Considerations for optimal iron use for anemia due to chronic kidney disease

Background: Availability of recombinant human erythropoietin (rHuEPO) has i mproved the treatment of anemia due to chronic kidney disease (CKD). Iron d eficiency is the most common cause of resistance to rHuEPO therapy, contrib uting to ineffective erythropoiesis and hematocrit/hemoglobin values below the recommended target range (33%-36%/11-12 g/dL). IV iron supplementation is necessary to meet increased iron demands from stimulation of erythropoie sis and chronic blood loss; however, questions remain as to the optimal sup plementation strategy to maintain appropriate yet safe iron status. Treatme nt guidelines for anemia management have been developed through the Nationa l Kidney Foundation Kidney Disease Outcomes Quality Initiative (NKF-K/DOQI) . Objective: This review presents the basis of need for the NKF-K/DOQI guidel ines and includes detailed information concerning iron physiology, metaboli sm, iron preparations, and evaluation of iron status. Methods. This review was based on a MEDLINE search and complemented by refe rences from the NKF-K/DOQI guidelines (whose review extended beyond MEDLINE ). References focusing on normal iron physiology and metabolism, alteration s in iron physiology in patients with CKD, laboratory evaluation methods, a nd strategies for iron supplementation were obtained from MEDLINE and revie wed for content. Results: Controversy over appropriate use of iron supplementation has led t o disparity in accepted practice procedures. Oral iron (ferrous salts and p olysaccharide iron complex) and IV iron preparations (iron dextran, sodium ferric gluconate, and iron sucrose) are available. Problems with oral iron supplementation include limited absorption and patient noncompliance. Altho ugh most available data on IV iron use in the United States are specific to iron dextran preparations, published information based on clinical use of sodium ferric gluconate and iron sucrose products has been promising. The u se of chronic IV iron administration to sustain iron stores has been more w idely accepted to prevent development of absolute and functional iron defic iency. Conclusions: Although iron therapy is commonly warranted in patients with C KD. questions remain as to the most favorable supplementation strategy to o ptimize therapy through improvements in hematocrits, efficient use of rHuEP O, and maintenance of appropriate and safe iron levels. Clinicians will nee d to devise strategies based on the compilation of information from clinica l experience and the available literature. Clinical practice guidelines dev ised by the NKF-K/DOQI have provided a useful tool for the medical communit y using both these resources.