Anemia In Chronic Kidney Disease: Symptoms, Causes, And Treatment

Some key functions of your kidneys are filtering blood, removing waste and excess fluid, and stimulating red blood cell production. Chronic kidney disease (CKD) damages your kidneys, preventing them from working as expected. CKD advances slowly, so you may not notice symptoms for some time, but anemia may become a complication as CKD worsens. 

It is estimated that approximately 37 million Americans have CKD. High blood pressure, heart disease, and diabetes are some of the primary risk factors for the condition. But exactly how are chronic kidney disease and anemia related?

Below, we answer this question and many others about anemia in CKD, including: 

  • How common is anemia in CKD? 

  • Who has a higher risk of anemia in CKD? 

  • Symptoms, causes, complications, and treatment of anemia in CKD

But first, here are the basics to better understand how the two health conditions are related. 

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What is anemia? 

Anemia is simply having fewer healthy red blood cells or lower levels of hemoglobin than normal. 

Oxygen is delivered from the lungs to other body parts by red blood cells. Hemoglobin is the iron-containing protein that exists inside the red blood cells and allows them to carry that oxygen. And when red blood cells are fewer than usual or deficient in hemoglobin, organs such as the brain and heart may not get sufficient oxygen to function normally. 

Understanding how anemia is related to chronic kidney disease

Your kidneys usually produce erythropoietin, a hormone that stimulates your bone marrow to produce red blood cells. When CKD damages your kidneys, they make less erythropoietin than normal. And as a result, your body produces fewer red blood cells, causing anemia. 

Anemia is a complication of chronic kidney disease. It's less common in the initial stages of CKD and typically worsens as the kidney disease advances. Anemia in chronic kidney disease is also called anemia of renal disease. 

What causes anemia in chronic kidney disease? 

As mentioned before, the main cause of anemia in CKD is a reduction in the production of erythropoietin in the kidneys (because of CKD). Less erythropoietin than normal results in fewer red blood cells in your body, causing anemia. 

However, many other factors could contribute to the development of the condition, including:

  • Shorter lifespan of red blood cells in the body: If you have chronic kidney disease and anemia, your red blood cells may live for a shorter time than normal inside your bloodstream. As a result, the cells die faster than your body can replace them, causing a shortage of red blood cells. 

  • Iron deficiency: Iron is an essential component of the hemoglobin found in red blood cells. Your blood can't transport oxygen effectively without it. Iron deficiency can occur because of blood loss, your body's inability to effectively absorb the nutrient, insufficient iron in your diet, and higher iron demand than normal (during pregnancy or breastfeeding). 

  • Vitamin B12 deficiency: Vitamin B12 helps produce red blood cells. Deficiency occurs when your body doesn't get or absorb enough vitamin B12. Anemia can be brought on by low levels of this vitamin. Vitamin B12 deficiency is common in people who are over 50 years old. It's also common in vegans, those with stomach or intestinal surgery, and people with digestive conditions such as Crohn's disease.

  • Folate deficiency: Folate is a type of vitamin B. It's also called folic acid and helps your body to form red blood cells. Lower-than-normal amounts of folic acid can cause folate-deficiency anemia, also known as megaloblastic anemia, where your red blood cells are abnormally large. Possible causes of the deficiency include excessive alcohol intake, underlying conditions such as celiac disease, kidney dialysis, and using certain medicines like phenytoin. 

  • Reduction of the bone marrow response to erythropoietin as a result of accumulated toxins

  • Systemic inflammation caused by CKD and associated conditions.

  • Infection

Symptoms of anemia in people with CKD

Anemia in chronic kidney disease usually progresses slowly. It may cause few or no symptoms in the early stages of CKD. If the symptoms develop, they may include the following: 

  • Difficulty concentrating

  • Headaches

  • Pale skin

  • Fainting

  • Palpitation

  • Fast or irregular heartbeat

  • Weakness

  • Sleep problems

  • Fatigue

  • Body aches

  • Shortness of breath

  • Dizziness

  • Chest pains

It’s best to speak to your doctor if you have any of these symptoms. 

How to diagnose anemia

Doctors typically use blood tests, medical histories, and physical exams to detect anemia in CKD patients. 

Blood count tests

Your doctor may use blood tests to diagnose anemia or underlying conditions. In these tests, the healthcare professionals usually take your blood sample to be tested in the lab. 

Blood count tests can reveal several things about your red blood cells: 

  • The average size of your red blood cells

  • The number of red blood cells

  • Hemoglobin (a protein that transports oxygen) amount in red blood cells and blood

  • The number of immature red blood cells in your blood

Your doctor may also use the test to determine the iron amount in your blood and the body's iron stores. Sometimes, your doctor may refer you to a hematologist — a specialist in blood disorders. 

