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Cost-Effectiveness in Medicine
An Interactive Introduction
Jan J. v. Busschbach, Ph.D.Erasmus MC
• Institute for Medical Psychology and PsychotherapyViersprong Institute for studies on Personality Disorders
Presentations can be found at:www.busschbach.nl
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New cancer therapy
Symptoms Drug X Drug Y
Survival days 300 400
Days sick of chemotherapy 10 150
Days sick of disease 100 30
TWiST 190 220
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Time Without Symptoms of disease and subjective Toxic effects of treatment
TWiSTDeveloped by Richard Gelber (statistician)
In search for a typical “cancer” problemOften prolonged life but also a reductions in quality of
life
• At the beginning (side effects)
• At the endOnly count the days without symptoms of disease and
subjective toxic effects of the treatment
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TWiST in cancer therapy
0
20
40
60
80
100
120
140
160
180
1st Qtr 2nd Qtr 3rd Qtr 4th Qtr
First Year of treatment
Av
era
ge
nu
mb
er
of
TW
iST
's
Drug
Placebo
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Fit new therapy in fixed budget
50 patients each year (per hospital) Drug x: 50 x euro 1.750 = euro 87.500 Drug y: 50 x euro 2.000 = euro 100.000
Drug budget for x or y = euro 50.000 Number of patient
• Drug x: euro 50.000 / 1.750 = 28.5 patients
• Drug y: euro 50.000 / 2.000 = 25.0 patients Survival in days
• Drug x: 28.5 patients x 300 days = 8.550 days
• Drug y: 25.0 patients x 400 days = 10.000 days Survival in TWiST
• Drug x: 28.5 patients x 190 TWiST = 5.415 days
• Drug y: 25.0 patients x 220 TWiST = 5.500 days
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TWiST: ignores differences in quality of life
TWiSTHealthy = 1Sick (dead) = 0
There is more to life than sick/healthMake intermediate valuesQ-TWiST
• Quality of life adjusted adjusted TWiST
How to scale quality of life?0.0
Quality
of life
1.0
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Quality of life
“…. Health is physical, mental and social well-being and not merely the absence of disease or infirmity...”
World Health Organization, 1947
Extending health to well-being: Quality of life What is the definition of quality of life?
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Definitions of Quality of Life Quality of life is the degree of need and satisfaction within the physical,
psychological, social, activity, material and structural area (Hörnquist, 1982). Quality of life is the subjective evaluation of good and satisfactory character of
life as a whole (De Haes, 1988). Health related quality of life is the subjective experiences or preferences
expressed by an individual, or members of a particular group of persons, in relation to specified aspects of health status that are meaningful, in definable ways, for that individual or group (Till, 1992).
Quality of life is a state of well-being which is a composite of two components: 1) the ability to perform everyday activities which reflects physical psychological, and social well-being and 2) patient satisfaction with levels of functioning and the control of disease and/or treatment related symptoms (Gotay et al., 1992).
An individual’s perception of their position in life in the context of the culture and values systems in which they live and in relation to their goals, expectations, standards and concerns (WHO Quality of life Groups, 1993).
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No clear definition because:…
Many possible definitionsResearchers are free to choose The notion of measuring the quality of life could include the
measurement of practically anything of interest to anybody. And, no doubt, everybody could find arguments supporting the selection of whichever set of indicators to be his choice
• (Andrews & Withy, 1976, page 6)
Different origins of researchClinical decision making:…
• does the patient benefit from the treatment?Epidemiology (public health):…
• what is the morbidity of the population?Health economics:…
• is it worth the money?
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Common items in definitions:
It is not the doctor who reports Quality of life is subjective….
“Given its inherently subjective nature, consensus was quickly reached that quality of life ratings should, whenever possible, be elicited directly from patients themselves. “ (Aaronson, in B Spilker (Ed): Quality of life and Pharmacoeconomics in Clinical Trails, 1996, page 180)
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Common items in definitions:
Health related Multidimensional
Physical, psychological, social
QuestionnairesStandardize questions and response
• Reproducible results: sciences
• Quantify subjectivity
Operational definedLike IQ and temperature.
