Elsevier

Nutrition

Volume 15, Issue 6, June 1999, Pages 458-464
Nutrition

Original Articles
Development of a valid and reliable malnutrition screening tool for adult acute hospital patients

https://doi.org/10.1016/S0899-9007(99)00084-2Get rights and content

Abstract

Nutrition screening identifies individuals who are malnourished or at risk of becoming malnourished and who may benefit from nutrition support. The aim of this study was to develop a simple, reliable and valid malnutrition screening tool that could be used at hospital admission to identify adult acute patients at risk of malnutrition. The sample population included 408 patients admitted to an Australian hospital, excluding pediatric, maternity, and psychiatric patients. The ability of various nutrition screening questions to predict subjective global assessment (SGA) were examined in contingency tables. The combination of nutrition screening questions with the highest sensitivity and specificity at predicting SGA was termed the malnutrition screening tool (MST), and consisted of two questions regarding appetite and recent unintentional weight loss. Subjects who were at risk of malnutrition according to the MST had significantly lower mean values for the objective nutrition parameters (except immunologic parameters) and longer length of stays than subjects who were not at risk of malnutrition. Therefore convergent and predictive validity of the MST was established. The interrater reliability of the malnutrition screening tool was high (93–97%). The MST is a simple, quick, valid, and reliable tool which can be used to identify patients at risk of malnutrition.

Introduction

“Nutrition screening is the process of identifying parameters known to be associated with nutritional problems.”1 The purpose of nutrition screening is to identify individuals who are malnourished or at risk of becoming malnourished and who may benefit from nutrition support.1, 2, 3, 4 In the absence of nutrition screening, patients with malnutrition may remain unrecognized.

Nutrition assessment methods such as subjective global assessment are too detailed and time consuming to complete on all patients admitted to hospital, therefore nutrition screening is a feasible alternative for identifying patients at risk of malnutrition. Numerous nutrition screening tools have been developed to identify hospital patients at risk of malnutrition.2, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16 Many of the published nutrition screening tools have one or more of the following limitations: 1) their effectiveness, in terms of sensitivity, specificity, validity, reliability, and cost effectiveness have not been well established; 2) the screening parameters included have been based on clinical judgment and intuition; 3) they were developed in specific patient populations; 4) no practical information on how to implement them has been provided; 5) they may be complicated, time intensive, and invasive; 6) dietitians are often required to collect the data, which are therefore too specialized for implementation on a hospital-wide basis by nursing or administration staff; and 7) they use nutrition parameters that are not routinely or immediately available.4, 16

Few published nutrition screening tools have demonstrated their reliability and validity. Only three studies could be identified that have established the reliability and validity of their nutrition screening tools.13, 15, 16 However, these tools were complicated, time consuming, and required a health professional to perform calculations (for example to determine body mass index or percentage weight loss) and identify stress factors or diagnoses.

Recent studies have moved away from complex nutrition screening tools towards those containing two or three simple questions.17, 18, 19 These studies demonstrated that the simpler tools were as accurate at detecting nutritional risk, while reducing the time and cost involved. However, these tools were not assessed for reliability and validity.

As no quick, simple, reliable, and valid nutrition screening tool could be located in the published literature, the objective of this study was to develop a simple, reliable, and valid malnutrition screening tool that could be used to identify acutely ill adult patients at risk of malnutrition upon admission to hospital.

Section snippets

Selection/development of nutrition screening questions

Criteria for development of the malnutrition screening tool included that it 1) be applicable for use in a heterogeneous adult patient population; 2) use routinely available data; 3) be convenient to use, therefore simple, quick, and easily completed by non-professional staff, patient, or family; 4) be non-invasive and inexpensive; and 5) be valid and reproducible.1, 13 Therefore, anthropometric and biochemical data were not considered. Parameters requiring calculations, such as body mass index

Development of the malnutrition screening tool

The nutrition screening questions were tested individually against SGA for possible associations using the chi-square test (Table III ). Screening questions that had a sensitivity or specificity greater than 90% were identified (Table III). Several combinations of these screening questions were compared with SGA in contingency tables. The combination that resulted in the highest sensitivity and specificity included the questions “Have you been eating poorly because of a decreased appetite?” and

Development of the malnutrition screening tool

The MST is a simple, quick, valid, and reliable tool which can be used to identify patients at risk of malnutrition. The sensitivity and specificity of the malnutrition screening tool was 93%. The sensitivity of the MST is higher than that of previously published nutrition screening tools,13, 15, 16 although the ideal screening tool would be 100% sensitive and specific. As this is generally not achievable, the need to correctly classify all patients who are malnourished (sensitivity) takes

Summary

The MST is a simple, quick, reliable, valid, tool which can be completed by medical, nursing, dietetic, or administrative staff, as well as by family, friends, or the patients themselves on admission to hospital. Its high sensitivity and specificity indicates that it strongly predicts nutritional status as defined by SGA. Hence, the MST will consistently identify those patients at risk of malnutrition so that nutrition care can be initiated promptly.

Acknowledgements

This research was supported by a scholarship from Queensland University of Technology and Spotless Services Limited. The authors would like to thank the staff and patients of The Wesley Hospital.

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