What are the guidelines and interventions for patients identified as being at risk of malnutrition based on the Global Leadership Initiative on Malnutrition (GLIM) criteria?

GLIM Criteria for Malnutrition Diagnosis

What Are the GLIM Criteria?

The Global Leadership Initiative on Malnutrition (GLIM) criteria represent the international consensus framework for diagnosing malnutrition in adults across clinical settings, requiring a mandatory two-step approach: first, screening with validated tools (NRS-2002, MUST, or MNA-SF), followed by diagnostic assessment using at least one phenotypic criterion AND one etiologic criterion. 1, 2

The Two-Step Diagnostic Process

Step 1: Screening for Nutritional Risk

• All hospitalized patients must undergo nutritional risk screening using validated tools 1, 3
• For hospitalized patients, use NRS-2002 as the primary screening tool 1
• For geriatric patients, use MNA-SF which has high validity and reliability in this population 1
• For general medical patients, MUST is acceptable as an alternative screening method 1

Step 2: Diagnostic Assessment (GLIM Criteria)

To diagnose malnutrition, you must identify at least ONE phenotypic criterion AND at least ONE etiologic criterion 1, 2

Phenotypic Criteria (Choose ≥1):

1. Non-volitional weight loss - documented unintentional weight loss over time 1, 2
2. Low BMI - <20 kg/m² if <70 years old OR <22 kg/m² if ≥70 years old 1
3. Reduced muscle mass - assessed by DEXA, BIA, CT, MRI, or when unavailable, by physical examination or anthropometric measures (mid-arm muscle circumference, calf circumference) 1

Etiologic Criteria (Choose ≥1):

1. Reduced food intake or assimilation - inadequate nutrient intake or absorption 1, 2
2. Disease burden/inflammation - acute illness or chronic disease-related inflammation 1, 2

Severity Grading

GLIM provides two stages of malnutrition severity based on phenotypic metrics 2:

• Stage 1 (Moderate malnutrition) - meets minimum criteria thresholds
• Stage 2 (Severe malnutrition) - meets more advanced phenotypic criteria thresholds

Guidelines for Patients Identified at Risk

Immediate Interventions for At-Risk Patients

For non-critically ill hospitalized patients at nutritional risk who cannot meet requirements with regular diet alone, oral nutritional supplements (ONS) shall be offered immediately 1

• ONS should provide 10-12 kcal/kg and 0.3-0.5 g protein/kg daily when given twice daily at least 1 hour after meals 1
• Combine ONS with dietary counseling from registered dietitians or clinical nutritionists 1
• Monitor food intake closely - if intake falls to ≤50% of energy requirements for 3 days, escalate nutritional intervention 3

Developing the Treatment Plan

Once malnutrition is diagnosed, develop a detailed treatment plan that addresses the specific etiologic factors identified 1, 2:

• For reduced intake: Implement dietary counseling, modify food texture, address symptoms impairing intake (nausea, dysphagia), provide high-energy/high-protein menu options 1
• For inflammation/disease burden: Treat underlying conditions, manage metabolic stress, consider anti-inflammatory nutritional strategies 2
• For assimilation problems: Address malabsorption, optimize gut function, consider alternative feeding routes if needed 2

Monitoring and Reassessment

Reassess nutritional status regularly during hospitalization and at discharge 1:

• Monitor weight, intake, and functional status throughout hospital stay 1
• Reassess muscle mass using available methods 1
• Ensure handover to community services with ongoing dietary counseling for high-risk, frail, sarcopenic, or post-ICU patients 1

Critical Pitfalls and Special Considerations

Limitations in Specific Populations

In patients with kidney disease (AKI/CKD), GLIM criteria have NOT been validated, and BMI may underestimate malnutrition due to fluid overload 1. Despite this limitation, ESPEN recommends using GLIM with special attention to the BMI criterion in overhydrated patients 1.

In patients with obesity, do not assume adequate nutrition - screen and assess using the same GLIM criteria, as malnutrition is defined by inability to preserve healthy body composition and muscle mass, not just low body mass 1

In ICU patients with generalized edema, physical examination for muscle and fat loss becomes more challenging 1. Consider using imaging modalities (CT, MRI) when feasible, though these may not be practical for many ICU patients 1.

Common Assessment Challenges

Weight loss must be "non-volitional" - intentional weight loss achieved through unhealthy practices or secondary to acute illness may not be captured by GLIM criteria 1

Low BMI is frequently the most commonly used criterion 1, which may limit utility in patients with obesity or fluid overload 1

Muscle mass assessment requires expertise - preferred methods (DEXA, CT, MRI) may not be feasible in many settings 1. When unavailable, use physical examination or anthropometric measures, recognizing that excess adiposity presents barriers to accurate assessment 1

Documentation and Coding

Proper documentation of malnutrition diagnoses using ICD coding significantly affects hospital reimbursements 3. Ensure malnutrition is appropriately identified, diagnosed, and coded 3.

Validation Status

GLIM criteria require ongoing validation and reliability testing across different populations and healthcare settings 4, 2. Current evidence shows:

• Fair to good sensitivity (61-100%) and specificity (89-98%) when compared to Subjective Global Assessment 5, 6
• Prevalence of malnutrition by GLIM ranges from 16-80% depending on population and setting 6
• Best criterion combinations are weight loss + high CRP or weight loss + low intake, both with high specificity but variable sensitivity 5