Critical review of nutrition assessment tools to measure malnutrition in chronic kidney disease

The use of the Subjective Global Assessment (SGA) and similar clinical tools for nutrition assessment is integral in the nutritional management of chronic kidney disease (CKD) patients. The present paper is a critical review of the quality of studies introducing and validating SGA-based tools in CKD. In the CKD literature, clinical, predictive and criterion validity were investigated by a number of studies. Common limitations identified include the use of questionable statistical methods, difference in prevalence of malnutrition based on tool or administrator (i.e. dietitan, nephrologist or nurse) and use of inadequate reference tests to establish true nutrition status. The SGA appears to have the best diagnostic evidence to adequately detect the presence of abnormal nutrition status and prognostic evidence to predict poor outcome. Modified scored versions may improve clinician's ability to detect degree of malnutrition; however, the present review indicates more work is required. Tools based on the original SGA claiming validity in CKD and potentially other clinical areas should be approached with caution. Critical evaluation of study design, reference tests and statistical methods is recommended before implementing new tools in practice.