Dialysis is a life-sustaining treatment for individuals with failing kidneys, yet it often coincides with anemia. While dialysis itself does not directly cause anemia, it frequently exacerbates a pre-existing condition common in individuals with kidney disease. Anemia, characterized by a reduced number of red blood cells, is prevalent among those undergoing dialysis.
Anemia and Chronic Kidney Disease
In individuals with chronic kidney disease (CKD), anemia develops primarily because damaged kidneys cannot produce enough erythropoietin (EPO). EPO is a hormone made by the kidneys that signals the bone marrow to produce red blood cells. When kidney function declines, EPO production decreases, leading to fewer red blood cells. This shortage of EPO is a major factor in the development of anemia in CKD patients, even before they begin dialysis. The severity of anemia often correlates with the degree of kidney function loss.
How Dialysis Influences Anemia
Dialysis, while essential for kidney failure, can intensify anemia through several mechanisms. Patients undergoing hemodialysis can experience small amounts of blood loss during each treatment, as some blood may remain in the dialyzer or lines, or from frequent blood draws for testing. This ongoing blood loss contributes to iron deficiency, a key component needed for red blood cell production.
Chronic inflammation, often associated with CKD and the dialysis procedure, can shorten the lifespan of red blood cells. Red blood cells in dialysis patients may live for only about 70 to 90 days, compared to approximately 120 days in healthy individuals. This inflammation can also suppress the bone marrow’s ability to produce new red blood cells, even with adequate EPO levels.
Iron deficiency is a common issue in dialysis patients, stemming from blood loss and often reduced iron absorption. Dietary restrictions for kidney patients can limit iron-rich foods, and the body’s ability to absorb iron from the gut may be impaired. Nutritional deficiencies, including vitamins like B12 and folate, which are important for red blood cell formation, also contribute to anemia.
Treating Anemia in Dialysis Patients
Managing anemia in dialysis patients involves several approaches aimed at increasing red blood cell production and improving iron levels. Erythropoiesis-Stimulating Agents (ESAs) are a key treatment, acting as a synthetic version of the EPO hormone. ESAs stimulate the bone marrow to make more red blood cells, replacing the missing natural EPO.
Iron supplementation is also a necessary treatment. Dialysis patients often require extra iron, administered orally or intravenously. Intravenous iron is frequently preferred due to better absorption and convenience, as it can be given during dialysis sessions. Optimal iron levels are important for ESAs to work effectively. Nutritional support and minimizing blood loss during medical procedures also contribute to better anemia management.