Article

Anemia symptoms, causes and treatments

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There's more to chronic kidney disease than you think. If your kidneys are not working properly, they may not be able to help your body make the red blood cells it needs. Anemia is a common side effect of kidney disease.
Medically reviewed by
AKF's Medical Advisory Committee
Last updated
November 9, 2021

What causes anemia?

Anemia happens when there are not enough healthy red blood cells in your body. Red blood cells carry oxygen through your bloodstream, giving you energy and helping your muscles, bones, and organs work properly. Anemia can make you feel weak and tired because you are not getting the energy you need.

Red blood cell

Normal

The oxygen that we breathe in passes through our lungs and into the red blood cells.

Red blood cell - anemia

Anemia

In anemia, there are not enough red blood cells to carry this oxygen around the body.

How does chronic kidney disease (CKD) cause anemia?

Anybody can develop anemia, but it is very common in people with CKD. People with CKD may start to have anemia in the early stages of CKD, but it is most common in stages 3-5. Anemia usually gets worse as CKD gets worse. If your kidneys are not working as well as they should, you are more likely to get anemia.

If you think you might have CKD, talk to your doctor about getting tested. Management of anemia and its symptoms may help you feel better.

Anemia in CKD is more common if you:

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Have diabetes

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Have heart disease

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Have high blood pressure

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Are African-American

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Are older than 75 years

What are the symptoms of anemia?

Anemia can happen with or without symptoms. Many of the symptoms of anemia can also be caused by other problems.  The only way be sure if you have anemia is to get tested. If you are experiencing symptoms, it is important that you talk to your doctor.

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Dizziness, loss of concentration

Feeling dizzy or having difficulty concentrating may be a sign that your brain is not getting enough oxygen.

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Pale skin

Paleness is caused by reduced blood flow or a lower number of red blood cells.

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Chest pain

Anemia in CKD can increase your risk of heart problems because the heart has to work harder to provide blood to your body. If you experience an unusually fast heart rate or are worried about your heart health, please speak to your doctor.

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Shortness of breath

Your blood may not have enough red blood cells to deliver oxygen to your muscles. By increasing your breathing rate, your body is trying to bring more oxygen into your body.

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Fatigue or weakness

Easy fatigue, loss of energy, and reduced physical capacity

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Cold intolerance

Sensitivity to the cold may mean there is not enough oxygen being delivered in the blood to your body

What type of anemia is common in people with CKD?

There are two main causes of anemia in CKD:

Less erythropoietin (EPO) than normal

All of the cells in your body live for a certain amount of time and then die. Your body is always working to make new cells to replace the ones that have died. Red blood cells live for about 115 days. Your kidneys help your body make red blood cells.

Healthy kidneys make a hormone called erythropoietin (EPO). EPO sends a signal to the body to make more red blood cells. If your kidneys are not working as well as they should, they can't make enough EPO. Without enough EPO, your body doesn't know to make enough red blood cells. This means fewer red blood cells are available for carrying oxygen through your body, leading to anemia.

Chart of a healthy kidney versus a ckd kidney

Less iron than normal 

Iron is a mineral found in many foods, such as meats and leafy greens. Your body uses iron to make red blood cells. A common cause of anemia in people with CKD is iron deficiency. Iron deficiency means you do not have enough iron in your body. It can be caused by not getting enough iron in your diet or by losing blood, either through blood tests or during dialysis. If you don't take in enough iron through your diet, you can get anemia. Around half of people with CKD stages 2 to 5 have some kind of iron deficiency.

Other types of anemia

Anemia caused by having too little EPO or too little iron in your body are the most common in people with CKD. However, there are also other types of anemia. Talk to your doctor to learn more.

Causes of iron deficiency

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Not eating enough foods that are rich in iron

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Iron from your food is not being absorbed properly into your bloodstream

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Frequent blood donation or testing may increase demand for iron

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Blood loss from dialysis

How will I know if I have anemia?

Talk to your doctor if you think you may have anemia. The only way to know if you have anemia is to have a blood test. When you have kidney disease, your doctor will want you to have blood tests often. These tests are used to check not only your kidney function, but also for signs of any other problems, such as the number of red blood cells and how much iron you have in your body.

The test for anemia is a simple blood test to check for the amount of hemoglobin in your blood. Hemoglobin is a part of your red blood cells. Figuring out the amount of hemoglobin you have in your blood can tell your doctor how many red blood cells you have.

