Understanding the MUST Screening Tool
Developed by the British Association for Parenteral and Enteral Nutrition (BAPEN), the Malnutrition Universal Screening Tool ('MUST') is an effective, evidence-based approach to nutritional assessment. It is not just about identifying those who are already malnourished, but also those at risk of becoming so, as well as those who are obese. Its purpose is to standardise the assessment of nutritional risk, ensuring early identification and intervention to improve patient outcomes and reduce healthcare costs. The tool is widely applicable in hospitals, community settings, and care homes, and is designed to be used by all trained care workers.
The Five-Step Process of MUST
The tool's methodical approach ensures a consistent and comprehensive evaluation of an individual’s nutritional status. The five steps are as follows:
- Step 1: Calculate BMI Score. The patient's BMI is determined from their height and weight. If a patient's BMI is <18.5 kg/m², they score 2 points; between 18.5-20 kg/m², they score 1; and >20 kg/m² (>30 for obese) they score 0. Alternative measurements like mid upper arm circumference (MUAC) can be used if height and weight are unavailable.
- Step 2: Assess Unplanned Weight Loss. Healthcare providers inquire about and quantify any unintentional weight loss over the last 3-6 months. A loss of 5-10% scores 1, while a loss of >10% scores 2. A loss of <5% scores 0.
- Step 3: Establish Acute Disease Effect. This step considers the impact of acute illness on nutritional intake. If a patient is acutely ill and has had, or is likely to have, no nutritional intake for more than 5 days, they are given a score of 2.
- Step 4: Determine Overall Risk Score. The scores from steps 1, 2, and 3 are added together to produce an overall risk of malnutrition score. A score of 0 indicates low risk, 1 indicates medium risk, and 2 or more indicates high risk.
- Step 5: Implement Management Plan. Based on the total score, a management plan is developed using established guidelines and local policy. This may range from routine monitoring for low-risk patients to referral to a dietitian for those at high risk.
Why the MUST Screening Tool is Important
The significance of the MUST tool extends far beyond a simple calculation, profoundly influencing patient safety, care, and economic efficiency in healthcare.
Early Detection and Intervention
One of MUST's most critical benefits is its ability to facilitate early identification of malnutrition or risk thereof. By triggering intervention sooner, the tool can prevent a patient's nutritional status from deteriorating further. For instance, a patient identified as being at medium risk might have their dietary intake monitored, while a high-risk patient would be referred to a nutritional support team.
Predicting Patient Outcomes and Reducing Complications
Robust clinical evidence shows that MUST is effective in predicting patient outcomes. Studies have found a correlation between higher MUST scores and increased length of hospital stay, higher complication rates, and even increased mortality. A recent study involving cardiovascular surgery patients demonstrated that MUST was particularly effective in predicting postoperative ADL (Activities of Daily Living) decline. This predictive capability enables clinicians to take proactive steps to mitigate risks and improve recovery rates.
Universality and Accessibility
Unlike some other assessment tools, MUST is designed for universal application across a range of settings, including hospitals, community care, and care homes, and can be used by all trained staff. Its simple, quick, and low-cost nature means it can be implemented widely, ensuring that nutritional screening is a routine part of care, rather than an exception.
Standardizing Nutritional Care
The five-step, standardised approach promoted by MUST ensures consistency in nutritional assessments and care planning across different healthcare professionals and settings. This consistency helps to improve communication and continuity of care, ensuring that patients receive the appropriate nutritional support throughout their healthcare journey, from admission to discharge and beyond.
Cost-Effectiveness in Healthcare
Identifying and addressing malnutrition early is a cost-effective strategy. By improving patient outcomes, reducing complications, and shortening hospital stays, nutritional intervention can significantly lower overall healthcare costs. Preventing malnutrition is always more cost-effective than treating its consequences.
Comparison of MUST with Other Screening Tools
While several nutritional assessment tools exist, studies have highlighted the specific advantages of MUST in certain clinical contexts, particularly its effectiveness in predicting functional decline. One comparative study in cardiovascular surgery patients found significant differences in the ability of different tools to predict outcomes.
| Assessment Tool | Predicts Postoperative ADL Decline | Predicts Severe Complications | Key Features and Limitations |
|---|---|---|---|
| MUST | Yes (most effective) | Yes (significantly) | Simple, validated, and highly effective for predicting functional and clinical outcomes. May not be suitable for frailty screening alone. |
| MNA-SF | No (multivariate analysis) | Yes (univariate analysis) | Designed for elderly patients, but has low specificity. |
| GLIM | No | Yes | Accounts for decreased intake/absorption and inflammation, but less effective for predicting ADL decline in this specific context. |
| NRS-2002 | No (multivariate analysis) | Yes (univariate analysis) | Good for predicting complications and hospital stays, but intake criteria can be difficult for cardiac patients. |
Continued Nutritional Monitoring
It is crucial to remember that MUST is a screening tool, not a full diagnosis. It is the first step in a larger process of nutritional care. For medium and high-risk patients, continuous monitoring and review are necessary to ensure that interventions are effective and that nutritional status improves. Routine re-screening based on local policy is also essential for all patients, regardless of their initial score. The tool should be used alongside clinical judgment, especially for patients with complex conditions like terminal illness, where the focus may be on comfort rather than nutritional optimisation.
Conclusion
In summary, the MUST screening tool is an invaluable asset in modern healthcare. By providing a quick, easy, and validated method for identifying malnutrition risk, it empowers healthcare professionals to deliver more effective, proactive, and cost-efficient care. Its widespread application across different settings helps to standardise nutritional assessment, ensuring that at-risk patients receive the timely intervention they need to improve their recovery and overall quality of life. The evidence-based reliability of MUST makes it a cornerstone of good nutritional practice. For more detailed information, the BAPEN website provides a full explanatory booklet and resources.
