What do screening tools measure? Lessons learned from SCREEN II and SNAQ⁶⁵⁺

Summary

Background

Over the last decade, different screening tools for malnutrition have been developed. Within these tools, a distinction can be made between tools that assess nutritional risk and tools that assess protein energy malnutrition. Insights in differences in characteristics of participants at risk and in differences in prevalence rates will aid in deciding which tool(s) to use in daily practice.

Methods

Dutch community-dwelling older adults (n = 200, 78.2 ± 6.9 years), not known to have specific nutrition problems, were recruited to participate in this cross-sectional study. SNAQ⁶⁵⁺ (low risk vs moderate/high risk) was used to assess risk of protein energy malnutrition and SCREEN II was used to assess nutrition risk (score <54 out of 64). Chi-square tests were used to test associations between demographic, health, physical and social factors and outcome of SNAQ⁶⁵⁺ and SCREEN II.

Results

Of all participants 69.0% were at nutrition risk (SCREEN II), while 13.5% were at risk of protein energy malnutrition (SNAQ⁶⁵⁺). Agreement between the two tools was poor (kappa < 0.20). Gender, BMI, living status, income, activity level and protein/energy intake were associated with SCREEN II; age, BMI, comorbidities, medication use, help at home, activity level and low basic mobility were associated with SNAQ⁶⁵⁺.

Conclusion

SCREEN II and SNAQ⁶⁵⁺ measure different concepts of malnutrition and therefore identify different persons at risk. SCREEN II is more inclusive and comprises both undernutrition and overnutrition as well as different determinants that can impact on food intake, while SNAQ⁶⁵⁺ is solely focused on protein-energy malnutrition.

Introduction

As the older adult population in Western Europe grows [1], health care costs to support their health and wellbeing also increase [2,3]. To reduce these increasing costs, government policies are focusing on ways to support older adults to live healthy and independently for as long as possible [4]. Because malnutrition is associated with increased morbidity and institutionalization [5], early identification of community-dwelling older adults with nutrition risk is of major interest, especially in primary care. Screening for risk may be a first step to identify older adults who are prone to become malnourished in the future [6].

Most malnutrition screening tools, often based on recent weight loss, low BMI, presence of disease and/or low appetite) [7], are designed, at least initially, for use in hospitals and aim at identifying persons with already existing malnutrition [8]. Thus, they measure mostly ‘the late phase’ where signs of merely protein energy malnutrition (e.g. unintentional weight loss and loss of muscle mass) are already present [9]. Fewer tools have been developed for the community setting. SNAQ⁶⁵⁺ and SCREEN II are two malnutrition screening tools validated for use in community dwelling older adults [8]. Despite both being called ‘malnutrition screening tools’, these tools may not be interchangeable. SCREEN II was originally designed as a nutrition risk screening tool and identifies risk factors, including determinants of food intake, that can lead to inadequate food intake and eventual malnutrition in community-dwelling older adults if no interventions are put into place. It also determines weight change (both gain and loss) and the intentionality of this change [10]. In contrast, SNAQ⁶⁵⁺ identifies common indicators of protein energy malnutrition, and specifically, involuntary weight loss, low upper arm circumference, loss of appetite and inability to walk stairs, which may indicate that a person is already experiencing malnutrition [11].

Power et al., in their systematic review (8) briefly mention the different aims of malnutrition screening tools (a poor nutrition status or protein energy malnutrition), but do not discuss the potential differences in prevalence rates that are expected when using different tools, which is a factor in the decision to use a tool. Comparing prevalence rates using different tools within one population [12], and examining differences in characteristics of those identified at risk would be a first step to understanding which tool, for which purposes, may be most useful in primary care. This study aims to determine: a) risk prevalence rates according to SCREEN II and SNAQ⁶⁵⁺, b) the association between risk and participants' demographic, health, physical, functional and social factors, and c) the agreement between risk as measured by SCREEN II and SNAQ⁶⁵⁺. Based on these results, we will consequently discuss how different screening tools can exist, and even complement each other, and how they can be deployed in primary care.