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 1

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) 2

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 3

Which health care program is the most cost-effective?



A new wheelchair for elderly (iBOT)



Special post natal care

4

Which health care program is the most cost-effective?

 

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 5

QALY league table Intervention

GM-CSF in elderly with leukemia EPO in dialysis patients Lung transplantation End stage renal disease management Heart transplantation Didronel in osteoporosis PTA with Stent Breast cancer screening Viagra Treatment of congenital anorectal malformations

$ / QALY

235,958 139,623 100,957 53,513 46,775 32,047 17,889 5,147 5,097 2,778 6

1.0

Egalitarian Concerns: Burden of disease 0.0

A B C

7

CE-ratio by equity

8

Burden as criteria 30 25 20 15 10 5 0 Accepted High burden Rejected Low burden Pronk & Bonsel, Eur J Health Econom 2004, 5: 274-277

9

What form of equity?

Choice

5 year old 35 year old 2 year old Single Smoker Heavy drinker Woman Unemployed Employed Director 70 year old

First strongly preferred to second

57 60 year old 8 year old Married Non-Smoker Light drinker Man Unskilled 29 4 3 6 5 4 3 5 Lorry driver Teacher With children No children 2 27

First slightly preferred to second

23 42 5 3 8

Unable to choose

14 27 70 69 43

Second slightly preferred to first

5 1 16 20 30 6 4 3 8 2 38 25 90 81 83 86 31 41 1 10 3 8 3

Second strongly preferred to first

2 0 5 5 12 23 0 2 0 3 1 10

3500 Citations in PubMed 1980[pdat] AND (QALY or QALYs)

500 450 400 350 300 250 200 150 100 50 0 1980 1985 1990 1995 2000 2005 2010 11

Top 6 journals Cost Utility Analysis Am J Med Med Decis Making Int J Technol Assess JAMA Ann Intern Med Pharmacoeconomics 0 www.tufts-nemc.org/cearegistry 10 20 30 # publications 1976 - 2003 40 50

12

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

100 90 80 70 60 50 40 30 20 10 0 P hy si ca l f un ct ion ing S oc ia l Fu nc tion in g R ol e P hy si ca R ol l e em ot io na l M ent al he al th V ita lit y B od ily pa in G ene ra l H ea lth General pop.

Diabetes II Growth hormon def.

Depression

13

Utility assessment



Unidimensional QoL



Often called ‘utility’

14

Who to ask?

The patient, of course!

15

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!

16

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

17

A problem in the patient perspective….

Healthy 

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

Death 18

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….?

19

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 20

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?

21

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 22

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 23

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 24

Validated Questionnaires



Describe health states



Have values from the general public

 Rosser Matrix      QWB 15D HUI Mark 2 HUI Mark 3 EuroQol EQ-5D 25

EQ-5D, HUI and SF-36 Of the shelf instruments….

26

Validated questionnaires Rosser EuroQol EQ-5D QWB SF-36 (SF-6D) HUI Mark 2 HUI Mark 3 15D www.euroqol.org www.sf-36.org www.15d-instrument.net

27

The Rosser & Kind Index

28

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 29

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 30

Validated questionnaires Questionnaire Rosser EuroQol EQ-5D Number of health state 30 245 QWB SF-36 (SF-6D) HUI Mark 2 HUI Mark 3 15D 2,200 9,000 24,000 972,000 3,052,000,000

31

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) 32

Statistically inferred strategies



Value a sample of states empirically



Extrapolation

 Statistical methods, like linear regression    11111 = 1.00

11113 = .70

11112 = ?

33

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% 34

Explicitly Decomposed Methods



Combine values of dimensions and levels with specific assumptions

 Multi Attribute Utility Theory (MAUT) • Mutual utility independence • Structural independence 35

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) 36

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 37

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? 38

More health states, more assumptions



General public values at the most 50 states



The ratios empirical (50) versus extrapolated

 Rosser & Kind 1:1      EuroQol QWB SF-36 HUI (Mark III) 15D 1:5 1:44 1:180 1:19,400 1:610,000,000 

What is the critical ratio for a valid validation?

39

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

40

Conflicting evidence sensitivity SF-36 Liver transplantation, Longworth et al., 2001

41

Conclusions



More states



better sensitivity



The three leading questionnaires

 have different strong and weak points 42

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 43

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 44

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

Normal health

X

Dead

45

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

46

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

47

Consistent picture of difference

1.0

0.9

0.8

0.7

0.6

0.5

0.4

0.3

0.2

0.1

0.0

103 students

SG TTO VAS 12 11 1 11 21 1 21 11 1 11 12 1 11 11 2 11 12 2 32 21 1 21 23 2 33 32 1 22 32 3 22 23 3 33 33 3

EQ-5D health states

48

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

49

Little difference between Cost/Life Year and Cost/QALY Richard Chapman et al, 2004, Health Economics

50

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.” 51

QALYs make a difference when:



Chronic disease



Palliative



Long term negative consequences

52

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 53