NIHES Disease specific 5
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Transcript NIHES Disease specific 5
The valuation of disease-specific
questionnaires for QALY analysis
To
rescue data in absence of an utility measure
To
increase sensitivity
Growth hormone deficiency in adults
Benign Prostatic Hyperplasia (BPH)
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Mapping
Trying
‘to map’ disease
characteristics on EQ-5D etc.
Nord E. Cost-utility analysis of
Melphalan plus Prednisone with or
without Interferon Alfa-2b in newly
diagnosed multiple myeloma.
Pharmacoeconomics 1997;12:89-103.
Can
be done behind the desk
Very quick…
Very dirty…
A
low face validity…
2
Mapping
DALY style
3
QoL-AGHDA
Quality
of Life Adult Growth Hormone
Deficiency Assessment
25 yes/no items
Internet
panel
N = 1075
Both
AGDHA and EQ-5D
4
From AGDHA to utilities (QALY)
EQ-5D: 5 dimensions
AGHDA: 25 dimensions
Utility
Algorithm
Utilities
Sum
Score
Regression
Total score
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Regression Dutch AGHDA sum score
on EQ-5D
1
EQ-5D NL
0.8
0.6
EQ-5D = 0.980 - 0.0198 x AGHDA
R2 = .344
0.4
0.2
0
0
5
10
15
20
25
AGHDA
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EQ-5D-3L versus EQ-5D-5l
Zet bij iedere groep in de lijst hieronder een kruisje in het hokje achter de zin die het
best past bij uw eigen gezondheidstoestand vandaag.
Zet bij iedere groep in de lijst hieronder een kruisje in het hokje achter de zin die het
best past bij uw eigen gezondheidstoestand vandaag.
Mobiliteit
Mobiliteit
Ik heb geen problemen met lopen
Ik heb een beetje problemen met lopen
Ik heb matige problemen met lopen
Ik heb ernstige problemen met lopen
Ik ben niet in staat niet om te lopen
Ik heb een beetje problemen met mijzelf wassen of aankleden
Ik heb matige problemen met mijzelf wassen of aankleden
Ik heb ernstige problemen met mijzelf wassen of aankleden
Ik ben niet in staat mijzelf te wassen of aan te kleden
Ik heb enige problemen met lopen
Ik ben bedlegerig
Ik heb enige problemen om mijzelf te wassen of aan te kleden
Ik ben niet in staat mijzelf te wassen of aan te kleden
gezins- en vrijetijdsactiviteiten)
Ik heb enige problemen met mijn dagelijkse activiteiten
gezins- en vrijetijdsactiviteiten)
Ik heb geen problemen met mijn dagelijkse activiteiten
Ik heb een beetje problemen met mijn dagelijkse activiteiten
Ik heb matige problemen met mijn dagelijkse activiteiten
Ik heb ernstige problemen met mijn dagelijkse activiteiten
Ik ben niet in staat mijn dagelijkse activiteiten uit te voeren
Dagelijkse activiteiten (bijv. werk, studie, huishouden,
Ik heb geen problemen met mijn dagelijkse activiteiten
Dagelijkse activiteiten (bijv. werk, studie, huishouden,
Zelfzorg
Ik heb geen problemen om mijzelf te wassen of aan te kleden
Zelfzorg
Ik heb geen problemen met mijzelf wassen of aankleden
Ik heb geen problemen met lopen
Ik ben niet in staat mijn dagelijkse activiteiten uit te voeren
Stemming
Pijn/klachten
Ik heb geen pijn of andere klachten
Ik heb matige pijn of andere klachten
Ik heb zeer ernstige pijn of andere klachten
Pijn/ongemak
Ik heb geen pijn of ongemak
Ik heb een beetje pijn of ongemak
Ik heb matige pijn of ongemak
Ik heb ernstige pijn of ongemak
Ik heb extreme pijn of ongemak
Angst/somberheid
Ik ben niet angstig of somber
Ik ben een beetje angstig of somber
Ik ben matig angstig of somber
Ik ben erg angstig of somber
Ik ben extreem angstig of somber
Ik ben niet angstig of somber
Ik ben matig angstig of somber
Ik ben erg angstig of somber
Cross walk
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Validation
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Calculation
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The AGHDA has generic features…
AGHDA
I have to struggle to finish jobs
I feel a strong need to sleep during the day
I often feel lonely even when I am with other people
EQ-5D
I have some problems with performing my usual activities
I am moderate anxious or depressed
makes sense
AGHDASUM
30
20
10
Percent
Correlation
0
.00
4.00
2.00
AGHDASUM
8.00
6.00
12.00
10.00
16.00
14.00
20.00
18.00
24.00
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22.00
But what if the measure has
little generic features?
International Symptom Prostate Score (IPSS)
BPH
Enlargement of the prostate
Causes voiding problems in elderly men
• Difficulties to pee
7 questions: How often have you
had to push or strain to begin urination?
had a sensation of not emptying your bladder completely?
had to urinate again less than two hours after you finished urinating?
found you stopped and started again several times when you
urinated?
you find it difficult to postpone urination?
had a weak urinary stream?
