Chang YK, et al. - In patients with chronic hepatitis C (CHC) infection in Taiwan, researchers examined the occurrence and risk factors of thyroid dysfunction (TD). Drawing on data from the Taiwan National Health Insurance Research (Taiwan NHIR) database between 2001 and 2013, 3,810 patients and 9,393 controls were included during the study period. Data revealed that the types of TD in these patients were hypothyroidism (42.9%), hyperthyroidism (31.2%), and thyroiditis (25.9%). Among patients with hepatitis C virus (HCV) infection, pegylated interferon/ribavirin (PEG-IFN/RBV) treatment could be an independent risk factor for thyroid dysfunction. Clinicians, particularly with female patients and patients with a history of hyperlipidemia and goiter, are strongly advised to monitor thyroid function during PEG-IFN/RBV therapy in patients with chronic HCV infection.