What are the criteria for diagnosing adult failure to thrive (FTT)?

Criteria for Adult Failure to Thrive

Adult failure to thrive (FTT) is diagnosed when an older adult exhibits a multifactorial decline characterized by weight loss, decreased appetite, poor nutrition, and decreased physical functioning, often accompanied by social withdrawal and cognitive changes.

Diagnostic Criteria

The diagnosis of adult failure to thrive requires evidence of decline in multiple domains:

Physical Parameters

• Weight below the 10th percentile for age or crossing two major percentile lines downward 1
• Unintentional weight loss
• Malnutrition (underweight status with BMI <18.5 kg/m²) 2
• Decreased physical functioning and activity levels 3, 4

Functional Domains

Four key syndromes that must be assessed and are predictive of adverse outcomes:

1. Impaired Physical Function

   • Decline in activities of daily living (ADLs)
   • Decreased mobility
   • Reduced strength and endurance
   • Increased dependency on others

2. Malnutrition

   • Poor appetite
   • Inadequate food intake
   • Weight loss
   • Low albumin or other nutritional markers

3. Depression

   • Social withdrawal
   • Loss of interest in activities
   • Depressed mood
   • Poor motivation

4. Cognitive Impairment

   • Memory loss
   • Confusion
   • Decreased executive function
   • Impaired decision-making

Assessment Approach

Initial Evaluation

• Comprehensive functional assessment of ADLs and instrumental ADLs
• Nutritional assessment including weight history, appetite changes, and dietary intake
• Depression screening using validated tools
• Cognitive assessment
• Medication review to identify potential contributors
• Social and environmental assessment

Laboratory and Diagnostic Testing

• Complete blood count
• Comprehensive metabolic panel
• Thyroid-stimulating hormone
• Urinalysis
• Additional targeted testing based on clinical presentation

Differential Diagnosis

Adult failure to thrive must be distinguished from:

• Single-system disease processes
• Normal aging
• End-stage disease
• Specific geriatric syndromes in isolation

Management Considerations

The management of adult failure to thrive should target the identified contributing factors:

• Nutritional Interventions

  • High-calorie, nutrient-dense foods
  • Nutritional supplements
  • Addressing barriers to eating

• Physical Function

  • Physical therapy
  • Exercise programs
  • Assistive devices

• Psychological Support

  • Treatment of depression
  • Cognitive behavioral therapy
  • Social engagement opportunities

• Medical Management

  • Treatment of underlying medical conditions
  • Medication adjustment
  • Management of chronic diseases

Important Considerations

• Adult failure to thrive should be recognized as a key decision point in care, prompting discussion of goals of care and end-of-life options 4
• The diagnosis requires a deconstructionist approach to identify and address specific contributing factors rather than accepting decline as inevitable 3
• Depression is often a significant contributor but may be overlooked; early diagnosis and treatment of depression can prevent progression to failure to thrive 5
• The term originated from pediatrics but has been adapted to describe a distinct geriatric syndrome 6

Clinical Pitfalls to Avoid

• Fatalism: Assuming decline is inevitable and not pursuing potentially reversible causes
• Intellectual laziness: Not thoroughly investigating all contributing factors
• Overlooking depression: Depression is a common and treatable cause of failure to thrive symptoms
• Medication effects: Not reviewing medications that may contribute to symptoms
• Focusing on a single domain: Failing to assess all four key domains (physical function, nutrition, depression, cognition)

Adult failure to thrive represents a complex interplay of physical, psychological, social, and environmental factors requiring a comprehensive assessment and targeted interventions to prevent further functional decline and improve quality of life.