1 health economics comparing different allocations should we spent our money on wheel chairs...
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1
Health Economics
Comparing different allocations Should we spent our money on
• Wheel chairs
• Screening for cancer
Comparing costs
Comparing outcome
Outcomes must be comparable Make a generic outcome measure
2
Outcomes in health economics
Specific outcome are incompatible Allow only for comparisons within the specific field
• Clinical successes: successful operation, total cure
• Clinical failures: “events”
Generic outcome are compatible Allow for comparisons between fields
• Life years
• Quality of life
Most generic outcome Quality adjusted life year (QALY)
3
Quality Adjusted Life Years (QALY)
Multiply life years with quality index Quality of life index
1.0 = normal health
0.0 = death (extremely bad health)
Example Losing sense of sight
Quality of life index is 0.5
Life = 80 years
0.5 x 80 = 40 QALYs
4
A new wheelchair for elderly (iBOT) Special post natal care
Which health care program is the most cost-effective?
5
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 $ / QALYGM-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
Breast cancer screening 5,147
Viagra 5,097
Treatment of congenital anorectal malformations 2,778
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1.0
0.0A B C
Uti
lity
of
Hea
lth
Egalitarian Concerns:Burden of disease
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CE-ratio by equity
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Burden as criteria
0
5
10
15
20
25
30
Accepted Rejected
High burden Low burden
Pronk & Bonsel, Eur J Health Econom 2004, 5: 274-277
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Choice
First strongly preferred to second
First slightly
preferred to second
Unable to
choose
Second slightly
preferred to first
Second strongly preferred
to first
5 year old 70 year old 57 23 14 5 2
35 year old 60 year old 29 42 27 1 0
2 year old 8 year old 4 5 70 16 5
Single Married 3 3 69 20 5
Smoker Non-Smoker 6 8 43 30 12 Heavy drinker
Light drinker 5 6 25 41 23
Woman Man 4 4 90 1 0
Unemployed Employed 3 3 81 10 2
Director Unskilled 5 8 83 3 0
Lorry driver Teacher 2 2 86 8 3
With children No children 27 38 31 3 1
What form of equity?
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3500 Citations in PubMed
1980[pdat] AND (QALY or QALYs)
050
100150200250300350400450500
1980 1985 1990 1995 2000 2005 2010
Pu
bli
cati
on
s
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Top 6 journals Cost Utility Analysis
0 10 20 30 40 50
Pharmacoeconomics
Ann Intern Med
JAMA
Int J Technol Assess
Med Decis Making
Am J Med
# publications 1976 - 2003
www.tufts-nemc.org/cearegistry
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Most debate about the QoL estimates
Unidimensional QoL In QALY we need a unidimensional assessment of Quality of life
Rules out multidimensional questionnaires SF-36, NHP, WHOQOL
0
10
20
30
40
50
60
70
80
90
100
Physic
al fu
nctio
ning
Social
Functio
ning
Role P
hysi
cal
Role e
motio
nal
Men
tal h
ealth
Vitalit
y
Bodily p
ain
Genera
l Hea
lth
Sc
ore
s o
n S
F-3
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General pop.
Diabetes II
Growth hormon def.
Depression
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Utility assessment
Unidimensional QoL Often called ‘utility’
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Who to ask?
The patient, of course!
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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. “
• (Niel Aaronson, in B. Spilker: Quality of life and Pharmacoeconomics in Clinical Trails, 1996, page 180)
…therefore ask the patient!
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Patient values count….
[…] the best way to do this, the technology, is a patient-based assessment. They report, they evaluate, they tell you in a highly standardized way, and that information is used with the clinical data and the economic data to get the best value for the health care dollar.”
John Ware
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A problem in the patient perspective….
Stensman Scan J Rehab Med
1985;17:87-99.
Scores on a visual analogue scale 36 subjects in a
wheelchair
36 normal matched controls
Mean score Wheelchair: 8.0
Health 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 Consumer The patient does not pay
Consumer = General public Potential patients are paying
Health care is an insurance market A 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 servant Knowledge: professional
But suspected for strategical answers
• more money, less problems
• identify with unemployed persons
The unemployed persons themselves Knowledge: specific
But suspected for strategical answers
General public (politicians) Knowledge: experience
Payers
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Who’s values (of quality of life) should count in the health insurance?
Doctors Knowledge: professional
But suspected for strategical answers
• See only selection of patient
• Identification with own patient
Patients Knowledge: disease specific
But suspected for strategical answers
But coping
General public Knowledge: experience
Payers
Like costs: the societal perspective
24
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
Describe health states Have values from the general public
Rosser Matrix
QWB
15D
HUI Mark 2
HUI Mark 3
EuroQol EQ-5D
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EQ-5D, HUI and SF-36
Of the shelf instruments….
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Validated questionnaires
Rosser
EuroQol EQ-5D www.euroqol.org
QWB
SF-36 (SF-6D) www.sf-36.org
HUI Mark 2
HUI Mark 3
15D www.15d-instrument.net
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The Rosser & Kind Index
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The Rosser & Kind index
One of the oldest valuation 1978: Magnitude estimation
Magnitude estimation PTO
N = 70: Doctors, nurses, patients and general public
1982: Transformation to “utilities” 1985: High impact article
Williams A. For Debate... Economics of Coronary Artery Bypass Grafting. British Medical Journal 291: 326-28, 1985.
