Resolution of diabetes in type 2 diabetic patient treated with IFN-alpha and ribavirin for hepatitis C

We report on a patient whose type 2 diabetes mellitus resolved during IFN-alpha therapy for hepatitis C virus (HCV). A 40-year-old man was diagnosed with type II diabetes in year 2000. His body mass index (BMI) was 30.8 kg/m and glycosylated haemoglobin (HbA1c) was 10.7%. He was treated with metformin. Later, his glycaemic control deteriorated despite additional dietary and lifestyle advice and the addition of glibenclamide. He was started on subcutaneous insulin in 2002 with the continuation of metformin. In 2003 he was diagnosed with chronic hepatitis caused by HCV. In September 2003 he was started on IFN-alpha and ribavirin. After 24 weeks of treatment his HCV polymerase chain reaction remained positive and treatment was stopped as per guidelines. At the commencement of antiviral therapy, HbA1c was 7.7%. In April 2004 his BMI of 29.38 kg/m had reduced and he then stopped insulin therapy because of repeated hypoglycaemia. After stopping insulin his HbA1c was 4.7%. Fasting plasma glucose of 6.2 mmol/l and anti-glutamic acid decarboxylase antibodies were negative. Urea and creatinine levels were normal. Most of the earlier literature describes diabetes developing in the course of IFN-alpha therapy for a variety of diseases. More recent research has described a relationship between hepatitis C infection and the development of diabetes and insulin resistance. Responders to IFN-alpha treatment manifest an improvement in insulin sensitivity compared with non-responders after the completion of IFN-alpha therapy. Our case shows the resolution of pre-existing diabetes in a patient with chronic HCV infection, which did not respond to IFN-alpha therapy. Whether this occurred as a direct result of IFN-alpha on insulin sensitivity or indirectly as a result of weight loss because the therapy for HCV precipitated additional lifestyle changes in the patient is as yet unclear.