Assessment of body protein: energy status in chronic kidney disease

The prevalence of protein-energy malnutrition progressively increases during the evolution of chronic kidney disease (CKD). As a consequence, it has been reported that 40% of patients present with symptoms of undernutrition at the entrance to chronic dialysis treatment. In patients established on maintenance hemodialysis, the prevalence of malnutrition varies from 20% to 60% according to which indicators of nutritional status are used. Protein-energy malnutrition is associated with an increase in overall and cardiovascular death risks both in CKD patients not yet on dialysis and in dialysis patients. Given the impact of protein-energy wasting on the outcome of CKD patients, screening malnutrition and monitoring protein-energy status appear of primary importance. Therefore, scientific and professional societies or foundations have developed guidelines for the assessment of nutritional status as well as for the treatment of malnourished CKD patients. Recently, an expert panel recommended the term protein-energy wasting for loss of body protein mass and fuel reserves. According to these recommendations, protein-energy wasting should be diagnosed if 3 characteristics are present (low serum levels of albumin, transthyretin, or cholesterol), reduced body mass (low or reduced body mass or fat mass or weight loss with reduced intake of protein and energy), and reduced muscle mass (muscle wasting or sarcopenia, reduced mid-arm-muscle circumference). The present article addresses the methods for assessing protein-energy status, their specificities regarding the CKD staging, and the criteria for choosing among these methods when managing the follow-up evaluation of CKD patients. The practical implications of nutritional parameters for the management of CKD patients are illustrated by a case presentation.