Anaemia
Anaemia becomes more prevalent as renal function declines. Severe anaemia (e.g. Hb < 100 g/L) due to CKD is uncommon before at least CKD stage G3b. Other causes of a low haemoglobin should always be considered. The management of "renal anaemia" usually consists of erythropoiesis stimulating agents (ESAs - usually based on erythropoietin) and / or iron supplementation. Treating anaemia in patients with CKD has been shown to improve quality of life.
Investigation and management of anaemia in CKD
- Exclude other causes of anaemia.
- When Hb falls below 100-110g/L treatment with intravenous iron ± erythropoiesis stimulating agents may be considered.
- The aim of treatment is to maintain Hb levels in the range 100-120 g/L. (i.e. not to 'normalise' the haemoglobin level).
Useful tips
- Haemoglobin levels both above and below the recommended target range of 100-120 g/L have been associated with adverse patient outcomes in CKD patients receiving ESAs.
- Although iron supplementation is used in the management of "renal anaemia", absolute iron deficiency is NOT a complication of CKD and should be investigated appropriately. (CKD is associated with relative iron deficiency as a result of impaired iron utilisation.)
- The tempo of change in the renal function and haemoglobin level in an individual patient can give useful pointers as to whether the anaemia is likely to be due to the CKD. i.e. stable mild CKD for several years is unlikely to be the cause of a new, progressive anaemia.
- Anaemia due to renal impairment is normally an isolated normocytic anaemia. In patients with anaemia and a macro- or micro-cytosis and / or abnormal levels of white cells or platelets consider other causes.
- Following commencement on an ESA it typically takes 2-3 months to achieve a "steady state" haemoglobin concentration therefore frequent ESA dose adjustments should be avoided.
- Failure to respond to ESA/iron therapy or increased ESA/iron requirements in a patient with stable CKD should prompt re-assessment. Common explanations for this scenario include occult bleeding (especially from the GI tract), ESA non-administration (often withheld on the basis of high blood pressure) or inter-current inflammatory illness (usually infection which blunts the erythropoietic response to ESA-administration).
There are likely to be local algorithms and protocols for management of renal anaemia.
Information for patients
Anaemia (low haemoglobin concentration), is frequently encountered in patients with CKD. It becomes more common with lower kidney function declines. Treatment of the anaemia, once the cause has been established, usually consists of giving patients iron (either in tablet or liquid form to swallow or as an infusion through a drip) and or injections treatment (given weekly to monthly) of a medication known as an ESA or a tablet, usually given three times a week called a HIF inhibitor. With both of these treatments ongoing monitoring is required, and dose adjustments are common.
Ca-PO4-PTH
Calcium, phosphate and bones
Disturbances of calcium and phosphate metabolism arise in moderate to severe CKD (i.e. usually CKD stages G4 and G5). The umbrella term for these abnormalities is CKD-Mineral Bone Disorder (CKD-MBD). CKD-MBD is considered a systemic disorder which is strongly linked to cardiovascular disease and mortality. The key drivers of CKD-MBD are phosphate retention (due to reduced renal clearance), disordered Vitamin D metabolism and consequent secondary hyperparathyroidism.
Detailed guidance on the management of CKD-MBD can be found in the UKKA Commentary on the KDIGO Guideline on the Diagnosis, Evaluation, Prevention and Treatment of CKD-MBD
The key principles of management comprise:
- Maintaining phosphate levels towards the normal range
- Avoiding calcium containing phosphate binders
- Phosphate binders (to minimise dietary phosphate absorption)
- Vitamin D supplementation
The goals of therapy in terms of target calcium, phosphate and PTH concentrations, vary with CKD stage. Many renal units have local protocols for the management of CKD-MBD.
Information for patients
Chronic kidney disease affects the body's ability to handle calcium and phosphate. This, in turn, can lead to problems with your heart, blood vessels and bones. There are a number of different treatment approaches which vary between patients. Options available for treatment include advice on altering your diet, a variety of tablets and, in certain cases, surgery.
See the KFRE information in the CKD stages section for more information.