CLARIFYING CONFUSION: A RESEARCH APPROACH TO DELIRIUM

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CLARIFYING CONFUSIONA RESEARCH APPROACHTO
DELIRIUM

• Sharon K. Inouye, M.D., M.P.H.
• Professor of Medicine
• Yale University School of Medicine
• F/shared/inouye/talksslides/McMaster_Medical
  Grand Rounds.doc

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WHAT IS DELIRIUM?(Acute Confusional State)

• Definition
• acute decline in attention and cognition
• Characteristics
• common problem
• serious complications
• often unrecognized
• may be preventable

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EPIDEMIOLOGY OF DELIRIUM

• Prevalence (on admission) 10-40
• Incidence (in hospital) 25-60
• Hospital mortality 10-65
• 2-20 x controls
• Excess annual health
• care expenditures gt8 billion

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CURRENT IMPACT OF DELIRIUM

• 35 of the U.S. population aged 65 years is
  hospitalized each year, accounting for gt 40 of
  all inpatient days
• Assuming a delirium rate of 20
• 7 of all persons 65 years will develop
• delirium annually
• Delirium will complicate hospital stay for gt 2.2
  million persons/year, involving gt 17.5 million
• in-patient days/year
• Estimated costs gt 8 billion/year

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IMPACT OF DELIRIUM

• Beyond hospital costs
• Post-hospital costs
• Institutionalization
• Rehabilitation
• Home care
• Caregiver burden
• Aging of U.S. population

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RECOGNITION OF DELIRIUM

• Previous studies 32-66 cases unrecognized by
  physicians
• Yale-New Haven Hospital study (1988-1989)
• 65 (15/23) unrecognized by physicians
• 43 (10/23) unrecognized by nurses

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DEVELOPMENT OF A DELIRIUM INSTRUMENT

• Ref Inouye SK, et al. Ann Intern Med. 1990,
  113 941-8.

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CONFUSION ASSESSMENT METHOD(CAM)

• Developed to provide a quick, accurate method
  for detection of delirium
• For non-psychiatrically trained clinicians
• Both clinical and research settings

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KEY FEATURES OF DELIRIUM

• Acute onset and fluctuating course
• Inattention
• Disorganized thinking
• Altered level of consciousness
• Note disorientation and inappropriate
  behavior not useful diagnostically

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CAM

• ACUTE ONSET
• Is there evidence of an acute change in
• mental status from the patients baseline?

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CAM

• FLUCTUATING COURSE
• Did this behavior fluctuate during the past
• day, that is, tend to come and go or
• increase and decrease in severity?

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CAM

• INATTENTION
• Did the patient have difficulty focusing
  attention,
• for example, being easily distractible, or
  having
• difficulty keeping track of what was being said?

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CAM

• DISORGANIZED SPEECH
• Was the patients speech disorganized or
  incoherent, such
• as, rambling or irrelevant conversation,
  unclear or illogical
• flow of ideas, or unpredictable switching from
  subject to
• subject?

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CAM

• ALTERED LEVEL OF CONSCIOUSNESS
• Overall how would you rate this patients level
  of consciousness?
• Alert (normal)
• Vigilant (hyperalert)
• Lethargic (drowsy, easily aroused)
• Stupor (difficult to arouse)
• Coma (unarousable)

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SIMPLIFIED DIAGNOSTIC CRITERIA

• -- Uses 4 criteria assessed by CAM
• (1) acute onset and fluctuating course
• (2) inattention
• (3) disorganized thinking
• (4) altered level of consciousness
• -- The diagnosis of delirium requires the
  presence of criteria
• (1), (2) and (3) or (4)

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VALIDATION OF CAM

• Site I Site II
• (n30) (n26)
• Sensitivity 10/10 (100) 15/16 (94)
• Specificity 19/20 (95) 9/10 (90)
• Positive predictive
• accuracy 10/11 (91) 15/16 (94)
• Negative predictive
• accuracy 19/19 (100) 9/10 (90)
• Likelihood ratio 20.0 9.4
• (positive test)

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CAM SIGNIFICANCE

• Helped to improve recognition of delirium
• Widely used standard tool for clinical and
  research purposes nationally and internationally
• Translated into five languages
• Used in over 100 original published studies to
  date

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MULTIFACTORIAL MODEL OF DISEASE IN OLDER PERSONS
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BASELINE VULNERABILITY

• Development and Validation of a Predictive Model
  for Delirium based on Admission
  Characteristics
• Ref Inouye SK, et al. Ann Intern Med
  1993119474-81.

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SPECIFIC AIMS

• To identify risk factors for the development of
  delirium.
• To develop and validate a predictive model for
  development of delirium based on admission
  characteristics.

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METHODS

• Patients 2 prospective cohorts of consecutive
  patients age 70 years on the medicine service,
  done in tandem, with 107 and 174 patients
• Assessments Daily patient and nurse
  interviews, with CAM ratings

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DEVELOPMENT OF THE PREDICTIVE MODEL

• 13 variables with RR 1.5 entered into a
  stepwise multivariable model
• 4 risk factors selected for the final predictive
  model

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INDEPENDENT RISK FACTORS FOR DELIRIUM(N107)
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PERFORMANCE OF THE PREDICTIVE MODEL
Development of Delirium
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PRECIPITATING FACTORS

• Development and Validation of a Predictive
• Model for Delirium based on
• Hospitalization Related Factors
• Ref Inouye SK, et al. JAMA
  1996275852-7.

