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Oxford University Press - PMC COVID-19 Collection logoLink to Oxford University Press - PMC COVID-19 Collection
. 2020 Nov 3:dgaa813. doi: 10.1210/clinem/dgaa813

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

David Tak Wai Lui 1, Chi Ho Lee 1, Wing Sun Chow 1, Alan Chun Hong Lee 1, Anthony Raymond Tam 1, Carol Ho Yi Fong 1, Chun Yiu Law 2, Eunice Ka Hong Leung 1, Kelvin Kai Wang To 3, Kathryn Choon Beng Tan 1, Yu Cho Woo 1, Ching Wan Lam 4, Ivan Fan Ngai Hung 1, Karen Siu Ling Lam 1,
PMCID: PMC7665541  PMID: 33141191

Abstract

Objective

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 COVID-19 patients, in relation to their clinical features, biochemical, immunological and inflammatory markers.

Methods

Consecutive adult patients, without known thyroid disorders, admitted to Queen Mary Hospital for COVID-19 from 21 July to 21 August, 2020 were included. Serum levels of thyroid-stimulating hormone (TSH), free thyroxine, free triiodothyronine (fT3) and anti-thyroid antibodies were measured on admission.

Results

Among 191 patients with COVID-19 (mean age 53.5 ± 17.2 years; 51.8% male), 84.3% were mild, 12.6% were moderate, and 3.1% were severe. 13.1% had abnormal thyroid function. Ten patients had isolated low TSH, suggestive of subclinical thyrotoxicosis due to thyroiditis, although the contribution of autoimmunity was likely in two of them. Autoimmune thyroiditis probably also contributed to subclinical hypothyroidism in another patient. Ten patients had isolated low fT3, likely representing non-thyroidal illness syndrome. Lower SARS-Cov-2 PCR cycle threshold values and elevated C-reactive protein were independently associated with occurrence of low TSH (p=0.030) and low fT3 (p=0.007) respectively. A decreasing trend of fT3 with increasing COVID-19 severity (p=0.032) 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.

Keywords: COVID-19, SARS-CoV-2, thyroid function tests, thyroiditis, euthyroid sick syndromes, thyroid gland


Articles from The Journal of Clinical Endocrinology and Metabolism are provided here courtesy of Oxford University Press

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