PROTEIN CATABOLISM DURING HEMODIALYSIS

Losses of both glucose and amino acids during dialysis therapy have been reported to induce significant protein catabolism. With the aid of urea kinetics both the extent of dialysis-induced catabolism and the potential effectiveness of using glucose to reduce on-dialysis catabolism have been examined. Dialysis against glucose-free dialysate increased protein catabolism (a mean of 27% in 10 patients) above off-dialysis levels, and this was accompanied by a fall in blood glucose (mean 1.7 mmole/liter in five patients) between predialysis and postdialysis. Addition of glucose to dialysate eliminated the fall in blood glucose in most patients and effected a subjective improvement postdialysis in patient well-being. This was not, however, accompanied by a significant fall in on-dialysis protein catabolic rate, suggesting that gluconeogenesis is not the major contributor to increased catabolism on-dialysis. A discrepancy between protein catabolic rate and dietary protein intake, together with a reduced rate of glucose production, was also observed in some patients. These patients were found to have very low caloric intakes (~1100 kcal/24° per 1.73 sq m body surface area BSA)) suggesting that protein catabolism was induced to supply energy. These data indicate the usefulness of urea kinetic analysis to examine patient nutritional status and emphasize the potential for solute kinetic analysis in elucidating the adequacy of dialysis therapy. Further, even though glucose did not produce the expected lowering of protein catabolism, its addition to dialysate is recommended because of reduced postdialysis fatigue and less symptomatic fluid removal.