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How to measure quality of life form a clinical point of view?
Choose itemsAre you able to walk one kilometer ?Do you feel depressed ?
Choose response modeBinary yes / noMultiple (Likert) yes / at bid / hardly / noContinuous (Visual Analogue Scale) Always ————X—— Never
Combine items to dimensions of quality of lifeSum up the items belonging to one dimensionRescale sum on a scale from 0 to 100
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Multidimensionality in outcomes in health care
What if outcome conflict…e.g: better mobility, but worse roll emotionalOn has to weight or combine outcomes
What if some patients dies?Cancer therapy
• Better quality of life, but higher mortality Weight quality of life with mortality
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Value a health state
WheelchairSome problems in walking aboutSome problems washing or dressingSome problems with performing usual activitiesSome pain or discomfortNo psychosocial problems
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Visual Analogue Scale
VASAlso called “category scaling”From psychological research
“How is your quality of life?” “X” marks the spot
Rescale to [0..1]
Different anchor point possible:Normal health (1.0) versus dead (0.0)Best imaginable health versus
worse imaginable health
Dead
Normal health
X
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EuroQol EQ-5D
MOBILITY I have no problems in walking about I have some problems in walking about I am confined to bed
SELF-CARE I have no problems with self-care I have some problems washing or dressing myself I am unable to wash or dress myself
USUAL ACTIVITIES (e.g. work, study, housework family or leisure activities)
I have no problems with performing my usual activities I have some problems with performing my usual activities I am unable to perform my usual activities
PAIN/DISCOMFORT I have no pain or discomfort I have moderate pain or discomfort I have extreme pain or discomfort
ANXIETY/DEPRESSION I am not anxious or depressed I am moderately anxious or depressed I am extremely anxious or depressed
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Ratio scale in QoL
If we want to weight dimensions of QoL…. Values should be (at least) on interval scale Is it possible?
My Qol is today twice as good as yesterday Her IQ is twice as high…This painting is twice as beautiful as…His depression is twice as… My lecture is twice as….
Is a VAS ratio or interval?
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Uni-dimensional value
Ratio or interval scaleDifference 0.00 and 0.80 must be 8 time higher than 0.10
Two methods have these pretensionsTime trade-offStandard gamble
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Time Trade-Off
TTO Wheelchair
With a life expectancy: 50 years
How many years would you trade-off for a cure? Max. trade-off is 10 years
QALY(wheel) = QALY(healthy)Y * V(wheel) = Y * V(healthy)50 V(wheel) = 40 * 1
V(wheel) = .8
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Standard Gamble
SG Wheelchair Life expectancy is not important here How much are risk on death are you prepared to
take for a cure? Max. risk is 20% wheels = (100%-20%) life on feetV(Wheels) = 80% or .8
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TWiST: ignores differences in quality of life
TWiSTHealthy = 1Sick (dead) = 0
There is more to life than sick/healthMake intermediate valuesQ-TWiST
• Quality of life adjusted adjusted TWiST
How to scale quality of life?0.0
Quality
of life
1.0
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In health economics: Q-TWiST = QALY
Count life years Value (V) quality of life (Q)
V(Q) = [0..1] • 1 = Healthy• 0 = Dead
One dimension
Adjusted life years (Y) for value quality of life QALY = Y * V(Q)
• Y: numbers of life years• Q: health state• V(Q): the value of health state Q
Also called “utility analysis”
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A new wheelchair for elderly (iBOT) Special post natal care
Which health care program is the most cost-effective?
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A new wheelchair for elderly (iBOT) Increases quality of life = 0.1 10 years benefit Extra costs: $ 3,000 per life year QALY = Y x V(Q) = 10 x 0.1 = 1 QALY Costs are 10 x $3,000 = $30,000 Cost/QALY = 30,000/QALY
Special post natal care Quality of life = 0.8 35 year Costs are $250,000 QALY = 35 x 0.8 = 28 QALY Cost/QALY = 8,929/QALY
Which health care program is the most cost-effective?
