Abstract
BACKGROUND: To date, 11 cases of COVID-19-associated newly diagnosed Hashimoto's thyroiditis (HT) have been reported. To investigate the clinical characteristics and influencing factors of Corona Virus Disease 2019 (COVID-19) complicated by newly diagnosed Hashimoto's thyroiditis (HT) and to inform clinical management. METHOD: A total of 369 COVID-19 patients were enrolled and divided into three groups: Negative for Antibodies (NA group, n=288), HT group (n=54), and Thyroid Autoimmune (TA group, n=27). The clinical characteristics and influencing factors of the HT group were analyzed. Data analysis was performed using SPSS 27.0 statistical software. RESULTS: Patients in the HT group were older than those in the NA group [72.5 (63.5, 79.0) vs. 69 (58.3, 76.0) years, P = 0.031]. Fatigue was significantly more common in the HT group compared to both the TA group and the NA group (53.7% vs. 22.2%, and 53.7% vs. 24.0%, all P<0.001). The incidence rates of subclinical hyperthyroidism and hypothyroidism in the HT group were significantly higher than in the NA group (29.6% vs. 13.9%, P = 0.020; 7.4% vs. 1.7%, P = 0.017). Multivariate analysis identified prolonged viral clearance time (OR = 1.136) as an independent risk factor for COVID-19 complicated by HT. Advanced age (OR = 0.944) and low FT3 (OR = 4.233) were identified as independent risk factors for increased mortality risk in COVID-19 patients. CONCLUSION: COVID-19 patients complicated by HT are typically older, with fatigue being a distinguishing clinical manifestation. They are more prone to thyroid dysfunction, with subclinical hyperthyroidism being the predominant early thyroid function abnormality. Prolonged viral clearance time was identified as a factor associated with newly diagnosed HT.