Controversies in iron management

BACKGROUND: Iron therapy is required in hemodialysis patients receiving erythropoietic stimulators in order to achieve the target hemoglobin in the most efficient way. While oral iron has been disappointing in this regard, parenteral iron has been widely used, despite a significant incidence of severe side effects when iron dextran is used. The recent availability of a more effective form of oral iron (heme-iron), and safer forms of parenteral iron (iron sucrose and iron gluconate) has made iron management in this population simpler. Many questions remain, however, about the use, efficacy, and safety of these compounds in hemodialysis patients. METHODS: Current literature was reviewed and combined with the authors' clinical experience to address a number of current questions regarding the use of iron in hemodialysis patients. RESULTS: Although oral non-heme iron is infrequently sufficient to maintain iron stores in hemodialysis patients, recent studies suggest that heme-iron may be more useful in this regard. Heme-iron is absorbed to a greater extent than non-heme iron, and is better tolerated. Small studies have shown that when heme-iron is administered, less parenteral iron and lower doses of erythropoietin (EPO) are needed to maintain target hemoglobin. Current evidence suggests that both iron sucrose and iron gluconate are safer than iron dextran, and the latter should only be used in extraordinary circumstances. While in vitro studies have demonstrated some differences in the effects of iron sucrose and iron gluconate on cellular toxicity, the clinical importance of these has not been determined. Both compounds can be used safely for repletion and maintenance therapy, and doses of up to 300 mg of either are generally well tolerated when such higher doses are needed, as in peritoneal dialysis (PD) patients or chronic kidney disease (CKD) patients not on dialysis. CONCLUSION: A number of questions remain regarding the appropriate use, efficacy, and potential toxicity of iron therapy in dialysis patients. Further prospective research should address the myriad questions raised in this review.