Anaemia and chronic renal failure

Anaemia is a common complication of chronic kidney disease. Of the various contributory factors, the most important is an inappropriately low circulating concentration of erythropoietin, a hormone largely produced by the peritubular cells of the kidney. Chronic anaemia, particularly if severe, causes debilitating symptoms including tiredness and lethargy, muscle fatigue, reduced exercise capacity and breathlessness on exertion. There are adverse consequences for a number of physiological systems, particularly those of the heart and brain. The anaemia of kidney disease tends to develop once the glomerular filtration rate falls below 60 ml/min, and anaemic patients with a lesser degree of renal impairment should be screened carefully for another cause of anaemia. Synthetic erythropoietin therapy has transformed the management of renal anaemia; it induces an increase in haemoglobin concentration and prevents the need for repeated blood transfusions, particularly in dialysis patients. Many patients given erythropoietin therapy will require supplemental iron, and this is often given intravenously. Several new strategies for stimulating erythropoiesis are currently in development, including prolyl hydroxylase inhibition (HIF stabilizers), erythropoietin gene therapy, and modulation of hepcidin activity.