Description

• Capacity:
  • Involves a clinical evaluation by an authorized health care provider
  • Focuses on perceived ability of patient to participate with understanding in the process of informed consent
• Competence:
  • A legal determination of abilities, performed by a court judge
  • Involves medical information but not limited to medical issues
• Capacity is the currently preferred term to competence: legal capacity and medical capacity.
• A capacity determination is needed when arriving at a health care decision for testing, treatment or an intervention involving risk of harm or no improvement.
  • Any treating health care provider can evaluate capacity, including the provider also obtaining informed consent (although a psychiatrist or neuropsychiatric consultant is often asked to weigh in, other health care providers can determine capacity).
• Medical capacity is determined by:
  • Clinical observation and response to questions
  • Capacity assessment tool(s)
  • Cognitive assessment tool(s)
  • Interviews with a guardian or designated health care power of attorney (if indicated)
• The four “C”s of capacity are:
  • Context: comprehension of their health status
  • Choices: able to describe options
  • Consequences: able to explain possible outcomes
  • Consistency: continuity of choice selection
• Adequate cognition is a fundamental component but not the sole determinant of capacity (1).

Epidemiology

Most U.S. adults do not have an advanced directive—population studies show approximately 1/3 have completed an advanced directive (2).

Incidence
Need for capacity determination has been increased due to:

• Increasing patient longevity
• Prolonged chronic disease states
• Better patient rehabilitation opportunities
• Safer anesthetics and advanced postsurgery care

Prevalence
Prevalence varies based on the patient risk factors (pretest probability) and physician experience:

• ~3% of healthy outpatient seniors lack capacity (3).
• Highest rate of incapacity (68%) is in learning disabled patients.

Etiology and Pathophysiology

• Dementia is the most likely cause for individuals to be found incapable of making health care decisions in the outpatient setting.
• Capacity is a dynamic state; reassessment is necessary with each significant health care decision and informed consent.

Risk Factors

• For incapacity:
  • Longevity, multiple comorbidities, hospitalized for medical reasons
  • Never married, never worked outside home
• Insufficient informed consent:
  • Patient factors:
    • Health illiteracy
    • Excessive information
  • Provider factors:
    • Inexperience with process (e.g., house staff)
    • Insufficient discussion time

General Prevention

Early assessment and periodic reassessment of capacity in:

• Dynamic patient conditions, like electrolyte imbalance, closed head injuries, delirium states
• After procedures with anesthesia or analgesics
• Enhancement and dissipation of mind altering substances

Commonly Associated Conditions

• Dementia/Alzheimer disease, Parkinson disease, and traumatic brain injury
• Schizophrenia, depression, and substance abuse
• Acute illness, metabolic derangement