Limiting iron supplementation for anemia in dialysis patients--the Basis for Japan's conservative guidelines.

Both the Kidney Disease Outcomes Quality Initiative (KDOQI) Guidelines and the European Best Practice Guidelines (EBPG) support the use of substantial doses of iron supplementation when iron overload cannot be confirmed. However, excessive iron reduces iron utilization and is involved in the generation of intracellular reactive oxygen species, which induce cell injury; the risk of subtle toxicity from iron excess exists. Unnecessary iron supplementation also accelerates hepcidin (HP) production. HP, via its effect on ferroportin 1 (FP-1), keeps intracellular iron from being carried even if the iron storage is adequate; it also decreases iron absorption from the intestine. The Japanese Society for Dialysis Therapy Guidelines propose that a minimal amount of iron should be given to chronic kidney disease patients with anemia and only in cases of evident iron deficiency. Japanese clinicians believe that the risk/benefit ratio for iron supplementation is higher than that accepted in Western countries. When erythropoiesis-stimulating agent hyporesponsiveness exists, we should consider conditions other than iron deficiency and treat these conditions to improve iron utilization.