Thyroid disease in HCV carriers undergoing antiviral therapy with interferon plus ribavirin

High prevalence of thyroid autoantibodies, with or without overt thyroiditis, has been described in hepatitis C patients, particularly in those undergoing alpha-interferon treatment. The aim of this study was to describe the frequency and clinical outcome of thyroid disease in a cohort of HCV carriers before and during combination therapy with interferon plus ribavirin. Between May, 1997, and May, 1999, 111 previously untreated (naive) patients were treated with a-interferon plus ribavirin for 6 or 12 months. Of those, 67 (60%) patients were male and 44 (40%) female. Thyroid function was evaluated in all patients by testing free T4, TSH and antiTPO within 30 days prior to treatment, 90 days after treatment was initiated, and 6 months after treatment was concluded. Abnormal thyroid tests were observed in 4 (3.6%) patients--1 male and 3 female--before the onset of antiviral treatment. Three patients were already undergoing T4 replacement due to Hashimoto thyroiditis and 1 patient had positive antiTPO with normal free T4 and TSH. All 4 patients completed the treatment regime for HCV, but required hormone replacement. Among the patients with a normal thyroid function test prior to treatment (107 cases), 5 (4.6%) developed thyroid test abnormalities; 2 patients had hypothyroidism due to autoimmune thyroiditis; 1 patient became positive for antiTPO antibodies but thyroid function remained normal, and 2 patients had subacute thyroiditis. Four of these patients (80%) were female and 1 was male (20%). A family history of thyroid disease was strongly predictive of thyroid abnormalities during antiviral treatment. In conclusion, there is a low prevalence of thyroid function abnormalities in HCV carriers with no prior antiviral treatment. Family history of thyroid disease reinforces the special attention to thyroid abnormality development before considering antiviral therapy. Subacute thyroiditis during combination therapy was observed, but its pathogenesis is still unknown. Evaluation of thyroid function during and after antiviral treatment is strongly recommended because thyroid related symptoms can be easily misinterpreted as medication side effects.