Survey at the celebration of 25 years of health economics: chosen most influential article on health economics
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More health states
Criticism on the Rosser & Kind index Sensitivity (only 30 health states)
The unclear meaning of “distress”
The compression of states in the high values
The involvement of medical personnel
New initiatives Higher sensitivity (more then 30 states)
More and better defined dimensions
Other valuation techniques
• Standard Gamble, Time Trade-Off
Values of the general public
31
Validated questionnaires
Questionnaire Number of health state
Rosser 30
EuroQol EQ-5D 245
QWB 2,200
SF-36 (SF-6D) 9,000
HUI Mark 2 24,000
HUI Mark 3 972,000
15D 3,052,000,000
32
No longer value all states
Impossible to value all health states If one uses more than 30 health states
Estimated the value of the other health states with statistical techniques Statistically inferred strategies
• Regression techniques
• EuroQol, Quality of Well-Being Scale (QWB)
Explicitly decomposed methods
• Multi Attribute Utility Theory (MAUT)
• Health Utility Index (HUI)
33
Statistically inferred strategies
Value a sample of states empirically Extrapolation
Statistical methods, like linear regression
11111 = 1.00
11113 = .70
11112 = ?
34
Explicitly Decomposed Methods
Value dimensions separately Between the dimensions What is the relative value of:
• Mobility…... 20%• Mood…….. 15%• Self care.… 24%.
Value the levels Within the dimensions What is the relative value of
• Some problems with walking…… 80%• Much problems with walking…... 50%• Unable to walk…………………….10%
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Explicitly Decomposed Methods
Combine values of dimensions and levels with specific assumptions Multi Attribute Utility Theory (MAUT)
• Mutual utility independence
• Structural independence
36
Explicitly Decomposed Methods
Health Utilities Index (Mark 2 & 3) Torrance at McMaster
8 dimensions
Mark 2: 24.000 health states
Mark 3: 972.000 health states
The 15-D Sintonen H.
15 dimensions
3,052,000,000 health states (3 billion)
37
More health states, higher sensitivity ? (1)
EuroQol criticised for low sensitivity Low number of dimensions
• Development of EQ-5D plus cognitive dimension
Low number of levels (3)
• Gab between best and in-between level
38
More health states, higher sensitivity ? (2)
Little published evidence Sensitivity EQ-5D < SF-36
• Compared as profile, not as utility measure
Sensitivity EQ-5D HUI
Sensitivity the number of health states How well maps the classification system the illness?
How valid is the modelling?
How valid is the valuation?
39
More health states, more assumptions
General public values at the most 50 states The ratios empirical (50) versus extrapolated
Rosser & Kind 1:1
EuroQol 1:5
QWB 1:44
SF-36 1:180
HUI (Mark III) 1:19,400
15D 1:610,000,000
What is the critical ratio for a valid validation?
40
SF-36 as utility instrument
Transformed into SF6D SG N = 610 Inconsistencies in model
18.000 health states
regression technique stressed to the edge
Floor effect in SF6D
41
Conflicting evidence sensitivity SF-36
Liver transplantation, Longworth et al., 2001
42
Conclusions
More states better sensitivity The three leading questionnaires
have different strong and weak points
43
Value a health state
Wheelchair Some problems in walking about
Some problems washing or dressing
Some problems with performing usual activities
Some pain or discomfort
No psychosocial problems
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Uni-dimensional value
Like the IQ-test measures intelligence Ratio or interval scale
Difference 0.00 and 0.80 must be 8 time higher than 0.10
Three popular methods have these pretensions Visual analog scale
Time trade-off
Standard gamble
45
Visual Analogue Scale
VAS Also 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 versusworse imaginable health
Dead
Normal health
X
46
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
47
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 feet
V(Wheels) = 80% or .8
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Consistent picture of difference
0.0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1.0
EQ-5D health states
Uti
liti
es
SG
TTOVAS
103 students
49
Health economics prefer TTO/SG
Visual analogue scale Easy
No trade-off: no relation to QALY
• No interval proportions
Standard Gamble / Time trade-Off Less easy
Trade-off: clear relation to QALY
• Interval proportions
Little difference between SG and TTO
50
Little difference between Cost/Life Year and Cost/QALY
Richard Chapman et al, 2004, Health Economics
51
Difference in QALYs makes little difference in outcome
Richard Chapman et al, 2004 “In a sizable fraction of cost-utility analyses,
quality adjusting did not substantially alter the estimated cost-effectiveness of an intervention, suggesting that sensitivity analyses using ad hoc adjustments or 'off-the-shelf' utility weights may be sufficient for many analyses.”
“The collection of preference weight data should […] should only be under-taken if the value of this information is likely to be greater than the cost of obtaining it.”
52
QALYs make a difference when:
Chronic disease Palliative Long term negative consequences
53
Conclusions
SG/TTO are preferred in Health economics Reproducible results
Problems in QALYs are overestimated Difference in QALYs makes little difference in outcome
• Compared to cost per life year
• With exception of chronic illness
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