Date Published: 
Friday, 29 August, 2014

Iron deficiency in nephrology

Iron deficiency is a common disorder among patients with chronic kidney disease (CKD). A large-scale, epidemiological analysis conducted in 2009 suggests that the majority of patients with impaired kidney function (identified by reduced creatinine clearance) have low levels of iron, with approximately 58% of men and over 70% of women reaching the haematological definition of iron deficiency (See figure below)1. Rather than being a feature of later stages of disease only, iron deficiency has been reported from as early as CKD stage 31.

Figure 1. Percentage of patients with chronic kidney disease and iron deficiency1

Copyright permission obtained from Fishbane et al, 2009.

Gender differences in iron deficiency parameters of patients with CKD

Results from the 2009 National Health and Nutrition Examination Survey show that the prevalence of iron deficiency is significantly higher in female patients with CKD compared with their male counterparts (72 vs 58%; p<0.0001). Additionally, in women, haematological parameters of iron deficiency (serum ferritin and transferrin saturation) appear to share a linear relationship with renal function, with serum ferritin increasing (p<0.0001) and transferrin saturation decreasing (p=0.02) with worsening CKD stage (see figures below). No such relationship was observed in male patients with CKD1.

Figure 2. Gender differences in mean serum ferritin (top) and mean transferrin saturation (bottom) at different stages of CKD.

Copyright permission obtained from Fishbane et al, 2009.

Iron deficiency anaemia in CKD 

Iron deficiency is one of the most common causes of anaemia (iron deficiency anaemia). However, not all patients with iron deficiency are anaemic, and not all patients with anaemia have iron deficiency anaemia. The prevalence of anaemia (as defined by the World Health Organization haemoglobin targets2) in patients with CKD is approximately 6% in women and 10% in men3. Among CKD patients with iron deficiency, the rate of anaemia is 11–27%1.

Clinical implications of iron deficiency

Iron deficiency and iron deficiency anaemia are important clinical concerns in CKD. Severe anaemia in this patient group is associated with an increased risk of mortality, cardiovascular complications, and a significant reduction in quality of life4. Every 1 g/dL reduction in haemoglobin level is associated with a 5% increase in the risk of mortality and 4% increase in the risk of hospitalisation for patients with CKD5.

Iron deficiency is, in itself, associated with many of the symptoms more typically linked with anaemia (see table below). Studies suggest that iron replacement therapy can improve symptoms and help to restore quality of life of patients with iron deficiency6.

To find out more about the latest research into iron deficiency in patients with chronic kidney disease please click here.

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