NUTRITION AND MORTALITY IN HEMODIALYSIS

Protein-energy malnutrition is present in a large proportion of mainte nance hemodialysis (HD) patients, and it is associated with increased morbidity and mortality. The protein requirements are increased becaus e of the presence of endocrine and metabolic factors related to loss o f renal function, the HD procedure, and comorbidity factors, which all stimulate net protein catabolism. The intake protein and energy are f requently reduced because of the underlying disease, psychosocial fact ors, and uremic anorexia. However, the extent to which underdialysis c ontributes to anorexia and malnutrition is still not well defined. Mal nutrition is generally not recognized as a common direct cause of deat h as reflected in health statistics, except in the highest age groups. Anthropometric and biochemical signs of malnutrition are associated w ith increased mortality. A low serum albumin level is a strong predict ive risk factor that may reflect not only or mainly protein malnutriti on but also the influence of several other morbidity factors (overhydr ation, infection, chronic disease and others) that may entail an incre ased risk of death. Low levels of serum creatinine (low muscle mass), serum cholesterol (energy depletion), and BUN and low urea appearance rate (low protein intake) are also correlated to increased mortality. For the prevention and treatment of HD-associated malnutrition, measur es should be taken to correct factors that may suppress appetite and i ncrease net protein catabolism (underdialysis, acidosis, low energy in take, comorbid conditions, psychosocial and economic factors). Dietary advice should be given with the aim of ensuring an adequate intake of protein- and energy-giving products. Intradialytic parenteral nutriti on may have positive effects on nutritional status when other measures fail. However, the indications for such treatment have not yet been w ell defined, and the effects on survival, morbidity, and quality of li fe are not sufficiently well proved. More and better data, generated i n prospective, well-controlled studies, are obviously needed before in tradialytic parenteral nutrition can be generally recommended as thera py for malnourished HD patients.