Economic Evaluation

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Economic Evaluation

• Ken Stein
• Public Health Physician
• North East Devon Health Authority
• University of Exeter

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Questions

• Can it work?
• Efficacy
• Does it work?
• Effectiveness
• Should it be used, given other calls on a fixed
  budget?
• Economics
• Is it reaching those whom it should?
• Availability

Development
EBM
Policy
Audit
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A national problem

• Higgenbottoms syndrome is now recognised as a
  national problem
• There are grave concerns about a lottery of
  postcode dancing
• NICE takes action...
• Your PCT is not convinced and asks you to review
  the evidence
• You need some background to deal with the results
  of your search and the NICE evaluation

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Economic analysis involves

• Identification of alternatives
• their consequences
• and their costs
• the values of these
• and how they compare
• to inform the decision on whether you should do
  it

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Spotting economic analyses

• Is there a comparison of two or more
  alternatives?
• Are both costs and consequences examined?
• If not - the study is not an economic evaluation
  but may be
• description of costs or outcomes
• evaluation of efficacy or effectivenes
• cost analysis

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Consequences
Treatment A
Costs
PERSPECTIVE ...
CHOICE
Consequences
Treatment B
Costs
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Types of economic analysis

• Cost minimisation
• Cost effectiveness
• Cost utility
• Cost benefit

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Defining economic analyses
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Cost effectiveness

• How much it costs to get an effect
• e.g. how much per fight prevented by ballet
  therapy?
• i.e the RATIO of COSTS to EFFECTS
• How might different cost effectiveness ratios for
  alternative treatments appear?
• The cost effectiveness plane

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COST
A
OUTCOME
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Marginal (syn incremental) or average analysis?

• An analysis of different doses of a cholesterol
  lowering drug shows that 80mg per day gives a
  cost effectiveness of 25,000 per life year
  gained (LYG)
• 40mg per day gives 15,000 per LYG
• So its probably worth giving 80mg where possible
  as the extra LYG costs only 10,000?
• Well...

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25,000/LYG
85,000/LYG
15,000/LYG
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Marginal cost effectiveness whats the extra
cost to get the extra effectiveness?
i.e. Difference in costs Difference in
effectiveness
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Quality Adjusted Life Years

• A 1985, good quality, 10 year cohort study of HS
  showed
• Life expectancy is reduced by one year compared
  to national life tables
• HS sufferers spent, on average
• 120 person days per year with
• limited mobility
• episodic incontinence
• moderate pain
• depression of mood

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QALY burden of HS

• 100 people with HS will, over 10 years
• lose 100 life years
• lose 100 x 0.3 years of full quality of life

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Utilities and QALYs

• Utility is a measure of preference about an
  outcome (a health state), giving an indication of
  the relative value placed on the health state
• Scaled 0 (death) to 1 (full health)
• Utilities are used to weight time according to
  quality of life spent during that time
• A health state with a utility of 0.5 lasting two
  years is equivalent to one year in full health
• Allows us to consider differences in treatments
  which involve changes in quality as well as
  quantity of life

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QALY gains - example
QALYs gained
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Utitilies and HS

• Description of HS health states to experts for
  opinion (Dr Phillips says utlity 0.95)
• Eliciting utilities with HS sufferers
• Visual analogue scale
• Time trade off (utility 0.67)
• Standard Gamble
• Mapping onto health state measures for which
  preferences are known e.g. EQ5D
• Mobility
• Self-care
• Usual activity (utility 0.85)
• Pain / discomfort
• Anxiety / depression

PS - these are the real values for utilities
associated with impotence used in an evaluation
of the cost utility of viagra
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The NICE appraisal

• Was a well defined question posed?
• TITLE Cost effectiveness and Cost Utility of
  Ballet Therapy for Higginbottoms Syndrome - a
  report to NICE, January 2001
• Perspective was the NHS, with potential impacts
  on non-health sector identified but not included
  in the analysis

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Was a comprehensive description of competing
alternatives given?

• Intervention Fonteyns model for ballet therapy
• Comparator do nothing

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Was the analysis based on valid evidence?

• Fonteyn M et al. 2000
• five year RCT of Ballet therapy for HS
• Number of fights prevented 13 per year

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Were all important and relevant resources
identified for each alternative?

• Costs
• Ballet therapy - GP, specialist community dancing
  support team, capital for ballet schools, trainer
  costs, follow up, replacement dresses.
  Identified from micro-costing study
• Savings
• Healthcare costs associated with HS, estimated
  from National reference costs for HRGs
• Outcomes
• Number of fights
• QALYs based on healthstates associated with
  fights and treatment, valued by expert opinion

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Results

• Ballet therapy costs an average of 14,756 per
  year
• Savings to the NHS 4,875 per year
• Total costs to the NHS of implementing ballet
  therapy would be 483m over 5 years
• Incremental benefits would be
• 13 fights prevented
• 0.24 QALYs gained

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Results
COST
Cost per fight averted 744
OUTCOME
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Results
COST
Cost per QALY 41,230
OUTCOME
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Were healthcare use and health outcome
consequences adjusted for the different times at
which they occurred?

• Undiscounted
• Year 1 costs 1,000
• Year 2 costs 1,000
• Year 3 costs 1,000
• Year 4 costs 1,000
• Year 5 costs 1,000

Discounted _at_ 6 Year 1 1000 Year 2
943 Year 3 890 Year 4 840 Year 5
792 TOTAL 4,465
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Was an adequate sensitivity analysis performed?

• One way sensitivity analysis on costs and
  outcomes (number of fights, utilities associated
  with health states) showed results reasonably
  stable
• Cost effectiveness 530 to 2400 / FP
• Cost utility 35,000 to 56,000 per QALY (over 5
  years - no modelling beyond the end of the trial
  undertaken)
• Dress and ballet trainer costs were most
  influential in the sensitivity analysis

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Will the results help you?

• Were the conclusions justified?
• Can the results be applied to your population?
• Effectiveness of ballet therapy?
• Implementation costs different (shortage or
  excess of ballet trainers, availability of
  dresses, dispersed population)?
• Costs of healthcare (savings) different?
  Organisation of the healthcare system?
• Discounting rate may differ?

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Appraisal decision

• Ballet therapy is an effective treatment but
  benefits are modest compared to other calls on
  the NHS budget. Considerable uncertainty
  remains over the long term effects of ballet
  therapy and further research is required,
  incorporating an economic analysis from a
  broader societal perspective
• The International Confederation of Ballet
  Trainers has contested this decision