Chronic kidney disease (CKD) is a disease that affects essential kidney functions such as waste and fluid filtration. In advanced stages, CKD can lead to harmful toxic waste, fluid, and electrolyte buildup in your body.
According to the Centers for Disease Control and Prevention, 15% of American adults¹ suffer from CKD. Unfortunately, most people usually have no clue they have CKD until a doctor officially diagnoses the complication.
As the disease progresses, you may begin to experience anemia-related complications and ask yourself. Is renal anemia associated with CKD? Let's dive into the details to understand better how anemia in chronic kidney disease works.
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Anemia is characterized by a hemoglobin level at least two standard deviations below the mean for your age and gender. Hemoglobin is the protein that carries oxygen found in your red blood cells. Anemia can stem from your body lacking hemoglobin or issues with red blood cells (RBC, erythrocyte) themselves.
Common symptoms associated with anemia include:
Little energy for daily activities
Problem thinking clearly
Dizziness or headaches
Shortness of breath
In extreme cases, you may start feeling depressed or at rock bottom.
Most people with advanced CKD also have anemia. Research² shows that more than 37 million Americans have CKD. Out of those diagnosed with the condition, one out of seven³ has advanced CKD (meaning less than 15% of the kidney is working), making them likely to develop anemia.
The cause of anemia in CKD is not fully established but is multifactorial. The main causes include a decrease in erythropoietin (EPO), a hormone secreted by the kidneys that stimulate the bone marrow to produce red blood cells, and inflammation with increased hepcidin levels.
In many cases, however, anemia is less common during the onset of kidney disease and in earlier stages of CKD. It often worsens as kidney failure progresses, and most kidney function is lost.
The relationship between anemia and chronic disease goes deeper than what meets the eye. Chronic kidney disease causes you to have anemia since your kidneys no longer produce erythropoietin (EPO).
Hormones are responsible for transmitting chemical messages around the body, including to your bone marrow, where your red blood cells (RBC) are produced. When the kidney barely functions, EPO, which tells the body to produce red blood cells, isn't created. As such, the bone marrow doesn't generate new RBCs, your blood cell count drops, and anemia symptoms develop.
Factors that can contribute to the development of anemia in chronic kidney disease include:
Blood loss, including from regular blood transfusion or dialysis treatment
Anemia in CKD develops slowly, especially if you're in the initial stages of kidney failure. As the complication progresses to stages four and five, you may begin to experience one of these symptoms:
Dizziness and loss of concentration: If you're feeling dizzy and having problems concentrating, even for short periods, it's a sign your brain isn't getting enough oxygen due to RBC/hemoglobin shortage in your body.
Chest pain: Regular chest pains in the context of anemia may indicate that your heart is not getting sufficient blood supply to safely supply enough blood to your body. Often, you experience faster heart rates and may develop heart complications after.
Shortness of breath: Lack of enough RBCs means there isn't enough hemoglobin to transport oxygen around your body. Heavy breathing is usually a response by the body to try and supply enough oxygen to the body.
Fatigue or weakness: If you're always tired and lack enough energy to undertake daily activities, even after sleeping, the reason may be that your body cannot supply enough oxygen.
Cold intolerance: Not enough oxygen supply in your body means the cells are not active as they should be. As such, you may be more sensitive to cold.
Paleness: Reduced blood flow in the body means the blood doesn't flow close to the skin. In this case, your skin becomes pale.
If you suspect you have anemia in CKD but are unsure, there are various ways a healthcare professional can diagnose the complication in your body. These include:
The first thing a doctor will look at is your medical history to see whether your anemia is related to CKD. Some of the information on your health history that they might be interested in include:
Current and past medical conditions
Medication, including over-the-counter medicines you take
Family health history
If the results from your medical history are inconclusive, or the doctor suspects you have renal anemia and wants to confirm, they will do a physical exam. During the evaluation, they will examine your:
Body, for rashes, bruises, or any changes in skin color
Another method a healthcare professional can use to get a definitive result on whether you have anemia is through a blood test. Samples of your blood are taken to a laboratory and analyzed for:
A CBC is one of the easiest ways a doctor can check for anemia. Once a sample is taken from your body, it's tested for the number of red blood cells and hemoglobin present. A CBC could also tell how many new RBCs your body produces.
These tests show the amount of iron in your bloodstream, your body's capability to bind to iron, and your liver stores. If the results reveal your body lacks iron, it's probably due to a combination of factors with an increased loss if you’re on hemodialysis, as well as issues with iron recycling in the body.
These tests reveal if your body has enough nutrients to make healthy RBCs regularly. Minerals and vitamins tested include vitamin B12 and folate (also called vitamin B9).
Any of these tests should give a doctor a conclusive answer to whether you have anemia and the cause. Sometimes, you may need to take more than one test if the results of another are inconclusive.
Your anemia treatment depends on why your body isn't making enough RBCs or hemoglobin. If you're showing mild anemia symptoms, a healthcare professional will first treat any underlying conditions that could be the root cause of your anemia, like vitamin and iron deficiency.
Once a cause for anemia in chronic kidney disease is determined, treatment options could include:
If a doctor discovers that lack of iron is the reason for your anemia, they will prescribe iron supplements. These may come as pills or an intravenous (IV) infusion. You can schedule an iron infusion during the treatment if you're already on dialysis due to CKD.
Iron supplements help your body manufacture healthy red blood cells. Common side effects of this treatment may include stomach upset, nausea, diarrhea, and constipation.
If a doctor detects anemia from a lack of vitamins in the body, they'll recommend you take vitamin supplements. Vitamins responsible for making healthy red blood cells include vitamin B12 and folate.
Another treatment your doctor may recommend for your anemia is an erythropoiesis-stimulating agent (ESA). ESAs send a message to your bone marrow to produce more red blood cells, just like erythropoietin would. If you're already on dialysis due to kidney disease, you can receive IV infusion ESAs as part of your dialysis treatment.
If you're not on dialysis, ESAs may be administered as injections. Your doctor may do the shot themselves and later teach you how to give yourself the injections while at home. They may also prescribe some iron supplements to help the ESAs work well and minimize the amount of ESAs you need over time.
Possible side effects of this treatment include pain at the injection point, nausea, and dizziness. Please note that ESAs are not recommended for everyone with anemia in CKD. Although it helps you avoid the risk of blood transfusion, it's best to talk to your doctor about the risks and benefits of ESAs to know if the treatment is good for you.
Healthcare professionals may recommend blood transfusion as a last resort in severe cases of renal anemia. While it's the fastest way to increase your RBC count and relieve anemia symptoms, blood transfusion is a temporary solution.
Doctors use it as a last resort because too many transfusions could cause other health problems, such as developing antibodies that attack donor blood cells and lower the chances of a future possibility of kidney transplant. The iron buildup from repeated transfusions in your body could also cause iron overload, damaging your organs.
Anemia in chronic kidney disease is a common complication that you may experience, especially in the last stages of kidney failure. You will likely develop renal anemia if you are on dialysis or uremic.
Along with the treatment options, you'll need to change your diet, like dropping proteins. Instead, consume foods rich in iron, vitamin B12, and folate. Always talk to your doctor before making any dietary changes.
Chronic kidney disease in the United States, 2021 | Centers for Disease Control and Prevention
37 million American adults now estimated to have chronic kidney disease have-chronic-kidney-disease | National Kidney Foundation
Kidney disease statistics for the United States | National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)
Worldwide prevalence of anaemia 1993–2005 | World Health Organization
Anemia in chronic kidney disease | National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)
Anemia symptoms, causes and treatments | American Kidney Fund