Understanding the Malnutrition Universal Screening Tool (MUST)
Malnutrition is a state of nutrition where a deficiency or excess of nutrients negatively impacts health. It is a serious and often overlooked issue, particularly among hospitalized and older individuals. The Malnutrition Universal Screening Tool (MUST), developed by BAPEN, is a five-step tool for screening and managing malnutrition risk in adults across various healthcare settings. It helps identify individuals who are malnourished, at risk of undernutrition, or obese, allowing for appropriate care planning.
The Five Steps of the MUST Malnutrition Scale
The MUST tool comprises five steps. The first three steps gather information to determine a risk score in the fourth step, leading to a management plan in the fifth.
Step 1: Body Mass Index (BMI) Score
This step determines the patient's BMI and assigns a score. Height and weight are measured, or alternative methods like MUAC or reliable self-reported data are used if direct measurement is not possible.
- BMI > 20 kg/m² (>30 kg/m² for obese): 0 points
- BMI 18.5–20 kg/m²: 1 point
- BMI < 18.5 kg/m²: 2 points
Step 2: Unplanned Weight Loss Score
This step assesses unintentional weight loss over the past 3 to 6 months using historical or reported weight data.
- Unplanned weight loss <5%: 0 points
- Unplanned weight loss 5–10%: 1 point
- Unplanned weight loss >10%: 2 points
Step 3: Acute Disease Effect Score
This step considers if acute illness is likely to cause a lack of nutritional intake for over five days.
- No acute illness or nutritional intake >5 days: 0 points
- Acute illness with no intake >5 days: 2 points
Step 4: Overall Risk Score
The scores from the first three steps are added to determine the overall risk category.
Step 5: Clinical Management Guidelines
Based on the overall risk score, BAPEN provides guidelines for monitoring, nutritional support, and intervention.
Interpreting the MUST Score and Next Steps
The total MUST score determines the patient's risk category and subsequent actions.
- Score 0: Low Risk
- Routine clinical care and regular rescreening (frequency varies by setting).
- Score 1: Medium Risk
- Monitor food intake for three days. If intake is low, implement a plan to improve nutritional status and rescreen more often.
- Score ≥2: High Risk
- Begin immediate nutritional support, refer to a dietitian for a full assessment, and monitor closely.
Benefits and Limitations of the MUST Scale
Benefits
- Simple and practical for routine use.
- Applicable in various healthcare settings.
- Considers multiple factors (BMI, weight loss, acute disease).
- Can help predict negative clinical outcomes.
Limitations
- Not validated for children or pregnant women.
- Relies on obtaining accurate measurements.
- May not be sensitive enough to detect early malnutrition risk.
- Specificity may be lower in some populations.
Comparison of MUST with Other Screening Tools
| Feature | MUST | Mini Nutritional Assessment Short Form (MNA-SF) | Nutrition Risk Screening Tool (NRS-2002) |
|---|---|---|---|
| Target Population | All adults | Primarily older adults | Hospitalized patients |
| Key Assessment Criteria | BMI, Unplanned Weight Loss, Acute Disease Effect | BMI, Weight Loss, Appetite, Mobility, Psychological Stress, Neuro-psychological problems | BMI, Weight Loss, Reduced Food Intake, Severe Illness, Age |
| Number of Steps | 5 steps | 6 questions leading to a score out of 14 | Screening questions followed by a scoring process |
| Ease of Use | Simple, quick, and requires minimal training | Quick but may be less accurate if patient cannot provide reliable information | More detailed; includes disease and age modifiers |
| Predictive Validity | Predicts outcomes like hospital stay and mortality | Can be a strong predictor of outcomes in older adults | Validated for identifying patients who benefit from nutritional support |
| Setting | Hospital, community, care homes | Community and care homes | Primarily hospitals |
Conclusion
The MUST malnutrition scale remains a widely used screening tool for identifying adults at risk of malnutrition due to its simplicity and practicality. It systematically assesses BMI, unplanned weight loss, and the impact of acute disease to provide a crucial initial step in nutritional care. While it has limitations in detecting the earliest stages of malnutrition risk, its role in identifying patients requiring further assessment and intervention is well-established. By enabling proactive nutritional care, MUST helps improve patient outcomes and quality of care. A detailed explanatory booklet is available on the official BAPEN website.
