Nutrition in daily hemodialysis

Reports of improved patient outcomes using very long hemodialysis sessions have rekindled interest in alternatives to the standard thrice weekly hemodialysis regimen.

A review of the current literature was undertaken to determine the effect of daily hemodialysis on nutritional indices. Several regimens that deliver longer treatments were considered, including thrice weekly dialysis for 6 to 8 hours, short daily hemodialysis (5 to 7 times per week) for 1.5 to 2.5 hours, and nocturnal hemodialysis for 6 to 8 hours. An increasing number of centers are experimenting with the latter 2 treatment schedules the results of which are reported herein.

Nutritional status is an important predictor of outcome in end-stage renal disease (ESRD) patients. Nutritional status of patients can be improved by increasing the dose of conventional hemodialysis or by using biocompatible membranes. Therefore, it should not be surprising that daily hemodialysis treatments may affect nutrition. Beyond the effect that the enhanced clearance of small-molecular-weight substances may have on nutrition, the daily modalities open another dimension of depuration because of the ability to remove larger-molecular-weight substances to an extent that has never been approached by conventional hemodialysis.

The preliminary data from the studies evaluating the influence of daily and nocturnal hemodialysis on nutrition status suggest a beneficial effect. In particular, a striking lowering of phosphorus level occurs with nocturnal hemodialysis. However, there is little prospective and randomized information on the effects of the modalities on incident patients. The number of patients enrolled in daily hemodialysis is only in the hundreds. Prospective clinical trials are required to delineate the full potential of these therapies as well the differences between them. Both daily and nocturnal regimens should be explored in future studies.