Defining malnutrition: mission or mission impossible?

Objective: Although screening for malnutrition in health care has expanded enormously, a gold standard for the optimal definition and operationalism of malnutrition is still lacking. This report reflects expert opinions on the elements of the definition and operationalism of malnutrition and is meant to trigger further debate within the nutritional societies.

Methods: A Delphi study was performed consisting of three phases. After a literature review (phase 1), questions for a semistructured interviews (phase 2) were formulated. Subsequently, the results of these semistructured interviews were used to develop the final list of elements (for defining and operationalism of malnutrition). In phase 3 (final phase), experts were asked to provide written feedback regarding the ranking of elements concerning the importance of these elements.

Results: Twenty-two experts (response 73.3%) were included in the final phase of this Delphi study. No overall agreement could be reached. The elements deficiencies of energy or protein and decrease in fat-free mass were most often mentioned to be particularly important in defining malnutrition. Elements mentioned to be important in operationalism of malnutrition were involuntary weight loss, body mass index, and no nutritional intake. Opinions on cutoff points regarding these elements differed strongly among experts.

Conclusion: This study shows that there is no full agreement among experts on the elements defining and operationalism of malnutrition. The results of this study may fuel the discussion within the nutritional societies, which will most ideally lead to an international consensus on a definition and operationalism of malnutrition.