Medical history

Your doctor may ask for this information: 

  • Your family history regarding anemia

  • Over-the-counter and prescription drugs you've been using

  • Medical conditions (current and past)

  • Your symptoms

Physical exam

Your healthcare provider may examine you physically by: 

  • Checking your heart rate

  • Examining your blood pressure

  • Checking your skin's condition

Complications of anemia

With severe anemia in chronic kidney disease, the heart receives insufficient oxygen and works harder to pump adequate red blood cells to other body parts. The risk of heart problems increases because of this.

Moreover, different body organs can fail if you don't treat anemia over time. The condition can also be life-threatening if left untreated for a long period. 

Another possible anemia complication is premature labor. Pregnant women may give birth to underweight babies. And there's also an increased risk of excessive blood loss in pregnancy and higher chances of the infant having fewer than normal red blood cells. 

Restless leg syndrome and esophageal webs are possible complications if severe iron deficiency causes your anemia. 

Chronic or long-term untreated anemia typically affects the cardiovascular (blood circulatory) system, where heart attacks (myocardial infarction), high-output heart failure, arrhythmia (irregular or abnormal heart rhythm), and chest pains (angina) are common complications.   

Anemia treatment in patients with chronic kidney disease

How you treat anemia in CKD depends on the factor or factors affecting your red blood cells, as well as your specific health needs. 

Possible treatment methods for anemia in chronic kidney disease include: 

Treating anemia in CKD with medicine

As mentioned, erythropoiesis is a hormone from the kidney that signals the production of red blood cells. If the levels of erythropoiesis in your body are below normal, your doctor may prescribe an erythropoiesis-stimulating agent (ESA). 

ESAs stimulate the bone marrow to produce more red blood cells. They may reduce your symptoms and eliminate the need for blood transfusions. ESAs may or may not be right for you. If you talk to your doctor, they will help determine whether the medicine is right for you. 

Treating iron-deficiency anemia

Your doctor may prescribe iron supplements if your body's iron stores are low. The supplements may be administered through intravenous infusion or pills to help your body produce healthy red blood cells. If you are on dialysis, your healthcare provider may administer IV iron supplements during the treatment. 

Besides supplements, your doctor may recommend iron-rich foods, such as: 

  • Fish

  • Chicken

  • Meats

  • Turkey

  • Baked beans

  • Dried lentils

Treating vitamin B12-deficiency anemia

Like iron deficiency, your doctor may prescribe oral vitamin B12 supplements if you don't have enough of the nutrient in your body. The healthcare professional may also recommend treating the deficiency with vitamin B12 shots. 

Additionally, you may be directed to eat foods rich in vitamin B12, such as: 

  • Meat

  • Poultry

  • Shellfish

  • Dairy products

  • Eggs

Patients with vitamin B12 deficiency anemia may be advised to reduce or stop alcohol use, as alcohol can interfere with the absorption of vitamin B12. 

Blood transfusions

Sometimes, doctors use blood transfusions to treat anemia in chronic kidney disease. By quickly raising the number of red blood cells in your body, a transfusion temporarily treats anemia symptoms. 

Your doctor may limit this treatment method if there's a risk of iron overload (hemochromatosis) or if your body will likely develop antibodies that may reduce the chances of a kidney transplant. 

Who is at risk of developing anemia in chronic kidney disease? 

The more advanced your kidney disease, the higher the risk of anemia. Chronic kidney disease has five stages — stage five is the most severe, while stage one is the least. 

Older adults over 60 are also at a higher risk of anemia with CKD. 

Additionally, CKD patients who also have diabetes are more likely to get anemia than people without diabetes. People with CKD and diabetes also tend to have anemia earlier and typically with more severe symptoms than non-diabetic individuals with chronic kidney disease. 

How common is anemia in chronic kidney disease? 

The Centers for Disease Control and Prevention (CDC) states that about 37 million American adults have CKD. However, about 40% of people with highly reduced kidney functions who aren’t on dialysis may not be aware that they have CKD. And approximately more than 1 out of 7 kidney disease patients have anemia.¹ ²

The lowdown

The kidney produces a hormone called erythropoietin, which stimulates the bone marrow to produce red blood cells. When CKD damages the kidney, erythropoietin is produced in less-than-normal amounts. 

As a result, the body produces fewer red blood cells, causing anemia in CKD. Other causes include infections, systemic inflammation, and nutritional deficiencies — such as iron, folate, or vitamin B12 deficiencies. Various treatments are available based on the main factor causing anemia in the CKD patient.

  1. Chronic kidney disease basics | Centers for Disease Control and Prevention

  2. Anemia in chronic kidney disease | National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)

Other sources:

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