The impact of COVID 19 infection on HCV-induced thyroid disease.

Context: As we progress into the COVID-19 pandemic, it has become apparent that this infection is associated with a multitude of systemic effects, some involving the thyroid gland. The thyroid is also frequently affected in the HCV chronic infection. Objective: The objective of this study is to determine the effects of COVID-19 infection on the presence and severity of thyroid disorders associated with chronic HCV infection, at short and mid-term follow-up. Design: We prospectively evaluated patients with documented HCV- associated thyroid disease (with sustained virologic response after antiviral therapy). Subjects and Methods: The study group consisted of 42 patients with HCV- associated thyroid disease, diagnosed with COVID -19 infection between April and October 2020. We determined serum values of thyroid-stimulating hormone, freeT3, free T4, anti-thyroglobulin antibodies and anti-thyroid peroxidase antibodies at one and three months after resolution of infection and compared them to the baseline characteristics of the patient. We also evaluated the changes in thyroid substitution treatments or antithyroid drugs. Results: At baseline, out of the 42 patients, 5 presented hypothyroidism under levothyroxine substitution therapy, while 2 presented hyperthyroidism under methimazole therapy; 37 patients had positive antithyroid antibodies. At one month follow-up, we note an increase in serum values of antibodies, with a decrease in TSH, freeT3 and freeT4 levels, correlated with the severity of COVID-19 infection. Two patients required discontinuation of levothyroxine. At 3 months follow-up, lower levels of antithyroid antibodies were recorded, with an increase in TSH levels. No medication doses were adjusted at this time. Conclusion: Among the systemic effects of COVID-19, the impact of thyroid dysfunction should not be underestimated, especially in the presence of pre-existing conditions, such as HCV infection.