Usually anemia begins in the early stages of chronic kidney disease and gets worse as kidney function, also known as renal function, decreases. Anemia, when untreated, can be the cause of a poor quality of life. In some cases, people with severe anemia don’t have the energy to even get out of bed. In addition, anemia may cause heart disease, increased hospitalizations, even death. To help people with chronic kidney disease and anemia have more energy to live a better life, anemia management is part of their kidney disease treatment.
In addition to cleaning the blood, kidneys perform other functions. One of those functions is producing the hormone erythropoietin (EPO). Erythropoietin signals bone marrow to produce red blood cells. As renal disease progresses, the diseased kidneys cannot produce enough erythropoietin, therefore, not as many red blood cells are made. This lack of red blood cells is called anemia.
Red blood cells travel throughout the body and provide oxygen to the organs and tissues. When tissues don’t receive enough oxygen, a person feels tired and may experience foggy thinking associated with anemia.
By managing anemia, most people with renal disease can live a better quality of life because they don’t have to suffer with the symptoms of anemia.
Most people with anemia will have one or more of the following symptoms:
If someone with these symptoms talks to his or her doctor, the doctor will perform tests to determine the level and cause of anemia.
There are several clinical tests that can help a doctor determine if a person has anemia. For those with chronic kidney disease the likely cause of anemia is reduced erythropoietin. The doctor will check for iron deficiency and blood loss, which are other common causes of anemia.
Simple blood tests will give values for hematocrit (hct) and hemoglobin (hgb). Low values are an indicator of anemia.
Hematocrit tells the percentage of blood that is composed of red blood cells. When hematocrit falls below 37 percent for men and post-menopausal women or below 33% for women who menstruate, the National Kidney Foundation’s Dialysis Outcome Quality Initiative (K/DOQI) guideline recommends that the cause of anemia be determined and treated in people with kidney disease.
Hemoglobin is the iron-containing protein that gives the blood its red color and carries oxygen to the body’s tissues. If hemoglobin dips below 12 g/dL in post-menopausal women and men and 11 grams per deciliter (g/dL) in women who menstruate, K/DOQI guidelines suggest an anemia work up should be done. Again, this recommendation is for people with kidney disease.
Iron is a mineral in the body that is needed to make healthy red blood cells. Much of the body’s iron is in the hemoglobin. Low iron, like reduced erythropoietin, may also cause anemia. Without iron the body cannot produce enough red blood cells causing Iron Deficiency Anemia. Iron deficiency can be due to a lack of iron-rich foods in the diet, such as red meat, green leafy vegetables and eggs, as well as infection, inflammation or blood loss through hemodialysis, menstruation or other causes.
To treat anemia, iron levels must also be known, so, in addition to blood tests for hematocrit and hemoglobin, the doctor will likely order blood tests for serum ferritin, serum iron, total iron-binding capacity (TIBC) and transferrin saturation (TSAT). The values for these tests will help determine the cause of iron deficiency.
Ferritin is a protein that stores iron. The serum ferritin test shows the total amount of iron stored in the body. Low serum ferritin levels indicate iron deficiency and anemia. (Low ferritin has also been associated with restless leg syndrome.)
Transferrin is a protein that carries iron to bone marrow where it is stored and then used to make new red blood cells. A serum iron test measures the amount of iron that is bound to transferrin in the blood. The normal range for healthy men is 65–177 µg/dL and for healthy women it is 50–170 µg/dL.
The total iron-binding capacity (TIBC) test shows the total amount of iron it takes to completely fill transferrin. This test shows how well transferrin can carry iron to the blood. The normal range for healthy men and women is 240–450 mcg/dL.
The transferrin saturation (TSAT) test is the ratio of serum iron and total iron-binding capacity. Transferrin saturation measures how much iron is bound to transferrin and is readily available to make red blood cells. In healthy people, between 20 and 50 percent of available transferrin sites are saturated with iron.
Values for these tests can vary from lab to lab, the ranges shown here are to provide an idea of what the normal range may be for each test. Each lab will have their normal range by each test on the results page provided to doctors and patients.
Nearly everyone with end stage renal disease has anemia. Before the 1990s, anemia was treated with blood transfusions. Some of the risks of transfusions included allergic reactions, iron overload and infections. Now there are a number of drug options to help with anemia. These drugs are called erythropoiesis-stimulating agents (ESAs) because they stimulate the formation and production of red blood cells.
Recombinant human erythropoietin (rHuEPO) is a protein created in the laboratory that has the same effects as the erythropoietin produced in the body. rHuEPO is given to patients to increase their red blood cell production. People with chronic kidney disease who are not on dialysis go to their doctor’s office for injections. Those doing in-center hemodialysis can get rHuEPO intravenously (IV) while they are at dialysis treatments, if it’s prescribed by their doctor. Brand names of rHuEPO include: EPOGEN® and Procrit®.
Darbepoetin alfa (brand name Aranesp®) is a long-acting erythropoietin protein. It is dosed once weekly or once every other week.
Once the doctor reviews the patient’s blood work and takes into consideration the patient’s health needs, he or she may write a prescription for an ESA, if needed. The National Kidney Foundation advises that people on dialysis should have a target hemoglobin of 11 to 12 grams per deciliter (g/dL). Patients will be monitored by their doctors who will decide the best dose based on their individual medical situation.
If a patient’s hemoglobin does not go up after beginning treatment with an erythropoiesis-stimulating agent, the doctor will recheck iron. Even though there is now a higher level of erythropoietin in the body, there needs to be enough iron for red blood cell production (erythropoiesis) to occur. Usually iron is prescribed by mouth or as an IV injection. Vitamin B-12 and folic acid levels must also be in a normal range for healthy red blood cell production to occur.
In March 2007, the U.S. Food and Drug Administration (FDA) updated the instructions and warnings for the use of the drugs EPOGEN (EPO), Procrit and Aranesp. Recently, several studies have been published regarding the use of anemia medications. These studies focused primarily in the oncology (cancer) and pre-ESRD (pre-end stage renal disease or non-dialysis patient populations). The FDA made the changes to the medications’ labels after reviewing the findings from these studies.
When used as directed the drugs have shown they are safe and effective; however, allowing hemoglobin levels to get too high was linked with an increase in heart attack and strokes.
Anemia management is an important part of improving the quality of life and health of chronic kidney disease and dialysis patients. Treating anemia in people with kidney disease helps prevent fatigue and other symptoms, improves heart health and decreases hospitalizations. Talk to your doctor or members of your health care team to learn more about anemia management.
This site is for informational purposes only and is not intended to be a substitute for medical advice from a physician.
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