity of disease using PaO2/FiO2, respiratory rate, blood oxygen saturation, type of respiratory support and inflammatory markers. Results: 20% of patients had low TSH (<0.422 mUI/L), 9.9% had thyroiditis (TSH<0.28 mIU/L and/or fT4>17 ng/L). fT3 was assessed in 53 patients and 60% had low fT3 (<2.0 ng/L). Moreover, lower fT3 values were related to higher mortality (p=0.03), hypoalbuminemia (p<0.01) and higher D-dimer (p<0.01). Lower baseline serum TSH concentrations were related to lymphocytopenia (p<0.01) and hypoalbuminemia (p=0.01), and associated with greater need of respiratory support during hospitalisation: the median values were 1.41, 1.38, 1.20 and 0.65 mIU/L in patients who did not need any support, those with only oxygen support, non-invasive ventilation and invasive ventilation respectively (p=0.02). Conclusions: Moderate-to-critical CoViD-19 patients can develop thyroid dysfunctions related to several biomarkers of disease. Baseline serum TSH seems to be related to the severity of respiratory failure developed during hospitalisation.