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, slow renal progression and reduce adverse cardiovascular outcomes.
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).
- 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 the management of renal anaemia.
Information for patients
Anaemia, or a low haemoglobin concentration, is frequently encountered in patients with CKD. It becomes more common as renal 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 erythropoietin (sometimes called “EPO”) based injections. Patients tend to have a variable response to these treatments such that ongoing monitoring is required and dose adjustments are common.