Your doctor may also ask you if you've noticed any symptoms, such as changes in skin color or feeling unusually tired.

How is anemia treated?

Getting your anemia treated can help you feel better. Depending on the cause of your anemia, your doctor may recommend one of the following treatments:

  • Erythropoiesis-stimulating agents (ESAs)  — ESAs are injectable medicines that work by sending a signal to the your body to make more red blood cells.
  • Iron supplementation  — Your doctor may give you iron supplements as pills or as a shot. If you are on dialysis, you may be given an iron supplement during your dialysis treatment.
  • Red blood cell transfusion  — A red blood cell transfusion is a procedure to increase the number of red blood cells in your body by giving you red blood cells from someone else's body through an IV. This can temporarily improve your anemia symptoms.

Doctors and researchers are working on potential new treatments for anemia. New treatments in development are tested in clinical trials. If you're interested in joining a clinical trial to try an investigational new treatment for anemia, visit ClinicalTrials.gov to learn about all available clinical trials for anemia.

If you have CKD, getting early treatment for your anemia can help slow the progress of your CKD. If you think you might have anemia, talk to your doctor about getting tested.

Anemia and end-stage renal disease (ESRD)

Anemia and end-stage renal disease (ESRD), also known as kidney failure, often go hand in hand. Most people with kidney failure who are on dialysis have anemia. Kidney transplant patients are also at higher risk for anemia. Learn more.

Talk with your doctor about anemia

Talk with your doctor or another member of your health care team to find out more about your anemia symptoms and treatment options. Our Talk to Your Doctor Guide can help you get the conversation started.

Watch: Video resources on anemia and kidney disease

Common questions about anemia in kidney disease

How are patients with kidney disease and anemia treated?

Iron supplementserythropoiesis-stimulating agents (ESAs) and red blood cell transfusions are current treatment options for anemia in chronic kidney disease (CKD). Doctors and researchers are working on potential new treatments for anemia that can be administered orally (by mouth) and may provide another option for treatment.

Can kidney disease cause anemia?

Anemia is more common in people with chronic kidney disease (CKD) and it can be caused by your CKD. Anemia happens when there are not enough red blood cells in your body. When your kidneys are not working like they should, your body may produce fewer red blood cells. Also, people with anemia and chronic kidney disease have lower levels of iron which is also used to make red blood cells. Fewer red blood cells means less oxygen is carried to your organs and tissues. Learn more.

What type of anemia is associated with chronic kidney disease?

There are several kinds of anemia. The most common types of anemia in people with chronic kidney disease (CKD) are anemia caused by having too little of a hormone called erythropoietin (EPO) and anemia caused by having too little iron in your body. Learn more.

Is anemia a sign of kidney disease?

No, having anemia does not always mean you have kidney disease. However, anemia is a common complication of kidney disease. Anemia happens when there are not enough red blood cells in your body. If your kidneys are not working properly, they may not be able to help your body make the red blood cells it needs. Learn more.

Does anemia cause kidney disease?

No, anemia does not cause kidney disease. Anemia is a complication of CKD. People with CKD may start to have anemia in the early stages of CKD, though it is most common in people with stages 3-5 CKD. Anemia usually gets worse as your kidney function gets worse. 

Can low iron affect kidneys?

People with anemia and chronic kidney disease (CKD) may have lower levels of iron which is used to make red blood cells. This can be caused by not getting enough iron in your diet or by losing blood, either through blood tests or during dialysis. Fewer red blood cells means less oxygen is carried to your organs and tissues. Learn more.

What are some of the signs and symptoms of anemia in chronic kidney disease patients?

Anemia can happen with or without symptoms. Many of the symptoms of anemia can also be caused by other problems. The only way be sure if you have anemia is to get tested by your doctor. Signs or symptoms of anemia include:

  • Dizziness
  • Loss of concentration
  • Pale skin
  • Chest pain
  • Shortness of breath
  • Fatigue or weakness
  • Sensitivity to cold

Learn more about the symptoms of anemia.

Are there foods you can eat to help with anemia when you have chronic kidney disease?

If your body does not have enough iron, a dietitian or health care professional may recommend you add more foods with iron to your diet. Foods high in iron include: shellfish, spinach, red meat, beans and broccoli. However, some of these foods may be high in other nutrients, like sodium, phosphorus, or potassium, which people with chronic kidney disease (CKD) may need to limit. Talk with your health care team before making changes to your diet. Learn more about eating healthy with kidney disease.