Intravenous ascorbic acid as an adjuvant therapy for recombinant erythropoietin in hemodialysis patients with hyperferritinemia.

Intravenous ascorbic acid as an adjuvant therapy for recombinant erythropoietin in hemodialysis patients with hyperferritinemia. Background. Inadequate iron mobilization and defective iron utilization may cause recombinant erythropoietin (rEPO) hyporesponsiveness in hemodialysis (HD) patients with iron overload. We have demonstrated that intravenous ascorbic acid (IVAA), but not intravenous iron medication, can effectively circumvent the functional iron-deficient erythropoiesis associated with iron overload in HD patients. However, it is uncertain whether all HD patients with hyperferritinemia will consistently respond to IVAA and which index may indicate functional iron deficiency in the special entity. Therefore, a prospective study was conducted to establish the guidelines for IVAA adjuvant therapy. Methods. Sixty-five HD patients with serum ferritin levels of more than 500 μg/liter were recruited and divided into the control (N = 19) and IVAA (N = 46) groups. IVAA patients with a hematocrit (Hct) of less than 30% received 300 mg of ascorbic acid three times per week for eight weeks. Controls had a Hct of more than 30% and did not receive the adjuvant therapy. Red blood cell and reticulocyte counts, iron metabolism indices, erythrocyte zinc protoporphyrin (E-ZPP), and the concentrations of plasma ascorbate and oxalate were examined before and following the therapy. Results. Thirteen patients (four controls and nine IVAA patients) withdrew by the end of the study. Eighteen patients had a dramatic response to IVAA with a significant increase in their hemoglobin and reticulocyte index and a concomitant 24% reduction in rEPO dose after eight weeks. This paralleled a significant rise in serum iron and transferrin saturation (TS) and a fall in E-ZPP and serum ferritin (baselines vs. 8 weeks, serum iron 68 ± 37 vs. 124 ± 64 μg/dl, TS 27 ± 10 vs. 48 ± 19%, E-ZPP 123 ± 44 vs. 70 ± 13 μmol/mol heme, and serum ferritin 816... [ABSTRACT FROM AUTHOR]