Why are people with Chronic Kidney Disease (CKD) at Risk of Iron Deficiency?
If you have been diagnosed with chronic kidney disease, commonly known as CKD, your chances of having anaemia increase. Iron deficiency could be playing a role in this anaemia.
Chronic kidney disease occurs when you have kidney damage or reduced kidney function for more than three months.1 It can be caused by many factors, such as high blood pressure and diabetes. Your doctor may tell you that you have a particular stage of CKD between stage 1 and stage 5, where 5 is the most serious. The stage of your disease is calculated using a measurement known as the glomerular filtration rate, or GFR. Lower GFR values mean that you have a higher stage of CKD and may require more treatment for your reduced kidney function.
As your stage of CKD becomes more advanced, it becomes more likely that you will also suffer from anaemia. Anaemia occurs when you don’t have enough haemoglobin in your red blood cells to carry the normal amount of oxygen around your body. Nearly all patients with CKD stage 5 are anaemic.2
If you do become anaemic with your CKD, iron deficiency could be one of the causes. Up to half of people with CKD stages 2-5 have some form of iron deficiency.3 Iron deficiency in CKD occurs when the supply and demand for iron in your body goes out of balance. This might happen because of:
- Blood loss (and therefore iron loss) from:
- Frequent blood tests4
- Dialysis, if your condition is this advanced4
- Lower iron intake, caused by:
- Eating less foods that are rich in iron3
- Reduced absorption of iron from your food into your blood stream5
If you have CKD you may also have a type of anaemia called ‘anaemia of chronic disease’. The inflammation often associated with the anaemia of chronic disease can lead to iron deficiency due to decreased iron absorption from the GI tract or decreased release from iron stores.5
You might also become iron deficient if you are treated with an erythropoiesis-stimulating agent, commonly known as ESA.
One role of your kidneys is to produce the hormone erythropoietin, which stimulates the production of red blood cells in your bone marrow.5 If you have CKD, your kidneys may not produce enough erythropoietin and you may develop anaemia. You may be given an erythropoiesis-stimulating agent (ESA)2 to treat your anaemia. Like the erythropoietin that healthy kidneys make, ESAs signal the bone marrow to produce and increase the number of red blood cells in your body.5 Since the production of healthy red blood cells requires iron, ESAs can quickly use up the iron stores in your body causing you to become iron deficient.5 Because of this you may need to be given extra iron so that there is enough iron to make haemoglobin in the new red blood cells.6
Treatment of your anaemia and iron deficiency with an ESA and iron (either by mouth or by injection) should help you to feel less tired and generally increase your feeling of well-being. Doctors also treat anaemia as it can contribute to the progression of kidney disease and can increase your risks of heart failure or other cardiovascular problems.3
Both iron deficiency and anaemia are common problems for patients on haemodialysis due to blood loss in the dialysis filter, frequent blood tests, and bleeding at the haemodialysis access site and other sites in the body including the gastrointestinal tract.4
If you are on dialysis it is likely that your doctor will be monitoring your iron status but if you are concerned about iron deficiency, your CKD, or your treatment, it is important that you talk to your doctor or dialysis nurse.
- National Kidney Foundation. K/DOQI Clinical practice guidelines for chronic kidney disease: Evaluation, classification, and stratification. Am J Kidney Dis. 2002;39:S1-S266r.
- Babitt JL, Lin HY. Mechanisms of anemia in CKD. J Am Soc Nephrol. 2012;23(10):1631-4.
- Mehdi U, Toto RD. Anemia, diabetes, and chronic kidney disease. Diabetes Care. 2009;32(7):1320-6. doi:10.2337/dc08-0779.
- Fishbane S, Pollack S, Feldman HI, Joffe MM. Iron indices in chronic kidney disease in the National Health and Nutritional Examination Survey 1988-2004. Clin J Am Soc Nephrol. 2009;4(1):57-61. doi:10.2215/CJN.01670408.
- Wittwer I. Iron deficiency anaemia in chronic kidney disease. J Ren Care. 2013;39(3):182-8.
- Aapro M, Österborg a, Gascón P, Ludwig H, Beguin Y. Prevalence and management of cancer-related anaemia, iron deficiency and the specific role of i.v. iron. Ann Oncol. 2012;23(8):1954-62. doi:10.1093/annonc/mds112.