Vitamin D and anemia in chronic kidney disease

A considerable proportion of patients with chronic kidney disease develop anemia. Several factors are known to contribute to this renal anemia, like EPO deficiency, EPO hyporesponsiveness and functional iron deficiency due to increasing concentrations of hepcidin. Recent studies showing an association in abnormalities of the vitamin D system with low hemoglobin (Hb) levels and erythropoietin stimulating agent (ESA) resistance suggest cross-talk between the vitamin D system and erythropoiesis. The administration of either inactive or active vitamin D has been associated with an improvement of anemia and reduction in EPO hyporesponsiveness. Potential links between the vitamin D system and erythropoiesis are described in this chapter.