How Chronic Kidney Disease Can Cause Anemia
We know that our kidneys help filter many toxins from our body, which are then expelled through urine. But what some people may not realize is how well our kidneys work affects our body function overall. For example, most people with chronic kidney disease (CKD) develop anemia, a condition where the blood has too few red blood cells. Red blood cells transport oxygen throughout your body, providing energy to the tissues, including your heart and brain. Decreased oxygen supply to your body’s tissues can result in symptoms, such as fatigue, feeling cold, confusion, rapid heartbeat, and more.
Your Kidney’s Connection to Anemia
Your kidneys produce a hormone called erythropoietin (EPO), which stimulates your bone marrow to produce red blood cells. In order to determine how much EPO to produce, the kidneys monitor how much oxygen is flowing through your body via the red blood cells. When there is too little oxygen, healthy kidneys increase EPO production, which in turns provides your body with more red blood cells. But this system breaks down if you have chronic kidney disease. As the disease progresses, your kidneys produce less EPO over time, which results in fewer red blood cells.
Anemia can begin fairly early. In some cases, people who have only lost 20 to 50% of normal kidney function develop it, but the less kidney function you have, the more likely you are to have anemia.
Decreased EPO production is not the only way someone with chronic kidney disease can develop anemia. It may also be caused by low levels of iron, vitamin B12 and folic acid. People with chronic kidney disease who undergo hemodialysis are also at risk because of the blood loss that occurs during the procedure.
You are at higher risk of developing iron-deficiency anemia if you have stage 2 through 5 chronic kidney disease.
Chronic Kidney Disease and Your Anemia Risk
Most people with chronic kidney disease do develop anemia at some point, but some people are at higher risk of developing this complication than others. They include people who:
Have heart disease or high blood pressure
Are older than 75 years old
Have moderate or severe loss of kidney function (CKD stage 3 or 4)
Have kidney failure (stage 5)
Treating Anemia Caused by Chronic Kidney Disease
Treatment for anemia caused by chronic kidney disease varies depending on the cause. Blood tests will tell your nephrologist the likely cause of your anemia. If it is due to low EPO production, you may be given medications to stimulate production. Called erythropoiesis-stimulating agents (ESAs), these medications send a message to your body to produce more EPO. The drugs are given by injection and some people are taught to self-administer the injections, allowing them to take them at home.
If your anemia is caused by low iron levels, particularly if you are undergoing dialysis, you may be given iron supplements, either in pill form or via infusion. You may also be advised to take B12 and folic acid supplements. Blood transfusions can provide you with an increased supply of red blood cells, regardless of the original cause of anemia, but this is a temporary solution and may need to be repeated if your body does not produce its own red blood cells.
Diet is an important issue when you have chronic kidney disease and it may be even more complicated if you have also developed anemia. To treat anemia with food, you would need to eat products rich with iron, B12 and folic acid; but some of those foods may also include substances you need to avoid, such as sodium. A dietitian, particularly one who works with people who live with chronic kidney disease, may help you learn which foods are best and which to avoid.
Anemia is a serious condition that should be treated. It can lead to other complications, such as heart disease. As long as your kidneys are not functioning properly, you are at risk for developing the condition. By speaking with your doctor and following your treatment plan, you may slow down the progress of both your kidney disease and anemia.