By Stephanie Wright, DNP, AGACNP-BC, RN, MSN, MBA with the American Nephrology Nurses Association
What is Anemia?
Anemia is a condition in which the body does not have enough red blood cells. Red bloods cells are important because they carry the oxygen needed by the cells and tissues in the body to function properly and survive. With anemia, the major organs of the body such as the heart, kidneys, lungs and brain may lack essential oxygen to carry out normal functioning and if severe enough, cells may die.1
What Do the Kidneys Have to Do with Anemia?
If you have been diagnosed with chronic kidney disease (CKD), you may wonder why you feel fatigued and tired. The answer maybe because you have anemia. The kidneys release a hormone called erythropoietin that plays a role in the production red blood cells. Oxygen from the lungs attach to red blood cells to be used by the cells and organs of the body. When erythropoietin is released by the kidneys, it stimulates the bone marrow to produce mature red blood cells. When the kidneys are damaged, there is a reduction in the release of erythropoietin. As a result, bone marrow production of mature red blood cells is decreased, leading to anemia and reduced oxygen to vital organs of the body. Anemia in CKD may manifest in the early stages, when there is a 25-50% reduction in kidney function.2 As kidney disease progresses, anemia tends to get worse. Nearly all people with End Stage Renal Disease (ESRD), when the kidneys function at 15% or less, have anemia.2 Anemia in kidney disease is associated with poor outcomes such as increased hospitalizations, cognitive impairment, cardiovascular disease, reduced quality of life and increased risk of death.2
What are Other Causes of Anemia in Kidney Disease?
Other causes of anemia in CKD include, blood loss from hemodialysis and deficiency in key nutrients such as iron, folic acid or vitamin B12.1 Folic acid is a type of B vitamin called vitamin B9. Folic acid deficiency occurs in less than 10% of all kidney disease patients, particularly in patients on hemodialysis, because folic acid is dialyzed out of the blood stream during hemodialysis.3 Folic acid works closely with vitamin B12 and iron to ensure adequate DNA synthesis of red blood cells.4 In the absence of folic acid or vitamin B12, red bleed cells become larger than normal, a term called macrocytic and more oval shaped. In the absence of iron, red blood cells become smaller (microcytic) and lighter in color (hypochromic).4 These irregularly shaped cells do not live as long and normal red blood cells.4
In addition to deficiency in key nutrients such as iron, folic acid and vitamin B12, other causes of anemia in kidney disease include inflammation that occurs with infection and chronic illnesses in which the immune system attacks normal cells of the body such as lupus and arthritis.1 Inflammation prevents the kidneys from making the hormone erythropoietin and promotes death of red blood cells that are not mature.4
In patients with kidney disease, there is a greater risk of anemia in the following:5
- African Americans
- Moderate to severe loss of kidney function - CKD stages 3 and 4
- End stage kidney loss – CKD stage 5
What are the Signs and Symptoms of Anemia in Kidney Disease?
Typical signs and symptoms of patients with anemia include:1,5
- Chest pain
- Shortness of breath or difficulty breathing
- Intolerance to cold temperatures
How is Anemia Diagnosed in Patients with Kidney Disease?
Although anemia is common in patients with kidney disease, not all patients have symptoms of anemia.5 Blood test to check hemoglobin level is used to diagnose anemia. Hemoglobin is the part of the red blood cell that carries oxygen. When hemoglobin is low, anemia is likely. Further blood tests can be performed to determine what type of anemia is present such as iron, folic acid and Vitamin B12 levels.5
What is Treatment for Anemia in Kidney Disease?
In treating anemia, identification of the cause is important. If someone has moderate to severe loss of kidney function, medications can be given to stimulate the production of red blood cells called erythropoiesis stimulating agents (ESA’s).5 ESA’s are given as injections under the skin.5
In patients who have anemia caused by a deficiency in iron, folic acid or vitamin B12, these key nutrients are given as supplements in the form of pills or injections. Increase dietary intake of these nutrients in food are also encouraged.
Read more about Anemia in AAKP's Understanding Anemia of Chronic Kidney Disease brochure.
- National Institute of Diabetes and Digestive and Kidney Diseases. (n.d.). Anemia in chronic kidney disease. Retrieved from https://www.niddk.nih.gov/health-information/kidney-disease/anemia#:~:targetText=When%20kidneys%20are%20diseased%20or,red%20blood%20cells%2C%20causing%20anemia.&targetText=Other%20common%20causes%20of%20anemia,iron
- Kidney Disease Quality Outcomes Initiatives (KDOQUI, 2006).
- Zadrazial, J., Horak, P. (2015). Pathophysiology of anemia in chronic kidney disease: A Review. Biomedical Papers of Medical Faculty University of Palacky Olomouc Czech Republic, 159(2):197-202.
- Tsagalis, G. (2011). Renal anemia: a nephrologist’s view. Hippokratia 15(1), 39-43. Retrieved from https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3139678/pdf/hippokratia-15-39.pdf.
- National Kidney Foundation. (2015). Anemia and chronic kidney disease. Retrieved from https://www.kidney.org/atoz/content/what_anemia_ckd
Dr. Wright has almost 20 years of experience in nephrology nursing. She is currently an Nurse Practitioner/Nurse Manger for Kidney-Pancreas Transplant at Augusta University Medical Center. Dr. Wright has published in American Nephrology Nursing Journal. She won a writing award for her research and publication in American Nephrology Nursing Journal entitled: "Using Evidence-Based Practice and an Educational Intervention to Improve Vascular Access Management: A Pilot Project. She has conducted many oral and poster presentations related to nephrology nursing. Dr. Wright served as an Editor for Core Curriculum of Nephrology Nursing. She has also served as the Publication Advisor and currently Leader of American Nephrology Nursing Administrative Specialty Practice Network. Dr. Wright has a passion for working with kidney patients and is dedicated to improving outcomes for this patient population.