Thyroid dysfunction during interferon alpha therapy for chronic hepatitis B and C - twenty years of experience.

Objective: To determine the incidence of thyroid dysfunction in patients with chronic hepatitis B and C (HBV, HCV) who were treated with interferon (IFN) alpha. Patients and methods: In the years 1992-2013, parameters of the thyroid gland were evaluated in 304 patients (256 with HCV, 48 with HBV) who were treated with conventional or pegylated IFN at the Department of Infectious Diseases in Ostrava. Prior to, during and after completion of antiviral treatment, levels of thyroid stimulating hormone (TSH), thyroxine (T4), triiodothyronine (T3), including their free fractions fT4 and fT3, and anti-thyroid antibodies (anti-thyroglobulin, anti-microsomal fraction) were determined and clinical manifestations of thyroid dysfunction were evaluated. Results: TSH changes were detected in 75 patients (25 %), of whom 68 had HCV and 7 HBV. Hypothyroidism was detected in 39 patients (34 with HCV), of whom 25 required substitute therapy which was subsequently terminated in 5 patients. Hyperthyroidism with transient suppressive therapy with carbimazole developed in 4 HCV patients. In 32 patients, TSH changes were assessed as subclinical hypothyroidism. Abnormal T3 values were found in 188 (62 %) and T4 in 49 (16 %) patients; these changes practically did not correlate with TSH changes. Autoantibodies were detected in 54 (18 %) patients of whom 30 were also found to have changes in TSH. Conclusions: In a group of 304 patients treated with IFN alpha for chronic hepatitis, thyroid disease with changes in TSH were observed in a quarter of patients; hypothyroidism clearly prevailed. Thyroid diseases developed in half of the patients with the presence of antithyroid antantibodies.