Does delirium cause anorexia (loss of appetite) in older hospitalized patients?

Does Delirium Cause Loss of Appetite?

Yes, delirium is directly associated with poor nutritional intake and loss of appetite in older hospitalized patients, though the relationship is bidirectional—malnutrition both contributes to delirium development and results from it. 1

The Bidirectional Relationship

Malnutrition as a Cause of Delirium

• Malnutrition is a common contributing factor to delirium development, with 75% of patients with delirium suffering from malnutrition, indicating that poor nutritional status plays a significant role in precipitating delirium. 2
• Malnutrition serves as an independent risk factor for incident delirium, with malnourished older adults having twice the odds (OR 2.00,95% CI 1.08-3.72) of developing delirium compared to well-nourished individuals. 3
• The brain has high nutritional requirements, making it particularly vulnerable to cognitive dysfunction including delirium when nutritional status is compromised. 2

Delirium as a Cause of Poor Intake

• Hospitalized older patients with present delirium must be screened for malnutrition as both a potential cause AND consequence of delirium, recognizing that delirium itself impairs the ability to eat adequately. 1
• Hypoactive delirium—the most commonly missed subtype—presents with reduced psychomotor activity, lethargy, and decreased flow of speech, all of which directly interfere with eating and drinking. 4
• The altered level of consciousness and reduced awareness of surroundings that characterize delirium make patients unable to recognize hunger cues or respond appropriately to meals. 1

Clinical Implications for Management

Screening Requirements

• All older patients admitted to medical wards who are at moderate to high risk of delirium must receive multi-component non-pharmacological interventions that include hydration and nutrition management. 1
• Dehydration is a common precipitating factor for delirium and must be addressed immediately upon recognition. 1

Intervention Strategies

• Multi-component interventions that include nutrition support have proven efficacy in preventing delirium (Grade A recommendation), though nutrition as a single intervention has not been studied in isolation. 1
• Specific strategies include: encouraging patients to drink when they can swallow safely, assisting patients at mealtimes, providing hydration assistance by keeping water close by, and offering personal help when needed. 1
• Early mobilization and avoiding physical restraints help maintain functional capacity for eating. 1

Critical Prognostic Information

Patients suffering from both malnutrition and delirium have dramatically worse outcomes: 4 times higher mortality at one month, 7 times increased rate of discharge to nursing homes, and 3 additional days of hospitalization compared to those with neither condition. 2

Common Pitfalls to Avoid

• Do not attribute poor intake in delirious patients solely to the delirium without investigating and treating underlying malnutrition—both conditions require simultaneous attention. 1
• Hypoactive delirium is frequently missed because patients appear quiet and withdrawn rather than agitated, yet these patients are at highest risk for inadequate nutritional intake and carry higher mortality than hyperactive delirium. 4
• Close follow-up must occur to ensure adequate nutrition during and after delirium episodes, as nutritional interventions show efficacy only as long as they are continued. 2