Dialysis patients and anaemia: your questions answered
Why do people on dialysis need extra iron?
The body needs iron to make red blood cells. That’s because iron is one of the building blocks of haemoglobin (HB), a protein which is used by red blood cells to carry oxygen around the body.
Low iron levels lead to anaemia, which can leave you feeling tired, weak, dizzy or lightheaded. If you have anaemia, you could also experience shortness of breath, chest pains or cold hands and feet.
People who are on dialysis usually have low levels of iron. This is because:
- Dialysis can cause bleeding. Losing even a little blood on a regular basis can contribute to iron deficiency.
- The body has natural iron stores and it releases iron as and when it needs it. However, people with advanced chronic kidney disease (CKD) might not release enough iron from their natural stores to meet their needs.
- People with advanced CKD tend to absorb less iron from their diet.
For any or all of these reasons, people on dialysis may need extra iron.
How are dialysis patients’ iron levels monitored?
Patients on dialysis have regular blood tests, including checks on their iron levels. In most kidney units, patients undergo blood tests every month or so.
“Typical tests include measuring haemoglobin levels, as part of a full blood count test,” says Dr Richard Hull, Consultant Kidney Specialist at St George's University Hospitals NHS Foundation Trust and New Victoria Hospital in London.
“Levels of ferritin, a blood protein that contains iron, are also tested. If your blood ferritin level is lower than normal, this means your body’s iron stores are low, you have iron deficiency and could be anaemic.”
Something called transferrin saturation will also be measured regularly.
Dr Hull explains: “Iron binds to a protein called transferrin, which moves the iron through the blood. An iron binding study shows how much iron is bound to transferrin. This is known as transferrin saturation. Low transferrin saturation is an indication of iron deficiency.”
How is anaemia treated for those on dialysis and what is EPO therapy?
“People on dialysis have end stage kidney disease and require high levels of iron to allow them to make blood cells,” says Dr Hull. “For advanced kidney disease we often use intravenous iron as it is more effective than taking iron in tablet form.”
Many patients on dialysis also need erythropoiesis stimulation agents (ESAs) to boost their blood count. These ESAs are man-made versions of the hormone erythropoietin or EPO which is made by the kidneys and instructs your bone marrow to make red blood cells. Damaged kidneys produce less EPO, so ESAs are used to stimulate the bone marrow to produce red blood cells. This kind of treatment is known as EPO therapy.
“For most patients on dialysis, we give EPO intravenously on the dialysis machine,” says Dr Hull. “How often this is done depends on the type of EPO given. Some types of EPO are longer acting so only need to be given fortnightly or monthly. Other EPOs are given three times a week.”
What are the potential side effects of EPO therapy?
High doses of EPO have been associated with an increased risk of cardiovascular events such as strokes. However, it’s often possible to achieve results using a lower dose of EPO combined with a higher dose of iron.
Recent research has confirmed that this is a safe approach for patients on dialysis. In a clinical trial, dialysis patients treated with lower doses of EPO combined with higher doses of iron experienced fewer cardiovascular events compared to those receiving higher doses of EPO and lower doses of iron. The study concluded that giving more iron and less EPO to patients on dialysis can reduce the risk of side effects from EPO.
What do I need to know and share with my kidney team?
“Your kidney team will monitor your iron levels as a routine part of your care,” says Dr Hull. “They will be able to tell you about your blood results and talk about how you can be treated.”
Dr Hull adds that many of his patients on dialysis find it helpful to keep track of their test results online. Speak to your local kidney team about signing up with the system used in your local unit or surgery.
This patient information resource has been made possible with a financial contribution from GSK. GSK has had no editorial input into or control over the content which has been independently owned and created by Kidney Care UK.
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