How can malnutrition be prevented or treated in older adults with polymorbidity, particularly those with multiple chronic conditions and impaired nutritional status?

Management of Malnutrition in Older Adults with Polymorbidity

All older adults with multiple chronic conditions should be screened for malnutrition risk at hospital admission using validated tools (NRS-2002 or MNA-SF), followed by immediate nutritional intervention for those at risk, as this approach reduces mortality, complications, and hospital readmissions. 1

Screening and Assessment

Use rapid, validated screening tools immediately upon hospital contact:

• Apply NRS-2002 for hospitalized polymorbid patients or MNA-SF for older adults, as both tools demonstrate high content validity and reliability even in patients with cognitive dysfunction 1
• Screen at admission, when clinical condition changes unexpectedly, and periodically during hospitalization 1
• Polymorbid medical inpatients have 40-50% prevalence of malnutrition in tertiary care centers, making universal screening essential 1

For patients screening positive, perform detailed assessment:

• Establish diagnosis using GLIM criteria (Global Leadership Initiative on Malnutrition), which requires both phenotypic criteria (weight loss, low BMI, reduced muscle mass) and etiologic criteria (reduced intake, inflammation, disease burden) 1
• Assess directly measured serum osmolality (>300 mOsm/kg indicates dehydration) to identify concurrent low-intake dehydration 1
• Do not rely on albumin alone as it is affected by inflammation and non-nutritional factors 2

Nutritional Targets and Interventions

Energy Requirements:

• Target 27 kcal/kg actual body weight/day for polymorbid older patients (≥65 years) 1
• For severely underweight patients, estimate 30 kcal/kg actual body weight, but increase gradually over first 72 hours to prevent refeeding syndrome 1, 2
• Monitor phosphate, magnesium, potassium, and thiamine during initial three days and supplement even for mild deficiencies 2

Protein Requirements:

• Provide 1.1-1.5 g protein/kg body weight/day as this is cost-effective and highly efficient to prevent weight loss, reduce complications, improve functional outcomes and quality of life 1
• Exception: For patients with eGFR <30 ml/min/1.73m² not on dialysis, restrict to 0.8 g protein/kg/day 1

Micronutrients:

• Ensure adequate intake of vitamins and trace elements to meet daily estimated requirements 1

Treatment Algorithm

Step 1: Oral Nutritional Interventions (First-Line)

• Begin with dietary counseling and food fortification to increase energy and protein density without increasing volume 2
• Offer small, frequent meals with additional snacks between main meals 2
• Provide mealtime assistance for patients with eating dependency 2
• Avoid restrictive diets as they worsen malnutrition and provide limited benefits 1, 2

Step 2: Oral Nutritional Supplements (ONS)

• When dietary counseling fails, prescribe high-protein ONS providing at least 400 kcal/day including ≥30g protein/day 2
• This intervention reduces mortality (OR 0.68; 95% CI 0.51-0.91) and hospital readmissions (OR 0.64; 95% CI 0.45-0.90) in polymorbid patients 1
• Target achieving 75% of estimated nutrition goals, as the EFFORT trial demonstrated this threshold significantly lowers adverse events and mortality compared to lower achievements 1

Step 3: Enteral Nutrition (EN)

• When oral intake cannot meet requirements, use EN before parenteral nutrition due to lower risk of infectious complications, non-infectious complications, and maintenance of gut integrity 1
• For older patients requiring EN, use formulas enriched with mixture of soluble and insoluble fibers (30g fiber: 33% insoluble, 67% soluble) to improve bowel function 1

Step 4: Parenteral Nutrition (PN)

• Reserve for patients whose nutritional requirements cannot be met through oral or enteral routes 1

Disease-Specific Considerations

Diabetes with Malnutrition:

• Follow same guidelines as non-diabetic older adults - prevention and treatment of malnutrition takes priority over possible long-term hyperglycemia complications 1, 2
• Use balanced diet with 50-55% energy from carbohydrates, rich in fiber (25-30 g/day), favoring mono- and polyunsaturated fatty acids 1
• ONS or EN may raise glucose levels, but this is acceptable given malnutrition's immediate negative outcomes 1

Pressure Ulcers:

• Consider supplementation with formulas enriched in arginine, zinc, and antioxidants, as one controlled trial showed improved healing compared to isocaloric isonitrogenous formula 1, 2

Cognitive Dysfunction:

• NRS-2002 and MNA-SF remain valid screening tools even with cognitive impairment 1

Post-Discharge Management

Continuation of nutritional support after hospital discharge is mandatory:

• Continue ONS or individualized nutritional intervention post-discharge to maintain or improve body weight, nutritional status, and lower mortality 1
• This is particularly critical for patients ≥65 years at high risk of malnutrition 1
• Establish organizational changes including nutritional multidisciplinary support teams and nutrition protocols to improve intake and outcomes 1

Monitoring

Track functional indices rather than solely nutritional parameters:

• Functional indices (mobility, activities of daily living, quality of life) are more appropriate for assessing clinical outcomes including survival in polymorbid patients 1
• Monitor for drug-drug and drug-nutrient interactions with pharmacist-assisted management plan 1

Critical Pitfalls to Avoid

Common errors that worsen outcomes:

• Never delay screening or intervention - malnourished patients have 2.38 times higher odds of length of stay ≥3 days and 2.28 times higher odds of 30-day readmission 1
• Do not use skin turgor, mouth dryness, weight change, urine color, or bioelectrical impedance to assess hydration status in older adults - these are unreliable 1
• Avoid restrictive diets that limit intake, as they can lead to nutrient deficiencies 1, 2
• Do not restrict energy intake even in obese malnourished patients 2

Evidence demonstrates early standardized nutritional intervention:

• Results in more pronounced weight gain (0.92 kg vs 0.76 kg, p<0.001) 1
• Significantly lowers nosocomial infections (23.6% vs 36.7%, p=0.01) 1
• Reduces overall complication rate (20.3% vs 28.1%, p=0.009), primarily infectious complications (10.5% vs 18.9%, p<0.001) 1