Long COVID in Patients With Mild to Moderate Disease: Do Thyroid Function and Autoimmunity Play a Role?

Objective Long COVID (LC) is an emerging global health issue. Fatigue is a common feature. Whether thyroid function and autoimmunity play a role is uncertain. We aimed to evaluate the prevalence and predictors of LC and the potential role of thyroid function and autoimmunity in LC. Methods We included consecutive adults without known thyroid disorder, admitted to a major COVID-19 centre for confirmed COVID-19 from July to December 2020 who had thyroid function tests (TFTs) and anti-thyroid antibodies measured on admission and at follow-up. LC was defined by the presence or persistence of symptoms upon follow-up. Results In total, 204 patients (median age: 55.0 years; 46.6% men) were reassessed at a median of 89 days (IQR: 69–99) after acute COVID-19. Forty-one (20.1%) had LC. Female (adjusted odds ratio [aOR] 2.48, p=0.018) and SARS-CoV-2 PCR cycle threshold value
Long COVID is common among COVID-19 survivors, with female and those with higher viral load in acute COVID-19 particularly vulnerable. Our observation of incident anti-TPO positivity among COVID-19 survivors warrants further follow-up for thyroid dysfunction. Whether anti-TPO plays a protective role in long COVID remains to be elucidated.