Identification and assessment of the malnourished patient

The assessment of protein-energy malnutrition has become important for identifying patients whose nutritional status increases their risk of an adverse outcome during hospitalization. Anthropometric, biochemical and immunological measurements, used either alone or in combination are not sensitive or specific enough for monitoring short-term nutritional changes, although some of these variables are associated with an increased incidence of postoperative complications after surgical procedures. The sensitivity of clinical assessment is dependent on the training of the clinician and the outcome variable being sought. For most clinicians, objective measurements are needed to raise their awareness to potential nutritional problems. The relationship of nutritional status to clinical events, particularly stress events during hospitalization, is critical to the interpretation of nutritional measurements and relating them to outcome variables. A classification based on the concepts of nutritional depletion and stress is presented. The prevalence of PEM has been shown to be between 20 and 30% in western hospitals, depending on the population studied and the criteria used to define PEM. In studies which have claimed an association between nutritional status and outcome, the contribution of nutritional variables to the development of postoperative complications has been overestimated and the relevance of technical factors underestimated.