High incidence of type 1 diabetes mellitus during or shortly after treatment with pegylated interferon α for chronic hepatitis C virus infection

Background: Development of diabetes mellitus (DM) during or shortly after treatment with interferon α (IFN‐α) in patients with chronic hepatitis C virus (HCV) infection has been reported sporadically. We prospectively screened for DM during and after IFN‐α therapy for chronic HCV infection. Methods: Blood glucose levels of patients with chronic HCV infection were routinely assessed at all outpatient visits during and after treatment with pegylated‐IFN‐α (Peg‐IFN‐α) and ribavirin (Riba). Results: Between December 2002 and October 2005, 189 non‐diabetic patients were treated with Peg‐IFN‐α/Riba, of whom five developed type 1 DM (2.6%), three type 2 DM (1.6%) and one an indeterminate type of DM. Classical symptoms of DM were present in three patients who developed DM shortly after cessation of Peg‐IFN‐α/Riba. In the other patients, symptoms of DM were either indistinguishable from side effects caused by Peg‐IFN‐α/Riba or absent. Conclusion: Our study showed a high incidence of type 1 DM during Peg‐IFN‐α/Riba therapy for chronic HCV infection. Symptoms of DM may be absent or mistaken for Peg‐IFN‐α/Riba‐associated side effects. To diagnose DM without delay, we propose routine assessment of blood glucose at all outpatient visits during and after Peg‐IFN‐α/Riba treatment in chronic HCV patients.