What are the potential causes and treatment options for loss of appetite in an older adult with a history of chronic illnesses?

Loss of Appetite in Older Adults with Chronic Illnesses

In older adults with chronic illnesses and loss of appetite, you must first conduct a systematic cause-oriented assessment to identify and treat reversible factors—particularly medication side effects, pain, depression, dental problems, and social isolation—before considering pharmacological appetite stimulants, which should be reserved for patients with concurrent depression (mirtazapine) or those with months-to-weeks life expectancy where quality of life is the priority. 1

Systematic Assessment of Reversible Causes

The most critical first step is identifying treatable causes of appetite loss, as these are often easier to address than dementia-specific changes and can significantly improve outcomes. 1

Medication Review (Highest Priority)

• Polypharmacy is robustly associated with malnutrition in older adults and should be your first target. 1
• Medications commonly causing appetite loss include:
  • Opioids, sedatives, digoxin, metformin, antibiotics, and NSAIDs 1
  • Cholinesterase inhibitors (in dementia patients) can cause weight loss in vulnerable individuals 1
• Assess the temporal relationship between medication changes and appetite/weight changes. 1
• Reduce or replace medications causing xerostomia, nausea, or apathy. 1
• Consider that nearly all drugs may affect appetite depending on dosage, body weight, renal function, and co-medication 1

Physical and Medical Factors

• Evaluate and treat:
  • Acute illness or chronic pain with adequate medical treatment 1
  • Chewing problems through dental evaluation or denture adjustment 1
  • Dysphagia requiring speech therapy consultation 1
  • Poor dentition necessitating dental referral 1
  • Oropharyngeal candidiasis 1
  • Constipation and nausea/vomiting 1

Psychosocial Assessment

• Screen for depression, as it commonly causes appetite loss and is treatable. 1
• Evaluate social support and isolation:
  • Lack of assistance with shopping and meal preparation 1
  • Family conflicts requiring resolution 1
  • Consider meals-on-wheels or shared meals 1

Nutritional and Functional Factors

• Document weight loss pattern: >3 kg (6.6 lbs) in 3 months is significant. 1
• Assess functional limitations affecting food intake (walking, meal preparation, money management) 1
• Remove dietary restrictions that may limit intake—these are potentially harmful in older adults. 1

Non-Pharmacological Interventions (Implement First)

Dietary Modifications

• Provide small, frequent meals with high-protein/high-calorie snacks. 1, 2
• Liberalize calorie-restricted diets 1
• Offer nutritional supplements when intake falls to 50-75% of usual 2
• Texture-modify foods if dysphagia is present 1

Environmental and Social Strategies

• Encourage shared meals with family or other patients to improve intake. 2
• Provide verbal prompting to remember to eat and drink 1
• Ensure adequate support with meal preparation 1

Referrals

• Nutritionist/dietician for comprehensive dietary planning 1, 2
• Physical therapy for gait, strength, and balance issues affecting function 1
• Occupational therapy for home safety and functional impairment 1
• Speech therapy if swallowing difficulties are present 1

Pharmacological Appetite Stimulation (Context-Specific)

For Patients WITH Concurrent Depression

Mirtazapine is the first-line pharmacological agent when depression coexists with appetite loss. 2

• Dosing: Start 7.5 mg at bedtime, maximum 30 mg at bedtime 2
• Duration: Full therapeutic trial requires 4-8 weeks 2
• Benefits: Addresses both depression and appetite; promotes sleep and weight gain 2
• Expected outcomes: Mean weight gain of 1.9 kg at 3 months and 2.1 kg at 6 months, with approximately 80% experiencing some weight gain 2
• Monitoring: Reassess at weeks 1,2,4,8, and 12; after 9 months consider dose reduction 2
• Discontinuation: Taper over 10-14 days to limit withdrawal symptoms 2

For Patients WITHOUT Depression (Months-to-Weeks Life Expectancy)

Consider appetite stimulants only if increased appetite is an important aspect of quality of life. 1

Megestrol Acetate (Second-Line)

• Dosing: 400-800 mg daily 1, 2
• Benefits: Approximately 1 in 4 patients will have increased appetite; 1 in 12 will gain weight 1, 2
• Critical safety concerns (FDA Warning): 3
  • 1 in 6 will develop thromboembolic phenomena 1
  • 1 in 23 will die 1
  • Risk of adrenal insufficiency and Cushing's syndrome 3
  • May cause edema, impotence, and vaginal spotting 2
  • Can attenuate benefits of resistance training 2
• Monitoring: Watch for signs of hypoadrenalism (hypotension, nausea, vomiting, dizziness, weakness) 3

Dexamethasone (Short-Term Use Only)

• Dosing: 2-8 mg/day for shorter life expectancy 2
• Advantage: Faster onset of action 2
• Caution: Significant side effects with prolonged use 2

Patients with Dementia WITHOUT Depression

Do not use appetite stimulants in dementia patients without concurrent depression—evidence shows no consistent benefit and potentially harmful side effects outweigh uncertain benefits. 2 (89% consensus agreement)

Medications NOT Recommended

Cannabinoids (dronabinol, cannabis) have insufficient evidence for appetite stimulation in older adults. 2

• Three small placebo-controlled trials in dementia patients found no significant effect on body weight, BMI, or energy intake 2
• Randomized trials in cancer patients showed no benefit over placebo 1

Critical Pitfalls to Avoid

• Do not initiate appetite stimulants before addressing reversible causes—medication review and treatment of depression, pain, and dental problems often resolve appetite issues without pharmacotherapy 1
• Do not use appetite stimulants in dementia without depression—risks outweigh benefits 2
• Do not overlook medication-induced appetite loss—it develops gradually and patients are often unaware 1
• Do not ignore the risk-benefit ratio of megestrol acetate—thromboembolic events and mortality risk are significant 1, 3
• Do not forget to monitor for adrenal insufficiency with chronic megestrol acetate use, especially during stress or intercurrent illness 3
• Do not use highly emetogenic chemotherapy regimens without aggressive antiemetic therapy in patients with poor appetite 1

Special Considerations for End-of-Life Care

If the patient is approaching end of life, focus on comfort and quality of life rather than aggressive nutritional goals. 2

• Overly aggressive nutritional interventions can increase suffering 2
• Consider appetite stimulants only if they align with patient goals and quality of life 1, 2