Can Malnutrition be Prevented? Nutrition and Dialysis Adequacy

As chronic renal failure (CRF) worsens, the nutritional balance is disrupt ed at several different levels that are normally responsible for maintaining metabolic homeostasis (1–3). These abnormalities may remain constant, improve, or worsen once dialysis is initiated. The success of dialytic intervention in correcting these abnormalities depends not only on the actual dose of delivered therapy, but also on the availability of nutrient substrate and the ease of modulating body composition.

In the general population body composition has long been used as a predictor for mortality (4). Several different approaches have been taken to identify individuals at risk for a poor outcome (5). These techniques may examine specific serological parameters or actual components of body composition thought to more precisely depict nutritional balance.

Historically, many reports have stressed the link between serum albumin levels and patient survival for both hemodialysis and peritoneal dialysis (6–11). However, some authors have questioned the usefulness of this marker (12–14). Based on these concerns, defining nutritional status through body composition measurements may offer a more meaningful assessment than standard serological parameters. Furthermore, in the setting of uremia the ability to successfully modulate body composition may denote the essence of what aptimal dialysis should signify. Conceptually, optimal dialysis represents the therapeutic return of an individual to nutritional balance, with an expected survival comparable to that of age, gender, and disease-matched nonuremic individuals. Because of the complexity of maintaining nutrient balance, the definition of adequate dialysis should be re-evaluated. Contemporary dialysis practice should extend beyond solely quantitating dialysis to include an understanding of nutrient balance, regulation of food intake, and the application of surveillance tools for identifying abnormalities in body composition. Only through expanding the end points of adequate dialysis can we move closer to optimal dialysis synonymous with long-term treatment survival.