why use the eq-5d?
Post on 24-Feb-2016
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Why use the EQ-5D?
What are the alternatives?
What are the alternatives for Direct valuation?
• Other VAS• Time Trade-Off• Standard Gamble• Willingness to pay• Difficult…
– Paired comparisons
– DCE etc
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 versus
worse imaginable health Dead
Normal health
X
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
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 .80
Willingness to pay• Cost benefit analyis• Revealed preferences
– Look in market how much subject are willing to pay
– Different situations give different results
– Weighted by in income• Conclusion:
– the validity of cost benefit analysis is not sufficient
Alternatives for indirect measurements
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
Validated questionnaires Rosser & Kind EuroQol EQ-5D www.euroqol.org QWB SF-36 (SF-6D) www.sf-36.org HUI Mark 2 HUI Mark 3 www.healthutilities.com 15D www.15d-instrument.net
The Rosser & Kind Index
The Rosser & Kind index
• Criticism on the Rosser & Kind index– Sensitivity (only 30 health states)
• New initiatives– Higher sensitivity (more then 30 states)
• EuroQol Group– EQ-5D-3L and the EQ-5D-5L
• McMaster University– Health Utility Index 2 & 3
• SF-36– SF-6D
Health Utility Index
• Developed from pediatric care– Strong proxy versions
• Symptom driven: – “Outside the skin” instead of “inside the skin”
• EQ-5D: “problems with daily activity”• HUI: “Unable to read ordinary newsprint…”
• Commercial– All user have to pay
• 35 Translations
HUI 2
HUI 3
Increasing number of health states
Questionnaire Number of health state Rosser 30 EuroQol EQ-5D 243 QWB 2,200 SF-36 (SF-6D) 9,000 HUI Mark 2 24,000 HUI Mark 3 972,000 15D 3,052,000,000
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)
Statistically inferred strategies
• Value a sample of states empirically• Extrapolation
– Statistical methods, like linear regression– 11111 = 1.00– 11113 = .70– 11112 = ?
Statistically inferred strategies
• EuroQol– EQ-5D: 5 dimensions of health– 245 health states
• Quality of Well-Being scale (QWB)– 4 dimensions of health– 2200 health states plus 22 additional symptoms
• SF-36– SF-6D: 6 dimensions of health– 18.000 health states
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%
• 21111 = 1 - (0.20 x (1.00 - 0.80)) = 0.96
Explicitly Decomposed Methods
• Combine values of dimensions and levels with specific assumptions– Multi Attribute Utility Theory (MAUT)
• Mutual utility independence• Structural independence
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)
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
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?
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?
Conflicting evidence sensitivity SF-36
Liver transplantation, Longworth et al., 2001
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
Collapsing levels SF-6D
• Many levels are taken together– If PF=2 decrement: - 0.056– If PF=3 decrement: - 0.056
– If RL=2 decrement: - 0.073– If RL=3 decrement: - 0.073– If RL=4 decrement: - 0.073
SF-6D loses a lot of levels• Levels clas.system and actual levels
– PF 6 5– RL 4 2– SF 5 5– PN 6 5– MH 5 4– VI 5 3
• Levels in clas. system: 18.000– 6x4x5x6x5x5
• Actual levels: 480– 5x2x5x5x4x3
Some levels in the SF-6D do not work…
Dimension: Physical Functioning (PF) If PF=1 decrement: 0 If PF=2 decrement: - 0.056 If PF=3 decrement: - 0.056 If PF=4 * decrement: - 0.072 If PF=5 * decrement: - 0.080 If PF=6 * decrement: - 0.134 Dimension: Role Limitations (RL) If RL=1 decrement: 0 If RL=2 decrement: - 0.073 If RL=3 * decrement: - 0.073 If RL=4 * decrement: - 0.073
EQ-5D• Strong punts
– Very sensitive in the low– Measures subjective burden (inside the skin)– Low administrative burden– Many translations– Cheap– Most used QALY questionnaire– Most international validations
• Weak points– Only there levels per dimensions– Insensitive in the high regions
HUI
• Strong punts– Sensitive– Measures objective burden (outside the skin)– Well developed proxy versions– Well developed child versions
• Weak points– Expensive– Only a few valuation studies
SF-6D
• Strong punts– Probably sensitive in the high regions– Often already include in trials (SF-36)– Many translations
• Weak points– Insensitive in the low regions– Only a few validation study– Might be expensive
Conclusions
• More states better sensitivity• The three leading questionnaires
– have different strong and weak points
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