Health Outcomes For Economics Evaluations

Health Outcomes for Economics Evaluations 11th December 2017

Fatiha Shabaruddin (PhD, RPh, B.Pharm) Faculty of Medicine, University of Malaya [email protected] 1

Outcomes (Benefits) of Health Care  Benefits, outcomes and consequences refer to the effect of health care interventions on the patient, not the effect on the people providing the service

 Some examples of outcome measures (benefits) of health care interventions: •Reduction in severity of symptoms •Improvements in organ function •Number of cases diagnosed •Number of deaths avoided •Years of life gained •Improvements in quality of life 2

Health Outcomes used in economic evaluations  Main types of outcome measures (benefits) considered in economic evaluations are:

•Clinical effectiveness

•Quality-adjusted life-years

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Effectiveness •Effectiveness is the outcome of a health care intervention measured in natural units •Can use clinical indicators to measure effectiveness •Specific outcome measures: o Reduction in severity of flu symptoms o Number of Hepatitis C cases diagnosed o Number of diabetes patients treated o Number of cervical cancer cases avoided o Improvements in lung function •General outcome measures: o Life-years gained o Number of deaths avoided

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Effectiveness as an outcome measure •How can we measure the effectiveness of a primary care clinic health programme: for example a hypertension screening programme? o General outcome measures

o Specific outcome measures

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Effectiveness

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Source:http://images.slideplayer.com/18/5690892/slides/slide_9.jpg

Effectiveness: outcome of health care intervention measured in natural units

Challenges of using effectiveness as an outcome measure o Different patient populations o Different disease characteristics o Use of different outcome measures  Variations in the data used to compete for the same healthcare resources & budget

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Effectiveness

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Quality of Life •Many new interventions or medicines improves quality of life (QoL) rather than quantity of life (length of life) •QoL is a generic concept reflecting concern with the modification and enhancement of life attributes (for example physical, political, moral and social environment relating to the overall condition of a human life) •Many factors impact on QoL: o Functional o Social o Psychological o Cognitive o Subjective 9

Quality of Life •Measuring QoL is methodologically complex

Source: http://open.jorum.ac.uk/xmlui/bitstream/handle/123456789/801/Items/K203_5_section13.html

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Quality of Life

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Quality-adjusted life-years •Quality-adjusted life years (QALY) is an outcome measure for life expectancy adjusted for quality of life •QALY combines morbidity and mortality by including the change in the quantity and quality of life •The quality of life component included in QALY is in term of utility

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Utility •Utility is the value attached by an individual for: – a specific health status or a specific health outcome •Utility reflects the preferences individuals or society may have for any particular set of health outcomes •Utilities for health states are based on preferences for the different health states (the more preferred health states receive greater weight) •Utility is very subjective – Different individuals may attach different values (utility) to the same health state 13

Utility For example, imagine a health state of being unable to walk further than 1 kilometre a day. – A 30 year old person may attach a lower utility value for this than an 80 year old person

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Utility • Utility is anchored at 0 to 1 – with 0 indicating death and 1 being perfect health • Utility can be used: – with patients with different illnesses – to compare health outcomes of different patient groups and for different health care interventions

• How to measure utility – Direct methods • Visual analogue scale • Standard gamble • Time-trade off – Indirect methods • generic preference-based questionnaires such as EQ-5D 15

Measuring Utility: Visual Analogue Scale How do you feel today?

16 Source: http://ebn.bmj.com/content/12/4/102.extract

Measuring Utility: Visual Analogue Scale How do you think you would feel with congestive heart failure?

The difference is the utility lost due to congestive heart failure

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Measuring Utility: Standard Gamble

18 Source: http://pn.bmj.com/content/8/3/175.abstract

Measuring Utility: Standard Gamble Would you choose state A or B? State A (sure thing) Lifetime with congestive heart failure

State B (gamble) Lifetime in perfect health (10 years) p = 0.80

(10 year lifetime) p = 0.20

Immediate death from the intervention 19

Measuring Utility: Standard Gamble

20 Source: http://pn.bmj.com/content/8/3/175.abstract

Measuring Utility: Time Trade-Off Would you choose state A or B? State A

State B

•You have congestive heart failure •You are on medication, have limited mobility and various lifestyle restrictions •You will live 15 years in this health state

•You will have 5 years in perfect health

Time t is varied in State B for the trade-off At the point of indifference  t = value for state i

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Measuring Utility: Standard gamble & Time Trade-Off For SG: Probability p is varied At the point of indifference  p = value for state i For TTO: Time t is varied

The value for p or t obtained is then used in a mathematical equation to calculate utility

Source: http://www.ispor.org/news/articles/aug05/qaly.asp

At the point of indifference  t = value for state i

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Measuring Utility: Indirect method (questionnaire) •There are several questionnaires that use the indirect method (a.k.a generic preference-based measure) to measure utility •Examples of these questionnaires include: o EQ-5D o SF-6D o HUI •Once completed, a utility score is generated using an algorithm (adjusted for the values [preference] for different domains) - For EQ-5D, the algorithm (mathematical equation) is based on values that have been obtained from a sample of the 23 general public for the 5 domains

Measuring Utility: EQ-5D

24 Source: http://bmb.oxfordjournals.org/content/96/1/5.full

Source: http://www.jclinepi.com/article/S0895-4356%2898%2900103-6/abstract

Measuring Utility: SF-6D

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Quality-adjusted life-years • QALYs are calculated by: – multiplying the utility value (which reflects the ‘quality’ of being in the resulting health state from the intervention)

with – the years of life produced by the intervention (life-years gained) • Using the QALY as the measure of outcome allows decisionmakers to compare across different types of interventions for different clinical conditions 26

Quality-adjusted life-years • QALYs are calculated by multiplying the utility value with the life-years gained from a health care intervention

27 Source: https://www.google.com/imgres?imgurl=https://upload.wikimedia.org/wikipedia/commons/4/49/QALY_graph.png&imgrefurl=https://en.wikipedia.org/wiki/Quality-adjusted_life_year

Quality-adjusted Life Years

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Quality-adjusted life-years • QALYs are calculated by multiplying the utility value with the life-years gained from a health care intervention

29 Source:http://holisticpracticedevelopment.com/health-economics-101-quality-adjusted-life-years/

Quality-adjusted life-years • QALYs are calculated by multiplying the utility value with the life-years gained from a health care intervention

30 Source: http://www.qalibra.eu/guide/images/image007.jpg /

Quality-adjusted life-years Example of QALY calculations • Patient Thomas received a coronary artery bypass graft surgery (CABG) and was hospitalised for 1 month, after which he spends 3 months attending physiotherapy. • Patient Katie received a pharmacological intervention (medicine) and was on the drug for 6 months, after which she spends 4 months attending physiotherapy. • What are the QALYs for these patients for a year if the utilities for the health states are as below: – – – –

Utility while hospitalised: 0.4 Utility while on medication: 0.7 Utility while attending physiotherapy: 0.8 Utility after physiotherapy: 0.9 31

Useful references •Whitehead & Ali (2010) Health outcomes in economic evaluation: the QALY and utilities. British Medical Bulletin 96: 5–21 (DOI:10.1093/bmb/ldq033) •Gray, Clarke, Wolstenholme & Wordsworth (2010) Applied Methods of Costeffectiveness Analysis in Healthcare. Oxford University Press