Efficacy of a low-dose intravenous iron sucrose regimen in peritoneal dialysis patients

Sufficient iron substitution leads to a decrease in the required recombinant human erythropoietin (rHuEPO) dose and/or an increased hematocrit in dialysis patients. Intravenous (i.v.) application of larger doses of iron sucrose may be associated with hyperferritinemia, appearance of catalytically free iron, and impaired phagocyte function. Therefore, we investigated the effectiveness of a low-dose i.v. iron regimen in peritoneal dialysis (PD) patients. Forty-five PD patients were followed over a period of 1 year. Serum ferritin, serum transferrin saturation, and hemoglobin were measured monthly. In cases of absolute iron deficiency (serum ferritin < 100 microg/L), 50 mg iron sucrose was given i.v. every second week. In cases of functional iron deficiency (ferritin > or = 100 microg/L and transferrin saturation < 20%) and in iron repleted patients (ferritin > or = 100 microg/L and transferrin saturation > or = 20%), 50 mg i.v. iron sucrose was applied monthly. Iron therapy was stopped in cases of acute infection (until complete recovery) and when serum ferritin level was > or = 600 microg/L. To analyze the influence of iron substitution on erythropoiesis and rHuEPO requirements, the EPO resistance index (ERI; quotient of rHuEPO dose in units/kilogram/week and hemoglobin in grams per deciliter) was calculated every 3 months. The ERI decreased significantly during the course of the study in the whole patient group (p = 0.009) as well as in the subgroup of 21 patients with absolute iron deficiency (p = 0.01). A nonsignificant decrease in the ERI was observed within the group of 14 iron repleted patients (p = 0.5). There was no significant change in the ERI in 10 patients with functional iron deficiency (p = 0.6). The low-dose i.v. iron regimen used in this study substantially decreased rHuEPO requirements in patients with absolute iron deficiency and was effective in maintaining iron stores in iron repleted patients. However, in the absence of significant hyperparathyroidism, aluminum toxicity, or inadequate dialysis, it did not improve the ERI in patients with functional iron deficiency.