Kidney Matters - Issue 12 Spring 2021

20
Kidney Clinic
Anaemia: iron comes first
Anaemia is common in people with
chronic kidney disease (CKD). Effective
treatment with iron and, if needed,
erythropoietin (EPO) improves
symptoms, quality of life and physical
functioning in people with CKD.
In anaemia there are fewer than normal red blood
cells, which carry oxygen around the body in a protein
called haemoglobin (Hb). This means that less oxygen
is carried to the body’s organs including the heart, the
brain and muscles, and they do not function as well as
they should.
Iron is key to the development and treatment of
anaemia of CKD (also known as renal anaemia).
This is because, as kidney function gets worse, less
iron becomes available to supply the bone marrow,
where red blood cells are made after stimulation by
erythropoietin (EPO). A hormone produced mainly
by the kidneys, EPO is released into the bloodstream
and travels to the bone marrow where it stimulates the
stem cells to become red blood cells.
What causes anaemia of CKD?
Anaemia starts to develop when kidney function is
less than 60% of normal, and worsens as function
falls. This is why guidelines advise doctors to routinely
check Hb levels at least once a year in CKD stage 3
(30-59%) and at least twice a year in CKD stage 4 (15-
29%) and stage 5 (less than 15%).
According to Professor Sunil Bhandari: “Poor
absorption is one of the most important mechanisms
for iron deficiency in CKD, but you lose additional
iron if doctors take excessive blood tests, and if you
are on haemodialysis (HD) you will lose blood during
treatment. In addition, some medications commonly
prescribed to kidney patients, such as ACE inhibitors
(-pril drugs) and angiotensin receptor blockers (ARBs;
-sartans), cause anaemia by reducing EPO production.”
Sunil is a Consultant Nephrologist and Clinical
Professor, Hull University Teaching Hospitals NHS Trust.
It is also possible for kidney patients to be iron
deficient due to non-renal causes. Women may be
iron deficient because of heavy periods or lack of
dietary iron in pregnancy. Possible causes in both
women and men include bleeding from the gut due
to non-steroidal anti-inflammatory drugs, stomach
ulcers or, very rarely, cancer of the bowel or stomach.
How is anaemia of CKD diagnosed?
Anaemia in people with CKD is defined as Hb less than
110 g/L. The condition has a wide range of symptoms
(see table below), but it can be overlooked by GPs and
other non-specialists.
Table: Symptoms associated with anaemia of
chronic kidney disease
• Weakness
• Fatigue, or feeling tired all the time
• Headaches
• Problems with concentration
• Disturbed sleep
• Paler-than-usual skin
• Itching
• Dizziness
• Shortness of breath
• Chest pain
• Rapid heartbeat
• Feeling cold
• Feeling depressed
www.kidneycareuk.org