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QALY league table
Intervention $ / QALY
GM-CSF in elderly with leukemia 235,958
EPO in dialysis patients 139,623
Lung transplantation 100,957
End stage renal disease management 53,513
Heart transplantation 46,775
Didronel in osteoporosis 32,047
PTA with Stent 17,889
STIP: Short-term inpatient psychotherapy 7,677
Breast cancer screening 5,147
Viagra 5,097
Treatment of congenital anorectal malformations 2,778
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Implications shifting threshold
QALY are weighted Weighted QALYs are maximized
Health is no longer the only thing maximized
Health status population will drop Differences in health will drop
Egalitarian consideration are incorporated
Burden of disease becomes a criteriaEquity
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The YAVIS patient in psychology
YAVISYoung, Attractive, Verbal, Intelligent and Successful
• Young, Attractive, Verbal, Intelligent, and Successful
• Young, Attractive, Verbal, Insightful, and Successful
• Young, Attractive, Vital, Intelligent, and Successful
• Young, Affluent, Verbal, Insured, and Single
Is there a ‘need’ for treatment? Is the QoL low?
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Personality disorder is not YAVIS
00.10.20.30.40.50.60.70.80.9
EQ-5D scores
Personality disorder
Intermittent claudication
Parkinson's disease
Low back pain
Type II diabetes
Schizophrenia outpatients
Hypertension
Asthma
Normal population
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The clinical perspective
Quality of life is subjective…..“Given its inherently subjective nature, consensus was quickly
reached that quality of life ratings should, whenever possible, be elicited directly from patients themselves. “ (Aaronson, in B Spilker (Ed): Quality of life and Pharmacoeconomics in Clinical Trails, 1996, page 180)
The patient values count in clinical quality of life research
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Coping (response shift)
StensmanScan J Rehab Med
1985;17:87-99.
Scores on a visual analogue scale
36 subjects in a wheelchair36 normal matched controls
Mean scoreWheelchair: 8.0Health controls: 8.3
Healthy
Death
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The economic perspective
In a normal market: the consumer values count The patient seems to be the consumer
Thus the values of the patients….
If indeed health care is a normal market… But is it….?
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Health care is not a normal market
Supply induced demands Government control
Financial support (egalitarian structure)
Patient ConsumerThe patient does not pay
Consumer = General publicPotential patients are paying
Health care is an insurance marketA compulsory insurance market
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Health care is an insurance market
Values of benefit in health care have to be judged from a insurance perspective
Who values should be used the insurance perspective?
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Who determines the payments of unemployment insurance?
Civil servantKnowledge: professionalBut suspected for strategical answers
• more money, less problems
• identify with unemployed persons
The unemployed persons themselvesKnowledge: specificBut suspected for strategical answers
General public (politicians)Knowledge: experiencePayers
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Who’s values (of quality of life) should count in the health insurance?
DoctorsKnowledge: professionalBut suspected for strategical answers
• See only selection of patient• Identification with own patient
PatientsKnowledge: disease specificBut suspected for strategical answersBut coping
General publicKnowledge: experiencePayersLike costs: the societal perspective
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The general public should be informed…
Valuing without knowledge makes no senseThyroid Eye Disease
Give description of the disease
A patient with bilateral thyroid eye disease with upper lid retraction and exophthalmos.
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…or use validated questionnaires
MOBILITY I have no problems in walking about I have some problems in walking about I am confined to bed
SELF-CARE I have no problems with self-care I have some problems washing or dressing myself I am unable to wash or dress myself
USUAL ACTIVITIES (e.g. work, study, housework family or leisure activities)
I have no problems with performing my usual activities I have some problems with performing my usual activities I am unable to perform my usual activities
PAIN/DISCOMFORT I have no pain or discomfort I have moderate pain or discomfort I have extreme pain or discomfort
ANXIETY/DEPRESSION I am not anxious or depressed I am moderately anxious or depressed I am extremely anxious or depressed
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Validated Questionnaires in the societal perspective
Describe health states Have values from the general public
Rosser MatrixQWB15DHUI Mark 2HUI Mark 3EuroQol EQ-5D