What is the most common cause of anemia in chronic kidney disease, and what therapy addresses it?

• A. Reduced erythropoietin production; treat with erythropoiesis-stimulating agents and iron supplementation.
• B. Iron deficiency from GI losses; treat with iron supplementation alone.
• C. Folic acid deficiency; treat with folate supplementation.
• D. Bleeding during dialysis; treat with transfusions.

Answer: (A)

In chronic kidney disease, the most important issue driving anemia is the kidneys’ reduced production of erythropoietin, the hormone that signals the bone marrow to make red blood cells. When EPO levels fall, red cell production drops, leading to a normocytic, normochromic anemia that is typically the dominant feature of CKD-related anemia.

The best therapy targets both the missing EPO signal and the iron needed to build hemoglobin. Erythropoiesis-stimulating agents replace or mimic the effect of natural EPO to stimulate red blood cell production. Because producing new red cells requires iron, iron supplementation is often given alongside ESAs to ensure there is sufficient iron available for erythropoiesis. In many patients on dialysis, this iron is given intravenously.

Other factors like iron loss from GI sources, folate deficiency from dialysis, or bleeding during dialysis can contribute to anemia, but they do not account for the prevalence and the main mechanism as effectively as EPO deficiency does.