Protein catabolic rate calculations in CAPD patients.

Four different approaches to calculating the protein catabolic rate (PCR, in g/kg/day) were investigated in 28 stable continuous ambulatory peritoneal dialysis (CAPD) patients and compared to the dietary protein intake (DPI) from a 3 day diet history. The modified Borah technique is based on the hemodialysis correlation, with the addition of measured effluent protein losses. The Randerson technique is a correlation similar to the Borah hemodialysis correlation, but it was established in a CAPD population. The Teehan technique estimates total nitrogen loss by adding the measured urea nitrogen loss to average values from the literature for protein, amino acid, and non-urea nitrogen losses. The Kjeldahl technique measures total nitrogen loss. All four techniques yielded similar PCR values (0.85-0.92 g/kg/day), none of which was significantly different from the DPI (0.89 g/kg/day). Based on the simplicity of the measurements and calculations, the Randerson technique is recommended for routine monitoring of PCR in CAPD patients.