Physical methods for evaluating the nutrition status of hemodialysis patients

This article aims to provide an overview of the different nutritional markers and the available methodologies for the physical assessment of nutrition status in hemodialysis patients, with special emphasis on early detection of protein energy wasting (PEW). Nutrition status assessment is made on the basis of anamnesis, physical examination, evaluation of nutrient intake, and on a selection of various screening/diagnostic methodologies. These methodologies can be subjective, e.g. the Subjective Global Assessment score (SGA), or objective in nature (e.g. bioimpedance analysis). In addition, certain biochemical tests may be employed (e.g. albumin, pre-albumin). The various subjective-based and objective methodologies provide different insights for the assessment of PEW, particularly regarding their propensity to differentiate between the important body composition compartments-fluid overload, fat mass and muscle mass. This review of currently available methods showed that no single approach and no single marker is able to detect alterations in nutrition status in a timely fashion and to follow such changes over time. The most clinically relevant approach presently appears to be the combination of the SGA method with the bioimpedance spectroscopy technique with physiological model and, additionally, laboratory tests for the detection of micro-nutrient deficiency.