Thyroid Dysfunction in Relation to Immune Profile, Disease Status, and Outcome in 191 Patients with COVID-19.

OBJECTIVE: Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2)-related thyroiditis is increasingly recognized. The role of thyroid autoimmunity and SARS-CoV-2 viral load in SARS-CoV-2-related thyroid dysfunction is unclear. We evaluated the thyroid function of a cohort of coronavirus disease 2019 (COVID-19) patients, in relation to their clinical features, and biochemical, immunological, and inflammatory markers. METHODS: Consecutive adult patients, without known thyroid disorders, admitted to Queen Mary Hospital for COVID-19 from July 21 to August 21, 2020, were included. Serum levels of thyroid-stimulating hormone (TSH), free thyroxine, free triiodothyronine (fT3), and antithyroid antibodies were measured on admission. RESULTS: Among 191 patients with COVID-19 (mean age 53.5 ±â€…17.2 years; 51.8% male), 84.3% were mild, 12.6% were moderate, and 3.1% were severe. Abnormal thyroid function was seen in 13.1%. Ten patients had isolated low TSH, suggestive of subclinical thyrotoxicosis due to thyroiditis, although the contribution of autoimmunity was likely in 2 of them. Autoimmune thyroiditis probably also contributed to subclinical hypothyroidism in another patient. Ten patients had isolated low fT3, likely representing nonthyroidal illness syndrome. Lower SARS-Cov-2 polymerase chain reaction cycle threshold values and elevated C-reactive protein were independently associated with occurrence of low TSH (P = .030) and low fT3 (P = .007), respectively. A decreasing trend of fT3 with increasing COVID-19 severity (P = .032) was found. Patients with low fT3 had more adverse COVID-19-related outcomes. CONCLUSION: Around 15% of patients with mild to moderate COVID-19 had thyroid dysfunction. There may be a direct effect of SARS-CoV-2 on thyroid function, potentially leading to exacerbation of pre-existing autoimmune thyroid disease. Low fT3, associated with systemic inflammation, may have a prognostic significance.

Thyrotoxicosis in patients with COVID-19: the THYRCOV study.

OBJECTIVE: This study assessed thyroid function in patients affected by the coronavirus disease-19 (COVID-19), based on the hypothesis that the cytokine storm associated with COVID-19 may influence thyroid function and/or the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) may directly act on thyroid cells, such as previously demonstrated for SARS-CoV-1 infection. DESIGN AND METHODS: This single-center study was retrospective and consisted in evaluating thyroid function tests and serum interleukin-6 (IL-6) values in 287 consecutive patients (193 males, median age: 66 years, range: 27-92) hospitalized for COVID-19 in non-intensive care units. RESULTS: Fifty-eight patients (20.2%) were found with thyrotoxicosis (overt in 31 cases), 15 (5.2%) with hypothyroidism (overt in only 2 cases), and 214 (74.6%) with normal thyroid function. Serum thyrotropin (TSH) values were inversely correlated with age of patients (rho -0.27; P < 0.001) and IL-6 (rho -0.41; P < 0.001). In the multivariate analysis, thyrotoxicosis resulted to be significantly associated with higher IL-6 (odds ratio: 3.25, 95% confidence interval: 1.97-5.36; P < 0.001), whereas the association with age of patients was lost (P = 0.09). CONCLUSIONS: This study provides first evidence that COVID-19 may be associated with high risk of thyrotoxicosis in relationship with systemic immune activation induced by the SARS-CoV-2 infection.