Characteristics of Subacute Thyroiditis during COVID-19 Pandemic

ABSTRACT

Aim/Introduction: Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), which is causing coronavirus disease (COVID-19), enters host cells via the angiotensin-converting enzyme 2 receptor. Its expression is higher in thyroid gland than in lungs. In the literature, an association between SARS-CoV-2 infection and subacute thyroiditis has been implicated. Therefore, we aimed to explore the influence of COVID-19 pandemic on the incidence and severity of subacute thyroiditis. Material(s) and Method(s) In our retrospective study we reviewed medical records of all patients who were referred for the first time to our thyroid department from 1 April 2019 to 31 May 2019 (before COVID-19) and from 1 April 2020 to 31 May 2020 (during COVID-19). Our institution has a stable catchment area of 1,000,000 inhabitants. Therefore, number of new cases may be considered the incidence of the disease. In each patient who was referred under suspicion of subacute thyroiditis, thyroid specialists performed clinical examination and thyroid ultrasound. In selected cases, thyroid scintigraphy was performed. Serum levels of free thyroxine (normal range 0.59-4.23 pmol/L) and free triiodothyronine (normal range 11.7-22.5 pmol/L) as well as sedimentation rate were measured. Result(s) In the two months period before COVID-19, we examined 946 patients (224 men/722 women) with the mean age 52.0>19.0 years, and in the two months period during COVID-19, we examined 576 patients (154 men/422 women) with the mean age 53.7>18.3 years. Between the two periods, patients did not differ with respect to sex and age (p=0.201 and p=0.438, respectively). Before COVID-19, we found 8 patients with subacute thyroiditis (0.8% from all in that period), while during COVID-19, we found 10 patients with COVID-19 (1.7% from all in that period). The incidence of subacute thyroiditis did not differ significantly between the two periods (p=0.189). Before COVID-19, patients with subacute thyroiditis had similar level of free thyroxine than during COVID-19 (median, range, 36.0 (7.2-70.4) pmol/L and 34.8 (14.7-70.4) pmol/L, respectively, p=0.929). Before COVID-19, the level of free triiodothyronine was similar than during COVID-19 (median, range, 10.9 (2.6-29.4) pmol/L and 9.5 (4.3-21.7) pmol/L, respectively, p=0.929). Before COVID-9, the sedimentation rate was similar than during COVID-19 (median, range, 65 (5-120) mm/h, and 57 (5-113) mm/h, respectively, p=0.916). Conclusion(s) Although we found absolutely and relatively more patients with subacute thyroiditis during COVID-19 than before, the results were not statistically significant. The same applies to the severity of the disease. A longer observation period would probably yield different results.