The function of the kidneys is to filter waste products from the blood stream. Additionally, kidneys play a significant role in regulating blood pressure, electrolyte balance, and red blood cell production. Blood enters the kidney through the renal artery. In the kidney, the blood is passed through nephrons, where waste product and excess water are filtered out from the bloodstream.
Chronic kidney disease is a general term for a heterogeneous disorder affecting the function and structure of the kidney. It is difficult to determine the exact cause of chronic kidney disease. However, chronic kidney disease is often associated with old age, hypertension, diabetes, obesity and cardiovascular disease. Most chronic kidney disease patients eventually become anemic. The severity of anemia increases as the functionality of the kidney decreases.
Anemia is the deficiency of red blood cells or of hemoglobin in the blood. The World Health Organization (WHO) defines anemia as a hemoglobin concentration lower than 13.0 g/dl in men and postmenopausal women, and 12.0g/dl in other women.
Deficiency of erythropoietin is the primary cause of anemia associated with chronic kidney disease. Other causes of anemia in chronic kidney disease are blood loss, shortened red cell life span, uremic milieu, iron deficiency and inflammation. Recombinant erythropoietin (rhEPO) is administered to chronic disease patients to treat anemia.