CLARIFYING CONFUSION: A RESEARCH APPROACH TO DELIRIUM

1. CLARIFYING CONFUSION:A RESEARCH APPROACHTO DELIRIUM Sharon K. Inouye, M.D., M.P.H. Professor of Medicine Yale University School of Medicine F:/shared/inouye/talks&slides/McMaster_Medical Grand Rounds.doc

2. WHAT IS DELIRIUM?(Acute Confusional State) Definition: • acute decline in attention and cognition Characteristics: • common problem • serious complications • often unrecognized • may be preventable

3. 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: >$8 billion

4. CURRENT IMPACT OF DELIRIUM • 35% of the U.S. population aged ≥ 65 years is hospitalized each year, accounting for > 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 > 2.2 million persons/year, involving > 17.5 million in-patient days/year • Estimated costs: > $8 billion/year

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

6. 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

7. DEVELOPMENT OF A DELIRIUM INSTRUMENT Ref: Inouye SK, et al. Ann Intern Med. 1990, 113: 941-8.

8. 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

9. KEY FEATURES OF DELIRIUM • Acute onset and fluctuating course • Inattention • Disorganized thinking • Altered level of consciousness Note: disorientation and inappropriate behavior not useful diagnostically

10. CAM ACUTE ONSET “Is there evidence of an acute change in mental status from the patient’s baseline?”

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

12. CAM INATTENTION “Did the patient have difficulty focusing attention, for example, being easily distractible, or having difficulty keeping track of what was being said?”

13. CAM DISORGANIZED SPEECH “Was the patient’s speech disorganized or incoherent, such as, rambling or irrelevant conversation, unclear or illogical flow of ideas, or unpredictable switching from subject to subject?”

14. CAM ALTERED LEVEL OF CONSCIOUSNESS “Overall how would you rate this patient’s level of consciousness?” Alert (normal) Vigilant (hyperalert) Lethargic (drowsy, easily aroused) Stupor (difficult to arouse) Coma (unarousable)

15. 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)

16. VALIDATION OF CAM Site ISite II (n=30) (n=26) 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)

17. 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

18. MULTIFACTORIAL MODEL OF DISEASE IN OLDER PERSONS

19. BASELINE VULNERABILITY Development and Validation of a Predictive Model for Delirium based on Admission Characteristics Ref: Inouye SK, et al. Ann Intern Med 1993;119:474-81.

20. 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.

21. 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

22. 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

23. INDEPENDENT RISK FACTORS FOR DELIRIUM(N=107)

24. PERFORMANCE OF THE PREDICTIVE MODELDevelopment of Delirium

25. PRECIPITATING FACTORS Development and Validation of a Predictive Model for Delirium based on Hospitalization – Related Factors Ref: Inouye SK, et al. JAMA 1996;275:852-7.

26. 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

27. 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 < 48 hours • Daily patient and nurse interviews

28. DEVELOPMENT OF THE PREDICTIVE MODEL • 11 variables entered into stepwise multivariable model • 5 independent factors selected for final model

32. IDENTIFICATION OF RISK FACTORS:SIGNIFICANCE • Helped determine which risk factors to address • Identified patients at high risk for delirium—to target for future preventive efforts • Provided groundwork needed for clinical programs and intervention trials

33. MULTIFACTORIAL ETIOLOGY OF COMMON GERIATRICS SYNDROMES • Falls • Dizziness • Incontinence • Pressure ulcers • Malnutrition • Functional decline

34. THE YALE DELIRIUM PREVENTION TRIAL Inouye SK. N Engl J Med. 1999;340:669-76.

35. RISK FACTORS FOR DELIRIUM • Cognitive Impairment • Sleep Deprivation • Immobilization • Vision impairment • Hearing Impairment • Dehydration

36. 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 FactorIntervention Cognitive Impairment……………………………….. Reality orientation Therapeutic activities protocol Sleep Deprivation……………………………………..Nonpharmacological 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

37. RATIONALE FOR MULTICOMPONENT APPROACH • Multifactorial etiology • Targeted risk factor approach • Most effective approach • Most clinically relevant approach

38. 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

40. YALE DELIRIUM PREVENTION TRIAL RESULTS

41. DELIRIUM PREVENTION TRIAL:SIGNIFICANCE • 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

42. 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. 1999;106:565-73

43. 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

44. 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

45. 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.