The importance of early treatment of the anaemia of chronic kidney disease.

The beneficial effects of treating the anaemia of dialysis-dependent patients with erythropoietin on the improvement of cardiac status, exercise capacity, cognitive function and quality of life are well established. Equally, if not more important is the reduction in morbidity and mortality that accompanies the treatment of anaemia with epoietin. These documented improvements in outcomes of care notwithstanding, mortality and morbidity due to cardiovascular disease (CVD) remain high in dialysis patients. Recent epidemiological evidence indicates that: (i) the prevalence of CVD is very high in patients at the start of dialysis; (ii) pre-existing CVD is the major risk factor for mortality and morbidity on dialysis; (iii) CVD begins early in the course of kidney disease, shows an inverse relationship to kidney function and increases in prevalence and severity with progression of kidney disease; and (iv) corrective measures, which take 3-5 years to show a favourable effect, must be instituted well before the initiation of dialysis. Hypertension and anaemia, which develop in the course of progressive reduction in kidney function, are the principal risk factors for the prevalence of left ventricular hypertrophy (LVH) in those with chronic kidney disease, and their treatment has been shown to arrest or reverse LVH in these individuals. Whereas the treatment of hypertension early in the course of kidney disease has been incorporated into clinical practice, there has been reluctance in the treatment of anaemia because of the possibility of worsening kidney function with epoietin, as shown in rats. There is now convincing evidence that epoietin has no potential adverse effect on kidney function in humans. While the most compelling reason for the early treatment of the anaemia of kidney disease is its beneficial effect on cardiovascular function, other documented potential benefits are improvements in exercise capacity, cognitive function and quality of life.