How does nutritional status influence the development of pressure injuries?

How Nutritional Status Affects Pressure Injury Development

Malnutrition significantly increases the risk of developing pressure injuries by approximately 3.7-fold and is the most strongly associated modifiable risk factor for both pressure injury development and severity. 1

The Fundamental Relationship

Poor nutritional status creates a cascade of physiological vulnerabilities that directly compromise skin integrity and wound healing capacity. Malnutrition leads to:

• Protein loss and muscle wasting that reduces tissue padding over bony prominences
• Hypermetabolism and hypercatabolism that depletes nutrient reserves needed for tissue repair 2
• Micronutrient deficiencies (particularly conditionally essential amino acids and antioxidants) that are critical for all phases of wound healing 2
• Reduced tissue perfusion and oxygenation from decreased circulating proteins

The evidence is unequivocal: malnourished patients have 2.29 times higher odds of developing pressure injuries after adjusting for other risk factors 3, and malnutrition is also the strongest predictor of more severe pressure injuries (OR 1.88) 3.

Clinical Assessment Framework

Identifying At-Risk Patients

When evaluating pressure injury risk, nutritional assessment must be systematic:

1. Use validated screening tools: The Mini Nutritional Assessment (MNA) is validated, cost-effective, and can predict both malnutrition and pressure injury development 4. An MNA score <17 is an independent risk factor for pressure injury development 5.

2. Key biochemical markers to check:

   • Serum albumin (hypoalbuminemia strongly associated with pressure injuries) 5
   • Vitamin D levels (deficiency significantly more common in pressure injury patients) 5
   • Hemoglobin status

3. Anthropometric measurements: Low BMI is significantly associated with pressure injury development 5

Evidence-Based Nutritional Interventions

For Prevention

Standard nutritional supplementation (energy, protein, and micronutrients) may result in little to no difference in preventing pressure injuries compared to standard diet (RR 0.92,95% CI 0.71-1.19) 6. However, this low-certainty evidence should not discourage nutritional optimization, as the studies had methodological limitations.

More importantly, specific nutritional interventions reduce pressure injury incidence by 35% compared to standard nutrition (OR 1.35,95% CI 1.02-1.78) 1. The key is targeted intervention, not generic supplementation.

For Treatment of Existing Pressure Injuries

Energy, protein, and micronutrient supplements may slightly increase the number of healed pressure ulcers (RR 1.45,95% CI 1.14-1.85) 6. More specifically:

• Arginine/glutamine/β-HMB mixture shows significant effects: In polymorbid hospitalized patients, this combination (14g arginine, 14g glutamine, 2.4g calcium β-HMB daily) improved viable tissue by 43% vs 26% at two weeks (p=0.02) 2

• Collagen supplements probably improve pressure ulcer area reduction (MD 1.81 cm² smaller, 95% CI 3.36-0.26 smaller) 6

• Arginine with micronutrients may reduce pressure ulcer area by 15.8% (95% CI 25.11-6.48% lower) 6

Optimal Nutritional Targets

For patients with pressure injuries, provide:

• 30-35 kcal/kg body weight/day (adjusted for ulcer stage and hypermetabolic state)
• 1.2-2.0 g protein/kg body weight/day (higher end for more severe ulcers) 2
• Complete micronutrient supplementation including both multivitamins AND multi-trace elements, not vitamins alone 2

Critical Implementation Gaps

Current practice falls dangerously short of evidence-based care. In hospitalized older patients with pressure injuries 7:

• Only 25% were referred to a dietitian
• Only 18.3% received energy/protein-enriched diets
• Only 8.5% received oral nutritional supplements
• Only 39.4% had malnutrition screening performed

Healthcare professionals often lack knowledge about using nutritional screening tools to prompt dietitian referrals for high-risk patients 8, representing a critical barrier to implementing evidence-based prevention.

Practical Clinical Algorithm

1. Screen all patients with Braden Scale ≤18 for nutritional deficiency using MNA 4
2. If MNA <17: Implement immediate multicomponent nutrition intervention (this approach decreased pressure injury rates from 1.9% to 0.5%, a 74% reduction) 4
3. Ensure health professional assessment of nutritional status and dietary intake (reduces pressure injury odds by 57% and 53% respectively) 3
4. For existing pressure injuries: Provide hypermetabolic/hypercatabolic nutrition targets PLUS consider specialized supplements (arginine/glutamine/β-HMB or arginine with micronutrients) 2

Key Caveats

The evidence on specific nutrient compositions remains uncertain due to heterogeneity in study designs and formulations 6. However, the association between malnutrition and pressure injury development is consistent and strong across all studies. The uncertainty lies in which specific interventions work best, not whether nutrition matters—it unequivocally does.

Nutritional management has become more crucial as other risk factor management (like pressure redistribution) has improved 3, making it a priority intervention rather than an adjunct consideration.