Primary hyperthyroidism induced erythropoietin-resistant anemia?

We describe a 26-year-old male hemodialysis patient with erythropoietin (EPO) resistant anemia associated with primary hyperthyroidism. Use of the anti-hyperthyroid drug, methimazole, led to improvement of his hyperthyroidism and anemia. Before the anti-hyperthyroid therapy, he had received transfusions to maintain an adequate hematocrit during recombinant human EPO therapy. After the therapy, his hyperthyroidism improved and his hematocrit gradually increased without any transfusion. These findings suggest that the patient's EPO resistant anemia was the result of primary hyperthyroidism, and that this complication is reversible if accurate treatment is given.