Combination effect of ribavirin and erythropoietin treatment on hemoglobin A1c in a diabetic patient with chronic hepatitis C.

Any condition that shortens erythrocyte lifespan or decreases mean erythrocyte age may falsely lower hemoglobin A1c (A1C) test results. Ribavirin (RBV) used for chronic hepatitis C virus (HCV) infection can cause reversible hemolytic anemia; erythropoietin (EPO) used for treatment-related anemia can stimulate the production of red blood cells. We reported a 55-year-old woman with diabetes who received peginterferon alfa plus RBV for HCV infection. Four weeks following HCV therapy, her Hb level declined from 13.3 g/dL to 11.3 g/dL with elevated lactate dehydrogenase and reduced haptoglobin, which confirmed hemolysis. As her Hb fell to a nadir of 8.5 g/dL at the eighth week, darbepoetin alfa was administered to treat anemia consecutively for 10 weeks. Two months later, the patient's A1C declined from 7.5% to an extremely low value of 4.0%, accompanied by a fasting glucose level of 116 mg/dL. During the preceding 3 months, there was no self-reported hypoglycemia or documented low blood glucose. About 3 months after HCV therapy was terminated, the A1C returned to 6.1% without medication adjustment. The concurrent use of RBV and EPO treatments can synergistically cause falsely low A1C values and may lead to inappropriate relaxation of glycemic control. During HCV treatment with RBV, A1C should not be used alone to guide diabetes therapy.