How many times did you most typically get up to urinate from the time
you went to bed at night until the time you got up in the morning?
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Does the EQ-5D make sense in BPH?
MOBILITY
SELF-CARE
I have no problems with self-care
I have some problems…..
I am unable…
USUAL ACTIVITIES
I have no problems in walking about
I have some…….
I am confined to bed
I have no problems with performing my usual
activities
I have some problems…
I am unable….
PAIN/DISCOMFORT
I have no pain or discomfort
I have moderate …..
I have extreme……..
ANXIETY/DEPRESSION
I am not anxious or depressed
I am moderately……..
I am extremely…..
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Can we convert the IPSS
outcomes into utilities?
Attribute
TTO values to the IPSS health states
Problem: IPSS has 279.936 health states
7 items, 6 answer levels = 6x6x6x6x6x6x6 = 279.936 health
states
Too many to value with TTO
Reduce
number of health states
Reduce items
• Factor analysis
Reduce answer levels
• Combine answer levels
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Reduce number of health states
Factor
analysis on patients IPSS responses
N = 1414
Two
main factors
Obstructive (alpha= 0.8018)
Irritative (alpha= 0.7165)
• Confirmed in literature
Factors
divided in 3 levels
Number of health states reduced to 33 = 9
Can be valued directly
TTO
General public, representative for gender/age (N=170)
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Exercise
Value
the 9 health states of the reduced IPSS
Tests feasibility: can it be done?
Compare
values with earlier research
Test reliability: can we repeat the observation?
• Scientific prove (observation is independent of
examination)
• Do different groups of people have different values
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QALY weights for BPH
utilities (TTO)
1
0,95
0,9
0,85
0,8
0,75
0,7
0,65
irritative
0,6
seldom/never
sometimes
almost always
0,55
0,5
ys
es
lwa
a
ver
tim
t
e
e
s
n
/
o
som
om
alm
seld
obstructive
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TTO
Comparing ISPOR 2003 with
population
1.0
0.9
0.8
0.7
0.6
0.5
0.4
0.3
0.2
0.1
0.0
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12
13
21
22
23
13
23
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Health states IPSS
ISPOR 2003
Population
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How to come to these values?
O b stru ctive score
S um (IP S S 1 + IP S S 2 + IP S S 4 + IP S S 6)
Irritative score
S um (IP S S 3 + IP S S 5 + IP S S 7)
A s exam p le: o b stru ctive 1 an d irritative 2 = u ti 1_2
A n s w e r le ve ls :
Q uality of life values:
D o m a in
s c o re
L e ve l
O b stru ctive
( <= 4)
O b stru ctive 1
( >= 5 & <= 16)
O b stru ctive 2
( >= 17)
Irrita tive
irrita tive
1 .0 0
.9 7
.9 5
1
O b stru ctive 3
.9 7
.9 4
.9 2
2
(< = 3 )
Irrita tive 1
.9 2
.9 0
.8 7
3
( >= 4 & <= 9)
Irrita tive 2
1
2
3
( >= 10)
Irrita tive 3
O b s tru c tive
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Treatment effect
0,98
0,97
0,96
utilities
0,95
0,94
0,93
0,92
0,91
surgery (n= 144)
alpha-blockers (n=33)
finasteride (n=35)
watchful waiting (n=159)
0,9
baseline
follow up
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Disease specific utilities are not on
a generic scale
Generic
top anchor
Specific
top anchor
Healthy
No disease specific
problems
Death
All disease specific
complains
absence of any impairment
absence of specific impairment
Co morbidity might still be present
Disease specific utilities are a
subscale of a generic scale
No disease specific
problems
Healthy
Rescaling
necessary
All disease specific
complains
Death
Raw disease specific trade-off
ten to overestimated gains
Value
of life years “traded off” in TTO
differently
Healthy subject:
1 life year is 1.0 QALY
Sick subject:
1 life year is 0.8 QALY
Life years of healthy persons are more worth than those of
sick
Disutility
is proportional
20% trade off at 1.00: disutility = 0.20
20% trade off at 0.80: disutility = 0.16
20% trade off at 0.60: disutility = 0.12
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Specific utilities should be
corrected for average morbidity
Solution: multiplicative model
Multiply disease specific value with average value
Values have to be multiplied by average value for age
group.
For instance in IPSS
• male age 55-64: overall QoL utility: 0.81
• Most severe BPH: 0.87
• Male age 55-64 with most severe BPH: 0.81 x 0.87 = .7047
Maximum gain reduces from
Raw score
Adjust score
15 % reduction
1.00 - 0.87 = 0.13
0.81 - 0.70 = 0.11
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Rue of thumb
Overestimated
CE-ration by 15% using
specific utilities
Proposed by Fryback & Lawrence, MDM 1997
• For not completely the same problem…
• …for own health states, not imaginable health states
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Conclusion
We
validated the IPSS for the use in economic
appraisal
Now, IPSS has QALY-weights
New and already published research can be converted into
QALYs
Advantage
use specific QALYs measures
High sensitive disease specific measures for QALY-analysis
Rescuing data
Disadvantages
Not directly compatible with generic utilities
± 15 % correction needed in disease specific
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