Thyroid dysfunction during treatment of chronic hepatitis C with interferon alpha: no association with either interferon dosage or efficacy of therapy

. Dalgard O, Bjøro K, Hellum K, Myrvang B, Bjøro T, Haug E, Bell H (Aker University Hospital, Oslo; National Hospital, Oslo; Akershus Central Hospital, Nordbyhagen; and Ullevål University Hospital, Oslo, Norway). Thyroid dysfunction during treatment of chronic hepatitis C with interferon alpha: no association with either interferon dosage or efficacy of therapy. J Intern Med 2002; 251: 400–406. Objectives. Treatment of chronic hepatitis C with interferon‐α (IFN‐α) may induce thyroid disorders. We evaluated whether this risk is related to the dosage of IFN‐α or the virological treatment response. Other possible risk factors as well as the evolution of the thyroid abnormalities were also studied. Methods. In this prospective trial (n=254), thyroid‐stimulating hormone (TSH), free thyroxin (fT4) and thyroid peroxidase autoantibodies were measured before, during and after treatment for hepatitis C virus (HCV). The patients were randomized to either induction therapy [IFN‐α 6 million units (MIU) daily for 4 weeks and 3 MIU 3/7 days for 22 weeks] or conventional therapy [IFN‐α 3 MIU 3/7 days for 26 weeks]. In addition, all patients received ribavirin (1000 or 1200 mg) daily. Sustained virological response was defined as loss of detectable HCV RNA at 6 months follow‐up. Thyroid dysfunction was defined as TSH level below or above the normal range (0.2–4.5 MIU L−1). Results. Biochemical thyroid dysfunction developed in 30 (11.8%) of 254 patients. Hypothyroidism (TSH > 4.5 MIU L−1) was seen in 20 and hyperthyroidism (TSH