Abstract

Background and Aims: Thyroid dysfunction has been reported in patients with chronic viral hepatitis B and C before and after alpha interferon (IFN-alpha) therapy and a high prevalence of anti hepatitis C virus (anti-HCV) antibodies in patients with autoimmune thyroiditis has been shown. The aim of this study was to determine the rate of thyroid dysfunction in hepatitis B virus (HBV) and HCV infected patients during IFN-alpha therapy and to compare them. Methods: In this prospective study, many patients with hepatitis B and C who had undergone IFN-alpha therapy were studied. Eighteen cases of HBV and fifty-eight cases of HCV entered the study. Thyroid weight measurement, thyroid functional test and anti-thyroid antibodies assay were performed when the study initiated and were repeated after two, four and six months. Results: Thyroid dysfunction was not seen in the HBV group. Only 6 (10.3) cases of thyroid dysfunction were seen in HCV group (5 hypothyroidism and 1 thyroiditis). Four cases of them had positive levels of thyroid peroxidase antibody (Tpo Ab) before IFN-alpha therapy. In the HBV group, only 1 (5.5) patient had positive levels of Tpo Ab. However, at the end of the study, 3 (16.7) patients had positive levels of Tpo Ab. In the HCV group, at the beginning of the treatment, 8 (13.8) patients had Tpo Ab; but at the end of study, 14 (24.1) cases became positive. During the IFN-alpha therapy, mean weight of thyroid gland in both HCV and HBV groups were significantly increased (P<0.005 and P<0.001 respectively). There were not any relationships between thyroglobulin (Tg) Ab levels and duration of IFN-alpha therapy. Conclusions: Patients with HCV are more susceptible to thyroid dysfunction during IFN-alpha therapy than patients with HBV. As a result, screening of thyroid gland function and Tpo Ab titers in all patients with HCV before and during IFN-alpha therapy may be necessary. However, this needs further studies in HBV patients.