Evaluation of Nutrition Status Using the Subjective Global Assessment: Malnutrition, Cachexia, and Sarcopenia

Abstract The subjective global assessment (SGA) is a nutrition assessment tool that refers to an overall evaluation of a patient's history and physical examination and uses structured clinical parameters to diagnose malnutrition. The SGA is known to be a reliable and valid tool that predicts morbidity and mortality associated with malnutrition. The objective of SGA is to identify patients likely to benefit from nutrition intervention and therefore to identify persons in whom inadequate nutrition intake or absorption explain features of malnutrition, including body wasting. There are other conditions that cause weight loss, muscle wasting, and fat loss, including cachexia and sarcopenia. Acknowledging that these 2 last conditions differ in their mechanism of body wasting and consequently in the outcomes of nutrition intervention, the practitioner needs a tool to identify when malnutrition is the dominating factor to explain body wasting. The SGA form has been revised to clearly reflect the key concepts behind the diagnosis of malnutrition and help to distinguish this condition from other wasting conditions. This review presents the revised SGA form and guidance document. Using case studies, it illustrates the 3 wasting conditions, their overlap, and how the SGA identifies malnutrition as a dominating factor of body wasting and thus individuals who require nutrition intervention.