Abstract Background and Aim Hepatitis C virus (HCV) infection causes insulin resistance and diabetes as extrahepatic manifestations. We aimed to analyze the effect of HCV eradication by direct‐acting antiviral (DAA) agents on glucose tolerance. Methods The hemoglobin A1c (HbA1c) of 272 patients with HCV infection who achieved a sustained virologic response (SVR) was analyzed at baseline before DAA treatment, at the end of DAA therapy (ETR), and 12 weeks after therapy (Post12W). Results There were no significant differences in HbA1c between baseline, ETR, and Post12W in the overall patients. When the data were stratified according to the presence or absence of diabetes, median HbA1c significantly decreased from baseline (7.2%) to ETR (6.8%) and Post12W (6.8%) in the 55 patients with diabetes, whereas there were no significant changes in the patients without diabetes. Basal HbA1c, fasting plasma glucose, and age were independently associated with the changes in HbA1c according to multivariate analysis, and the predictive formula for changes in HbA1c was found to be ΔHbA1c (%) = 1.449–0.4* HbA1c (%) + 0.012 × Age (year). There were no changes in body mass in diabetic or nondiabetic patients. In diabetic patients taking medication, 63.4% of patients needed less medication. Conclusions Eradication of HCV improves glycemic control, indicated by a 0.4% decrease in HbA1c in diabetes.
