Why are oral iron supplements ineffective in treating the iron deficiency in patients receiving chronic HD?
Increasing the Hb from 8 g/dL to 11 g/dL in a 70-kg patient requires the incorporation of 600 mg elemental iron into newly synthesized RBC. Daily iron losses in HD patients are approximately 4 to 7 mg (averaged over dialysis and nondialysis days).
Thus the 2 to 4 mg of oral iron absorbed daily from conventional oral supplements in dialysis patients with elevated hepcidin levels could barely keep pace with ongoing iron losses, and would not allow the patient to repair the accumulated deficit.
Compounding this problem is the phenomenon of functional iron deficiency, which often results in the need for high levels of storage iron to facilitate the release of iron to transferrin and delivery of that iron to the erythroid marrow.
