Kidney Matters - Issue 12 Spring 2021

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Sunil explains: “The problem is that kidney patients
do not present with the classic symptoms of anaemia
alone. Shortness of breath is not just a symptom of
anaemia; it is also a symptom of acidosis and fluid
retention, which both occur in CKD. However, if a kidney
patient is tired all the time, is short of breath, and looks
pale, they need a blood test to check the Hb level.
“If Hb is less than 110 g/dl, we test blood levels of
ferritin (a measure of stored iron) and transferrin
saturation (TSAT), which checks how much iron is
binding in the blood and is available. A serum ferritin
of less than 100 mcg/L and/or TSAT of less than 20%
indicate iron deficiency. We also check blood levels
of vitamin B12 and folate, which are important for
producing red blood cells. If kidney patients cannot
eat well, they can become malnourished and develop
vitamin deficiencies. They may also not be able to
absorb vitamins effectively,” he adds.
How is anaemia of CKD treated?
Vitamin B12 or folate levels can be improved with
supplements, given either as tablets or injections
in the case of vitamin B12. Otherwise, treatment of
anaemia of CKD involves iron supplementation, plus
ESA (erythropoiesis stimulating agent) injections if
needed to replace EPO.
Although a diet high in iron is conventionally advised
to improve iron deficiency, it is not as effective in CKD
as in the general population. People with CKD cannot
absorb enough dietary iron from the gut, especially
as intake of iron-rich foods may be limited by dietary
restrictions in people with late-stage CKD.
“Iron is key to the
development and
treatment of anaemia of
chronic kidney disease “
How is iron treatment given?
Some guidelines recommend a trial of oral iron for
people with CKD who do not need dialysis or who are
on peritoneal dialysis (PD). However, high doses are
needed to ensure enough iron is absorbed, and the
tablets may be difficult to tolerate.
“In my experience, patients do not like the side effects
of oral iron like black stools, diarrhoea or constipation.
Oral iron needs to be taken on an empty stomach
(30 minutes before eating or at least two hours after
eating) for the best chance of absorption, which
increases side effects. Iron also will not be absorbed
if taken at the same time as medications that act on
the gut such as phosphate binders, proton pump
inhibitors or ranitidine,” comments Sunil
In contrast, high-dose iron given through an infusion
into a vein (intravenously) bypasses the gut. It is
absorbed straight into the bloodstream and rapidly
increases iron levels in the blood.
Intravenous iron is generally well tolerated. The most
common side effects include a metallic taste in the
mouth, feeling sick, headache and dizziness.