Gastroenterology Topic

Hospital malnutrition.

Up to half of inpatients are malnourished and most are never diagnosed. Screen within 24h, diagnose with GLIM, and feed to target — one of the few inpatient interventions with a survival signal.

Reviewed June 2026 · verify against current guidelines

Why It Matters

Common, costly, invisible.

The scale

Up to half of hospital inpatients are malnourished, and about a third who arrive well-nourished decline during the stay.

Why it gets missed

Malnutrition independently raises mortality, length of stay, and readmission.
Step 1: Screen

Screen everyone, fast.

Within 24 hours

The Joint Commission requires nutrition screening within 24 h of admission. Use a validated tool, not a clinical hunch.

Validated screens

MSTRecent weight loss plus reduced intake. Two questions.
NRS-2002Nutrition status plus disease severity plus age. Inpatient standard.
MUSTBMI plus weight loss plus acute disease effect.
A positive screen triggers assessment, not treatment. Do not stop at the score.
MST Malnutrition Screening ToolNRS-2002 Nutritional Risk Screening 2002MUST Malnutrition Universal Screening Tool
Step 2: Diagnose

GLIM in one slide.

The rule

Diagnose malnutrition with at least one phenotypic criterion plus at least one etiologic criterion.

Phenotypic (need ≥1)

Weight loss>5% in 6 months, or >10% beyond 6 months
Low BMI<20 if age <70; <22 if age ≥70
Low muscle massBy exam or body composition (BIA, DXA)

Etiologic (need ≥1)

Reduced intake≤50% of needs >1 wk, any drop >2 wk, or malabsorption
InflammationAcute illness or injury, or chronic disease

Severity (moderate vs severe) is graded on the phenotypic criteria. Asia uses lower BMI cutoffs.

GLIM Global Leadership Initiative on MalnutritionBIA bioelectrical impedance analysisDXA dual-energy X-ray absorptiometry
Step 3: Act

Feed to a target.

Set the targets

Energy25-30 kcal/kg/day
Protein1.2-2.0 g/kg/day. The RDA's 0.8 is for the healthy.

The intervention

EFFORT (n=2,028): individualized feeding cut 30-day mortality to 7% vs 10% (OR 0.65).
RDA recommended dietary allowanceEFFORT Effect of early nutritional therapy trial
Step 4: Micronutrients

Test, replete, refeed safely.

Test and replete

Thiamine (B1)Empirically: alcohol use, bariatric, prolonged poor intake.
B12, folateMacrocytic anemia or neuro symptoms.
Vit D, iron, zincCommon deficits; read iron and zinc against inflammation.

Refeeding (NICE)

ElectrolytesPhosphate, K, Mg fall as feeding starts. Monitor and replete.
High riskStart ≤10 kcal/kg/day; build to full over 4-7 days.
Give thiamine before glucose or feeding in at-risk patients. Do not wait for a level.
NICE National Institute for Health and Care Excellence (UK)

Sources

Verify against current guidelines and local protocol before acting.

  1. Cederholm T, Jensen GL, Correia MITD, et al. GLIM criteria for the diagnosis of malnutrition: a consensus report. Clin Nutr 2019;38:1-9 (also JPEN 2019;43:32-40).
  2. Jensen GL, Cederholm T, et al. GLIM consensus approach to diagnosis of malnutrition: a 5-year update. JPEN / Clin Nutr 2025.
  3. Schuetz P, Fehr R, Baechli V, et al. Individualised nutritional support in medical inpatients at nutritional risk (EFFORT). Lancet 2019;393:2312-2321.
  4. ESPEN guideline on nutritional support for polymorbid medical inpatients. Clin Nutr 2023.
  5. Evans DC, et al. Use of visceral proteins as nutrition markers: ASPEN position paper. Nutr Clin Pract 2021 (albumin/prealbumin reflect inflammation, not nutrition).
  6. NICE CG32. Nutrition support for adults: refeeding risk (high-risk start ≤10 kcal/kg/day; thiamine plus electrolytes).
  7. The Joint Commission: nutrition screening required within 24 h of admission.

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Hospital malnutrition.
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