EPO and chronic kidney disease: The mechanisms of anemia in CKD include shortening red blood cell (RBC) survival, relative erythropoietin deficiency, folate or vitamin B12 deficiency due to anorexia, functional iron deficiency due to poor dietary iron absorption, higher iron requirements during erythropoietin supplementation, and overproduction of hepcidin—a regulator that inhibits iron transport by binding to ferroportin—in a chronic inflammation state [119].