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SPECIFIC AIMS

• To identify potential precipitating factors for
  delirium
• To develop a predictive model for delirium based
  on precipitating factors, then to validate this
  model in an independent sample
• To study the inter-relationship of baseline and
  precipitating factors for delirium

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METHODS

• Two prospective cohort studies, in tandem
• Development Cohort 11/6/89 6/22/90
• Validation Cohort 7/9/90 7/31/91
• Eligibility Consecutive patients admitted to
  the medicine
• service at Yale-New Haven Hospital
• Exclusion Delirium on admission
• Inability to be interviewed (e.g. intubation,
  coma)
• Discharge in lt 48 hours
• Daily patient and nurse interviews

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DEVELOPMENT OF THE PREDICTIVE MODEL

• 11 variables entered into stepwise multivariable
  model
• 5 independent factors selected for final model

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IDENTIFICATION OF RISK FACTORSSIGNIFICANCE

• Helped determine which risk factors to address
• Identified patients at high risk for deliriumto
  target for future preventive efforts
• Provided groundwork needed for clinical programs
  and intervention trials

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MULTIFACTORIAL ETIOLOGY OF COMMON GERIATRICS
SYNDROMES

• Falls
• Dizziness
• Incontinence
• Pressure ulcers
• Malnutrition
• Functional decline

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THE YALE DELIRIUM PREVENTION TRIAL

• Inouye SK. N Engl J Med. 1999340669-76.

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RISK FACTORS FOR DELIRIUM

• Cognitive Impairment
• Sleep Deprivation
• Immobilization
• Vision impairment
• Hearing Impairment
• Dehydration

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YALE DELIRIUM PREVENTION PROGRAM

• Designed to counteract iatrogenic influences
  leading to delirium in the hospital
• Multicomponent intervention strategy targeted at
  6 delirium risk factors
• Risk Factor Intervention
• Cognitive Impairment.. Reality
  orientation
• Therapeutic activities protocol
• Sleep Deprivation..Nonpharmacologica
  l sleep protocol
• Sleep enhancement protocol
• Immobilization.. Early
  mobilization protocol
• Minimizing immobilizing equipment
• Vision Impairment. Vision aids
• Adaptive equipment
• Hearing Impairment. Amplifying
  devices
• Adaptive equipment and techniques
• Dehydration Early recognition
  and volume repletion

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RATIONALE FOR MULTICOMPONENT APPROACH

• Multifactorial etiology
• Targeted risk factor approach
• Most effective approach
• Most clinically relevant approach

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YALE DELIRIUM PREVENTION TRIAL METHODS

• Design controlled clinical trial with
  individual matching from
• 3/25/95 3/28/98
• Subjects patients 70 years old without
  evidence of delirium, but at moderate to high
  risk for developing delirium. Sample size
  852 (426 intervention, 426 controls)
• Units one intervention and 2 control (usual
  care) units
• Procedures baseline, daily, and 1 mo, 6 mo, 12
  mo follow-up interviews by trained clinical
  research staff, blinded to study hypotheses and
  interventional nature

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YALE DELIRIUM PREVENTION TRIAL RESULTS
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DELIRIUM PREVENTION TRIALSIGNIFICANCE

• Practical, real-world intervention strategy
  targeted towards evidence-based risk factors
• Significant reduction in risk of delirium and
  total delirium days, without significant effect
  on delirium severity or recurrence
• Primary prevention of delirium likely to be most
  effective treatment strategy
• Targeted, multicomponent strategy works

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DELIRIUMHEALTH POLICY IMPLICATIONS

• Delirium serves as a marker for quality of
  hospital care for the elderly
• Often iatrogenic
• Linked to processes of care
• Common, bad outcomes
• Delirium serves as a window for identifying
  quality improving changes.
• Inouye SK. Am J Med. 1999106565-73

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PATHWAYS LEADING TO DELIRIUM

• Iatrogenesis
• Failure to recognize delirium
• Attitudes towards care of the elderly
• Rapid pace and technologic focus
• of health care
• Reduction in skilled nursing staff

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RECOMMENDED INTERVENTIONS TO REDUCE DELIRIUM

• LOCAL
• Cognitive assessment of all older patients
• Monitoring mental status as a vital sign
• Strategies to change practice patterns leading to
  delirium
• Clinical guidelines/pathways for care of
  high-risk geriatric patients and delirium
• Enhanced geriatric nursing and physician
  expertise at bedside
• Case management to enhance coordination of care
• NATIONAL
• Provider education and continuing education
  requirements
• Improved quality monitoring systems delirium as
  sentinel event
• Create environments that facilitate high-quality
  geriatric care

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CONCLUSIONS

• Delirium is a common, serious problem for
  hospitalized older patients.
• Recognition may be improved by use of simplified
  diagnostic criteria.
• The etiology of delirium is multifactorial,
  involving vulnerability and precipitating
  factors.
• Many cases may be preventable through a targeted
  risk factor approach.
• Delirium serves as a quality marker for hospital
  care.