Thyroid dysfunction is associated with the loss of hepatitis B surface antigen in patients with chronic hepatitis B undergoing treatment with α-interferon

OBJECTIVE: To investigate the influence of thyroid dysfunction on the antiviral efficacy of α-interferon in adult patients with chronic hepatitis B (CHB). METHODS: We performed a retrospective study of 342 patients with CHB who underwent interferon treatment for >12 weeks. Patients with thyroid dysfunction before or during treatment were defined as the thyroid dysfunction group (n = 141) and those with normal thyroid function were defined as the normal thyroid function group (n = 201). The prevalences of hepatitis B virus (HBV) DNA undetectability, low hepatitis B surface antigen (HBsAg) titre (<250 IU/mL), HBsAg loss, and hepatitis B envelope antigen loss were compared. RESULTS: During interferon treatment, 69 of 270 (25.6%) participants with normal thyroid function at baseline developed thyroid dysfunction, whereas 11 of 72 (15.3%) with thyroid dysfunction at baseline regained normal thyroid function. The thyroid dysfunction group had significantly higher prevalences of low HBsAg titre (29.8% vs. 18.9%) and HBV DNA undetectability (66.0% vs. 40.3%). Multivariate logistic regression analysis showed that thyroid dysfunction was associated with HBsAg loss (odds ratio 4.945, 95% confidence interval 1.325–18.462). CONCLUSIONS: These results suggest that thyroid dysfunction is not an absolute contraindication, but is associated with HBsAg loss, in patients with CHB undergoing α-interferon treatment.