Thyroid Dysfunction in Patients with Chronic Viral Hepatitis B and C during Alpha Interferon Therapy

Background and Aims: Thyroid dysfunction has been reported in patients with chronic viral hepatitis B and C before and after Alpha Interferon (IFN-α) 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 IFNα therapy and to compare them.

Methods: In this prospective study, many patients with hepatitis B and C who had undergone IFNα 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 Tpo Ab before IFN-α 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-α therapy, mean weight of thyroid gland in both HCV and HBV groups were significantly increased (P<0.005, P<0.001, respectively). There were not any relationships between Tg Ab levels and duration of IFNα therapy.

Conclusions: Patients with HCV are more susceptible to thyroid dysfunction during IFN-α 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-α therapy may be necessary. However, this needs further studies in HBV patients.