Evaluation of Thyroid Function Tests of Patients Before and After the COVID-19 Pandemic in the Development of Autoimmune Thyroiditis

Abstract

Introduction: Coronavirus disease-2019 (COVID-19) is a severe acute respiratory syndrome. While strong immune reactions play a role in the pathogenesis of COVID-19, autoantibodies, which are the distinguishing feature of autoimmune diseases, are also detected in COVID-19 patients. Many autoimmune diseases may develop after COVID-19 infection. We investigated the relationship between COVID-19 infection and thyroid autoimmunity markers and whether a significant change was observed after the virus infection. Method: In our retrospectively planned study, patients who applied to Bezmialem Vakıf University between March 2017 and March 2023 and were tested for anti-thyroid peroxidase (anti-TPO), anti-thyroglobulin (anti-Tg), and thyroid-stimulating immunoglobulin (TSI) for the development of autoimmune thyroiditis were selected as the sample group. Sociodemographic characteristics of the patients, such as age group, gender, and T3, T4, thyroid stimulating hormone (TSH), anti-TPO, anti-Tg, and TSI laboratory findings were included in the study. Results: Seven hundred eighty-eight people were examined. In 2023, the average age of patients was found to be significantly lower compared to 2018 (p=0.010). No significant difference was observed in terms of the gender distribution of patients between 2023 and 2018 (p=0.936). The average free T4 of patients in 2023 was significantly higher than that in 2018 (p<0.001). In terms of TSH averages, no significant difference was observed between 2023 and 2018 (p=0.470). During this period, the rate of autoimmune thyroiditis cases was found to be approximately 5 times higher based on the total number of hospital admissions. Conclusion: The available data suggest that COVID-19 predisposes to autoimmune thyroid disease because of a decreasing age of disease onset. Further studies are needed to elucidate the pathways that may clarify the relationship between severe acute respiratory syndrome-coronavirus-2 and thyroid autoimmunity. Key words: Autoimmune thyroiditis, COVID-19, anti-TPO, anti-Tg, TSH, T4