How do I assess and diagnose malnutrition using the GLIM criteria?

How to Assess and Diagnose Malnutrition Using GLIM Criteria

Use the GLIM two-step approach: first screen all patients with a validated tool (NRS-2002 for hospitalized patients), then diagnose malnutrition by identifying at least one phenotypic criterion AND one etiologic criterion. 1

Step 1: Mandatory Nutritional Risk Screening

All patients in contact with health or elderly care must undergo nutritional risk screening as the first mandatory step before any malnutrition diagnosis can be made. 1, 2

Recommended Screening Tools by Population:

• Hospitalized patients (including surgical/critically ill): Use NRS-2002 3, 1
• Geriatric patients and polymorbid patients with cognitive dysfunction: Use Mini Nutritional Assessment Short-Form (MNA-SF) 1
• ICU patients: Use modified NUTRIC (mNUTRIC) score, which incorporates age, comorbidities, APACHE II, SOFA scores, and days in hospital before ICU admission 1
• General screening across body compositions: Use Malnutrition Screening Tool (MST) with 93-97% interrater reliability 1

Re-screen every 7-10 days during hospitalization. 1

Step 2: GLIM Diagnostic Criteria (Apply Only if Screening Positive)

Once screening identifies nutritional risk, diagnose malnutrition by documenting at least ONE phenotypic criterion AND at least ONE etiologic criterion. 3, 1

Phenotypic Criteria (Choose at least ONE):

1. Non-volitional weight loss:

• Moderate malnutrition (Stage 1): 5-10% within past 6 months OR 10-20% beyond 6 months 3
• Severe malnutrition (Stage 2): >10% within past 6 months OR >20% beyond 6 months 3

2. Low Body Mass Index (age-specific cutoffs):

• Moderate malnutrition (Stage 1):
  • <20 kg/m² if <70 years old
  • <22 kg/m² if ≥70 years old
  • Asia: <18.5 kg/m² if <70 years, <20 kg/m² if ≥70 years 3
• Severe malnutrition (Stage 2):
  • <18.5 kg/m² if <70 years old
  • <20 kg/m² if ≥70 years old 3

3. Reduced muscle mass (sex-specific):

• Moderate malnutrition (Stage 1): Mild to moderate deficit 3
• Severe malnutrition (Stage 2): Severe deficit 3
• Preferred measurement methods: DXA, BIA, CT, or MRI for fat-free mass index (FFMI) 4, 3
• Alternative methods when imaging unavailable: Physical examination, mid-arm muscle circumference, or calf circumference 4, 3
• FFMI cutoffs for severe malnutrition: <15 kg/m² in females, <17 kg/m² in males 2

Etiologic Criteria (Choose at least ONE):

1. Reduced food intake or assimilation:

• Moderate malnutrition (Stage 1): Any reduction below energy requirements for >2 weeks OR moderate malabsorption/GI symptoms 3
• Severe malnutrition (Stage 2): ≤50% of energy requirements for >1 week OR severe malabsorption/GI symptoms 3

2. Disease burden/inflammation:

• Acute disease/injury-related with inflammation 3
• Chronic disease-related 3

Critical Implementation Points

Common Pitfalls to Avoid:

Do not diagnose malnutrition without first completing validated screening—this is mandatory per GLIM criteria. 1, 2

Low BMI alone is insufficient for diagnosis; you must also document an etiologic factor. 4, 3 However, BMI <18.5 kg/m² can independently confirm malnutrition diagnosis per ESPEN alternative criteria. 5, 2

In ICU patients with generalized edema, physical examination for muscle and fat loss is challenging—consider imaging modalities (CT, MRI) when available. 4

In patients with obesity, do not assume malnutrition is absent—use the same GLIM criteria for screening and assessment. 1

Weight loss described as "non-volitional" may miss weight loss from unhealthy practices or secondary to acute illness. 4

Special Populations:

Kidney disease patients: GLIM criteria have not been validated; BMI may underestimate malnutrition due to fluid overload. 1

Patients with excess adiposity: Barriers exist to accurately assessing muscle or fat mass loss on physical examination. 4

Assessment Methods for Muscle Mass

Hierarchy of Measurement Techniques:

Preferred (most accurate):

• Dual-energy X-ray absorptiometry (DXA) 4, 3
• CT or MRI imaging 4, 3
• Bioelectrical impedance analysis (BIA) 4, 3

Alternative when preferred methods unavailable:

• Nutrition-Focused Physical Exam (NFPE) assessing subcutaneous fat loss, muscle mass loss, and edema 4, 1
• Mid-arm muscle circumference 4, 3
• Calf circumference 4, 3
• Handgrip strength as supportive functional measure 3

Note: NFPE requires training/expertise and may be more difficult without baseline comparison. 4

Complementary Assessment Tools

While GLIM is the international consensus standard, these tools provide additional clinical context:

Subjective Global Assessment (SGA): Validated tool incorporating weight change, dietary intake, GI symptoms, functional capacity, and physical findings—useful across settings including ICU with good predictivity for complications and mortality. 4, 1

ASPEN/Academy criteria: Requires at least 2 of 6 criteria (low energy intake, weight loss, loss of muscle mass, loss of subcutaneous fat, fluid accumulation, reduced handgrip strength). 4, 5

Monitoring Triggers

Initiate nutritional intervention when food intake ≤50% of energy requirements over 3 days during hospital stay. 1

Reassess nutritional status regularly during hospitalization, at discharge, and monitor weight, intake, functional status, and muscle mass throughout hospital stay. 1