Adequacy of continuous ambulatory peritoneal dialysis: morbidity and mortality in chronic peritoneal dialysis

Mortality for hemodialysis patients tends to be in excess of 20% per year, and it is generally agreed that outcome for continuous ambulatory peritoneal dialysis patients is comparable. Several investigators have suggested recently that continuous ambulatory peritoneal dialysis, as commonly practiced, may not provide adequate therapy, especially for larger patients and for those with no residual renal function. Unfortunately, a dose-response curve relating the amount of dialysis delivered and clinical outcome for continuous ambulatory peritoneal dialysis patients has not been constructed. Several methods of quantifying the dose of peritoneal dialysis are described. Both cross-sectional and longitudinal studies are reviewed. The conclusions of these studies are of limited value, however, because of their retrospective nature and the limited number of patients enrolled. Nevertheless, in aggregate, these studies suggest that survival may be improved by higher doses of dialysis. They also suggest that while malnutrition is relatively common in this patient population, higher doses of Kt/V are associated with higher protein intake (as measured by protein catabolic rate). Serum albumin is recognized as a strong predictor of clinical outcome and the protein catabolic rate may correlate directly with Kt/V, but there are studies that support and others that refute a correlation between Kt/V and serum albumin. Definitive answers to these questions are likely to be available in the near future. Two large multicenter studies are currently under way. Preliminary results may be available in the near future.