Significance of residual renal functions of patients with end-stage renal failure undergoing continuous ambulatory peritoneal dialysis

Abstract

It is generally accepted that residual renal function remains well-preserved longer with CAPD than with hemodialysis. However, consideration and impact of the contributory effects of residual renal function on the adequacy of renal replacement therapy has not been well defined. In this report, creatinine clearance (Ccr), Kt/V, normalized protein catabolic rate (nPCR) and urinary excretion of uremic solutes were studied in 26 stable CAPD patients with a four-bag exchange. Weekly Ccr, weekly Kt/V and nPCR were 62.3 +/- 20.2 l/week/1.73 m2, 1.77 +/- 0.35, and 0.90 +/- 0.13 g/kg/day, respectively. These parameters correlated significantly with the daily urine volume. The weekly Ccr and Kt/V of anuric patients seemed to be inadequate. Urinary excretion of urea nitrogen, Cr, Na, Cl, Pi and beta 2-microglobulin (beta 2-MG) were dependent upon the daily urine volume. Significant phosphorus and beta 2-MG excretion seemed to have an effect on the prevention of bone and joint complications, because serum iPTH and beta 2-MG levels increased after the patients fell into an anuric state. It was suggested from this study that CAPD should be started before the patient loses residual renal function because four bag exchange as the standard CAPD prescription might not be adequate once the patient loses urine excretion.