In CKD, anemia is primarily due to decreased production of which hormone?

• A. Renin
• B. Aldosterone
• C. Erythropoietin
• D. Antidiuretic hormone

Answer: (C)

In CKD, anemia happens mainly because the kidney's ability to produce erythropoietin drops. Erythropoietin is the hormone that stimulates red blood cell production in the bone marrow in response to low oxygen levels. As kidney function declines, fewer peritubular interstitial cells make EPO, so the bone marrow receives less signal to produce new red blood cells. The result is a reduced red cell mass, typically normocytic and normochromic anemia.

The other hormones listed don’t drive red blood cell production. Renin and aldosterone regulate blood pressure and fluid/electrolyte balance, while antidiuretic hormone helps control water reabsorption. Their levels don’t control erythropoiesis, so they don’t explain CKD-related anemia.