1 Interactive introduction in Quality of life Assessment Jan J. v. Busschbach, Ph.D. Department of Medical Psychology and Psychotherapy, Erasmus MC – Psychotherapeutic Centrum ‘De Viersprong’, Halsteren –

2 New cancer therapy SymptomsDrug XDrug Y Survival days Days sick of chemotherapy Days sick of disease TWiST

3 Time Without Symptoms of disease and subjective Toxic effects of treatment TWiST –Developed by Gelber (statistician) In search for a typical “cancer” problem –Often prolonged life but also a reductions in quality of life »At the beginning (side effects) »At the end –Only count the days without symptoms of disease and subjective toxic effects of the treatment

4 TWiST ignores differences in quality of life TWiST –Healthy = 1 –Sick (dead) = 0 There is more to life than sick/health –Make intermediate values –Q-TWiST »Quality of life adjusted adjusted TWiST How to scale quality of life? What is Quality of life?

Quality of life “…. Health is physical, mental and social well- being and not merely the absence of disease or infirmity...” –World Health Organization, 1947 Extending health to well-being: Quality of life What is the definition of quality of life?

Definitions of Quality of Life Quality of life is the degree of need and satisfaction within the physical, psychological, social, activity, material and structural area (Hörnquist, 1982). Quality of life is the subjective evaluation of good and satisfactory character of life as a whole (De Haes, 1988). Health related quality of life is the subjective experiences or preferences expressed by an individual, or members of a particular group of persons, in relation to specified aspects of health status that are meaningful, in definable ways, for that individual or group (Till, 1992). Quality of life is a state of well-being which is a composite of two components: 1) the ability to perform everyday activities which reflects physical psychological, and social well-being and 2) patient satisfaction with levels of functioning and the control of disease and/or treatment related symptoms (Gotay et al., 1992). An individual’s perception of their position in life in the context of the culture and values systems in which they live and in relation to their goals, expectations, standards and concerns (WHO Quality of life Groups, 1993).

No clear definition because: Many possible definitions –Multi-dimensionally –Subjective –Related to society Researchers are free to choose –The notion of measuring the quality of life could include the measurement of practically anything of interest to anybody. And, no doubt, everybody could find arguments supporting the selection of whichever set of indicators to be his choice (Andrews & Withy, 1976, page 6)

8 No clear definition because: Different origins of research –Clinical decision making: Does the patient benefit from the treatment? –Epidemiology (public health): what is the morbidity of the population? –Health economics: Is it worth the money?

Common items in definitions: 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. “ (Aaronson, in B Spilker (Ed): Quality of life and Pharmacoeconomics in Clinical Trails, 1996, page 180)

Common items in definitions: Health related Multidimensional –Physical, psychological, social Questionnaires –Standardize questions and response »Reproducible results: sciences »Quantify subjectivity Operational defined –Like IQ and temperature.

How to measure quality of life form a clinical point of view? Choose items –Are you able to walk one kilometer ? –Do you feel depressed ? Choose response mode –Binary yes / no –Multiple (Likert) yes / at bid / hardly / no –Continuous ( Visual Analogue Scale ) Always ————X—— Never Combine items to dimensions of quality of life –Sum up the items belonging to one dimension –Rescale sum on a scale from 0 to 100

12 Quality of life form a clinical point of view: profiles

13 Can profiles help? (1) SymptomsDrug XDrug Y Survival days Days sick of chemotherapy Days sick of disease TWiST

14 Can profiles help? (2) TWiST –Healthy = 1 –Sick (dead) = 0 There is more to life than sick/health –Make intermediate values –Q-TWiST »Quality of life adjusted adjusted TWiST How to scale quality of life? What is Quality of life?

15 How to scale QoL for Q-TWiST? One needs a uni-dimensional value of QoL –Like the IQ-test measures intelligence –Rules out multi-dimensional questionnaires Ratio or interval scale –Difference between 0 and.8 must be 8 time higher than.1 Four popular methods have these pretensions –Visual Analog Scale, Time Trade-Off, Standard Gamble, Person trade-off Plus validated questionnaires –HUI, EuroQol EQ-5D, 15-D, AQoL, etc

16 Value a health state You are in a wheelchair No pain or discomfort No psychosocial problems

17 Visual Analogue Scale VAS –Also called category scaling From psychological research “How is your quality of life today ?” “X” marks the spot –Response in centimeters –Rescale to [0..1] Dead Normal health X

18 Time Trade-Off TTO –Values Quality of Life in QALYs –Quality adjusted life years 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

19 Q-TWiST = QALY When health (QoL) is valued in years –instead of of days…. Q-TWiST = Quality Adjusted Life Years –QALYs Q-TWiST invention of physicians QALY invention of economists

20 Patient values include coping Stensman –Scan J Rehab Med 1985;17: Scores on a visual analogue scale –36 subjects in a wheelchair –36 normal matched controls Mean score –Wheelchair: 8.0 –Health controls: 8.3 The patient perspective does not work in Health economics Healthy Death

21 The general public should be informed… Valuing without knowledge makes no sense –Thyroid Eye Disease Give description of the disease A patient with bilateral thyroid eye disease with upper lid retraction and exophthalmos.

22 Which health care program is the most cost-effective? A new wheelchair for elderly –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

23 QALY league table

24 Implications shifting threshold QALY are weighted Weighted QALYs are maximized –Health is no longer the only thing maximized Health status population will drop Differences in health will drop –Egalitarian consideration are incorporated Burden of disease becomes a criteria

25 Shifting threshold

26 Practice

27 CE-ratio by equity

28 Conclusions Quality of life can be valued in –Profiles »Psychometric approach –Unidimensional scaling »Health economics Different perspective –Societal –Patient »Coping Quality of life definition –Operational defined Quality of life can moderate cost-effectiveness