Middle molecule clearance does not influence protein intake in hemodialysis patients

Nutritional status in hemodialysis patients is a strong predictor of morbidity and mortality To isolate the impact of dialyzer flux on nutrition in hemodialysis patients, we compared the nutritional effect of high-flux dialysis with that low-flux dialysis, using a biocompatible membrane for both. Sixty-five patients were monitored for 8 months after changing to high-flux dialysis with a F80 polysulfone dialyzer following a 6-month baseline period of low-flux dialysis with a F8 polysulfone dialyzer, The Kt/V and normalized protein catabolic rate (nPCR) were the same on both the F8 and F80 dialyzers, The regression of nPCR versus KtN was also nearly identical, Despite the unchanged protein intake, the serum albumin (3.86 to 4.04 g/dL; P < 0.01) and serum creatinine (10.3 +/- 0.2 mg/dL to 11.2 +/- 0.3 mq/dL; P < 0.05) significantly increased during 8 months of high-flux dialysis. Therefore, we conclude that the increased removal of middle molecules by high-flux dialysis has no apparent effect on appetite as measured by nPCR, but it has a beneficial effect on serum albumin and serum creatinine, suggesting a role for middle molecules in the control of albumin and protein synthesis in the body. (C) 1998 by the National Kidney Foundation, Inc.