[When to start dialysis. The predialysis patient].G Ital Nefrol. 2008 May-Jun; 25 Suppl 41:S9-12, discussion S13-20.GI
The incidence and prevalence of chronic renal failure (CKD), defined according to the NFK-KDOQI guidelines as a glomerular filtration rate less than 60 mL/min/1.73 m2 or the presence of microalbuminuria, is increasing worldwide, leading to an increased risk of cardiovascular disease. There is general agreement about the importance of early referral to the nephrologist and predialysis educational programs because this strategy prevents the progression (by the use of renin-angiotensin system blockers, low-protein diet) and complications (arterial hypertension, anemia, malnutrition, osteodystrophy, acidosis) of renal disease. Predialysis education helps patients choose the renal replacement therapy modality (hemodialysis, peritoneal dialysis, transplantation) and improve their quality of life. Furthermore, adequate predialysis care allows the nephrologist to prepare the vascular access well in advance. In contrast to the wished-for practice of early referral, patients are often referred to the nephrologist when renal failure is already advanced. This is mainly due to the fact that non-nephrologists pay little attention to identifying patients at risk for renal failure or defining the degree of renal failure according to the KDOQI classification. In addition, serum creatinine alone provides no adequate estimate of renal function, and both the MDRD equation and the Cockcroft-Gault formula permit a more accurate estimation of the glomerular filtration rate (GFR). Using the MDRD equation, the KDOQI guidelines recommend referral when GFR is less than 30 mL/min/1.73 m2. Late nephrology referral is an independent risk factor for early death while on dialysis, as well as being associated with a more frequent use of temporary catheters, particularly in the elderly but also in patients receiving regular nephrology care. This underlines the importance of a multidisciplinary predialysis approach which may bring additional benefits - beyond referral to a nephrologists - including a reduced hospitalization rate and improved survival. The KDOQI guidelines recommend evaluating the benefits and risks of starting renal replacement therapy when patients reach stage 5 (estimated GFR <15 mL/min/1.73 m2), although the ideal time for replacement therapy initiation remains a matter of debate and the results of prospective clinical trials are awaited to resolve this issue.