Non-Insulin-Dependent Diabetes Mellitus Developing during Interferon-α Therapy for Chronic Hepatitis C

TO THE EDITOR:

Development of non–insulin-dependent (autoimmune) diabetes mellitus has been suggested in patients treated with interferon-α [1-3]. We describe a patient who developed this disease with no evidence of an immune process while receiving interferon-α for hepatitis C.

A 50-year-old man was referred to us because of chronic active hepatitis C. His cousin had insulin-dependent diabetes, but no family member had a history of non–insulin-dependent diabetes. Recombinant interferon-α was started at a dose of 32 million U three times a week. Before therapy, the patient had glucose intolerance. After 1 week of treatment, his fasting plasma blood glucose level was 5.5 mmol/L. After 7 weeks of therapy, the glucose level suddenly increased to 25.6 mmol/L. The patient's hemoglobin A_1c value was 9.5%. The thyroid-stimulating hormone value was in the normal range, and tests for thyroid peroxidase antibodies were negative. Interferon-α therapy was discontinued, and diabetes was controlled after 0.55 U of insulin per kg of body weight per day was given for 1 week. The patient's insulin requirement then decreased quickly, and he stopped taking insulin 3 months after discontinuing interferon-α therapy. His glucose levels were well controlled by diet alone. Results of tests for islet-cell antibodies by immunofluorescence and for insulin autoantibodies by immunoprecipitation were negative before interferon-α therapy and 10 days and 1.5 months after interferon-α therapy was discontinued. Results of tests for glutamic acid decarboxylase antibodies by immunoprecipitation were negative 10 days after cessation of interferon-α therapy. The patient's basal and poststimulation C peptide values were not low before, while, or after insulin therapy was received.