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Quality of life and Cost-Effectiveness

An Interactive Introduction

Prof. Jan J. v. Busschbach, Ph.D.Erasmus MC

Medical Psychology and PsychotherapyViersprong Institute for studies on Personality Disorders

I want to live in…

Land A Life expectancy 80 Quality of life 0.8 Cures common

diseases

Land B Life expectancy 78.8 Quality of life 0.75 Cures catastrophic

diseases

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I would spend money on…

High incidenceMany patientsHigh burden Genetic causeEffective

treatmentCurtain outcome

Low incidenceLimited patientsLow burdenBehavioral causeNon effective

treatmentUncertain outcome

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I would spend money on…

Low incidenceMany patientsHigh burden Genetic causeEffective

treatmentCurtain outcome

High incidenceLimited patientsLow burdenBehavioral causeNon effective

treatmentUncertain outcome

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New cancer therapy

Symptoms Drug X Drug Y

Survival days 300 400Days sick of chemotherapy 10 150Days sick of disease 100 30TWiST 190 220

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Time Without Symptoms of disease and subjective Toxic effects of treatment: TWiST

Richard Gelber statistician

Count … Days not sick from treatment Days not sick from disease

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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

TWiST Healthy = 1 Sick (dead) = 0

Q-TWiST• Quality of life adjusted TWiST

Make intermediate values• 1.0; 0.75; 0.50; 0.25; 0.00

How to scale quality of life?

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0.0 Q

uality of lif

e 1

.0

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Uni-dimensional scale

Quality of life World Health Organization, 1947 “…. Health is physical, mental and social well-being and not

merely the absence of disease or infirmity...”

But we need a uni-dimensional scale Like temperature IQ Depression scale School grad

So we need a overall judgment…

Generic QoL Questions (SF-36)

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Complex interpretation

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Weighted index

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Visual Analogue Scale

Does the scale fit Q-TWIST? Is 2 days 0.5 Q = 1 day 1.0 Q ?

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Dead

Normal health

X?=

Interval / Ratio scale

Ratio or interval scale Difference 0.00 and 0.80 must be 8 time higher than 0.10

Uncommon in psychology

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Time Trade-Off

Wheelchair With a life expectancy: 50 years

How many years would you trade-off for a cure? Max. trade-off: 10 years

QALY(wheel) = QALY(healthy) Y * V(wheel) = Y * V(healthy) 50 V(wheel) = 40 * 1.00

V(wheel) = 0.80

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Example Blindness Time trade-off value is 0.5 Life span = 80 years 0.5 x 80 = 40 QALYs

Quality Adjusted Life Years (QALY)

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0.00

1.00

X

Life years40 80

0.5 x 80 = 40 QALYs

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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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Q-TWiST = QALY

Several initiatives early seventies Epidemiologist and health economists

Part of QALY concept Quality Adjusted Life Years QALY = Q-TWiST

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Area under the curve

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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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www.ibotnow.com

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Segway Dean Kamen

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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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10.000 Citations in PubMed

0

200

400

600

800

1000

1200

1970 1980 1990 2000 2010 2020

Publ

icat

ions

1980[pdat] AND (QALY or QALYs)

Orphan drugs

Pompe disease Classical form: infants €232.699/QALY; adults €2.800.000 New estimates: 500.000/QALY; 17.000.000

Low cost effectiveness but… High burden Low prevalence Little own influence on disease High consensus in the field

• Coalition patient, industry, doctors and media• Low perceived incertainty

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…it must be that QALYs are invalid

We don’t like the results…

In the past, much criticism

Cohen CB. Quality of life and the analogy with the Nazis. Journal of Medicine and Philosophy 8: 113-35, 1983.

Criticism remains

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….the strictly fascist essence of those QALYs (so-called

Quality-Adjusted Life Years)…

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Chris Murray WHO avoided QALY

(read: disliked QALYs) (read disliked health economics)

But WHO in need of a measure of health…

Asked Havard… “Anything… but QALY”

Chris Murray School of Public Health

Worked outside Health economics Med Decision Making

DALY

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Burden of disease: QALY lost = DALY (Disability adjusted life year)

DALY

QALY

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1.0

0.0A B C

Hea

lthEgalitarian Concerns:

Burden of disease

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80

0A B C

Leve

nsja

e nCosts/QALY as indicator of solidarity

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60

40

20

€ 50.000

€ 30.000

€ 40.000

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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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Costs/QALY versus Burden of disease

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€ 80.000

€ 60.000

€ 40.000

€ 20.000

€ 0

Burden of disease

X

XX

XX

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Dutch Council for Public Health and Health Care (RvZ, 2006)

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QALY debate

Fairness is the issue in the QALY debate QALY measurement is the straw man

Complex metric discussion Most debate about quality of life assessment

QALY are seen as unfair But: QALYs are needed to operationalise fairness

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Conclusion

Quality of life can be measured Usual multidimensional Unidimensional: QALYs

QALYs can validly be use in cost effectiveness research

Burden of disease is also a criterion On need QALYs to measure burden