economic evaluation

Economic EvaluationEconomic Evaluation

Ken SteinPublic Health Physician

North & East Devon Health Authority

University of Exeter

QuestionsQuestions

• 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

EBM

Policy

Audit

Development

A national problemA national problem• Higgenbottom’s 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

Economic analysis involves 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

Spotting economic analysesSpotting 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

CHOICE

TreatmentA

TreatmentB

Consequences

Consequences

PERSPECTIVE ...PERSPECTIVE ...

Types of economic analysisTypes of economic analysis

• Cost minimisation

• Cost effectiveness

• Cost utility

• Cost benefit

Costs Outcomes? Type of analysis£ Identical Cost minimisation£ Same type:Natural units

– life years gained,mmHg changeDifferent amounts

Cost effectiveness

£ QALYs Cost utility£ £ Cost benefit

Defining economic analysesDefining economic analyses

Cost effectivenessCost 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

Alternativeless effective and more costly E

Alternativecheaper but lesseffective

D

Alternativemore effective and less costly

C

E.g. £20,000per QALY

COST

OUTCOMEA

B

Alternative more effectivebut more costly

Marginal (Marginal (syn: syn: incremental) incremental) or average analysis?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 it’s probably worth giving 80mg where possible as the extra LYG costs only £10,000?

• Well...

COST

LYG

£25,000/LYG

£15,000/LYG

£85,000/LYG

80mg

40mg

Marginal cost effectiveness = what’s the extra cost to get the extra effectiveness?

i.e. Difference in costs Difference in effectiveness

Quality Adjusted Life YearsQuality 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

QALY burden of HSQALY 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

Utilities and QALYsUtilities 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

QALY gains - exampleQALY gains - example

QALYs - patient 1

QALYs - patient 2

QALYs gained

Death Death

1.0

0

LYG gained

Utitilies and HSUtitilies 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 impotenceused in an evaluation of the cost utility of viagra

The NICE appraisalThe NICE appraisal

• Was a well defined question posed?

• TITLE: Cost effectiveness and Cost Utility of Ballet Therapy for Higginbottom’s 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

Was a comprehensive Was a comprehensive description of competing description of competing

alternatives given?alternatives given?

• Intervention: Fonteyn’s model for ballet therapy

• Comparator: do nothing

Was the analysis based on Was the analysis based on valid evidence?valid evidence?

• Fonteyn M et al. 2000

• five year RCT of Ballet therapy for HS

• Number of fights prevented = 13 per year

Were all important and Were all important and relevant resources identified relevant resources identified

for each alternative?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

Results 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

ResultsResults COST

OUTCOME

Cost per fight averted = £744

ResultsResults COST

OUTCOME

Cost per QALY = £41,230

£20,000per QALY

Were healthcare use and Were healthcare use and health outcome health outcome

consequences adjusted for consequences adjusted for the different times at which the different times at which

they occurred? 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 @ 6%Year 1 = £1000Year 2 = £943Year 3 = £890Year 4 = £840Year 5 = £792TOTAL = £4,465

Was an adequate sensitivity Was an adequate sensitivity analysis performed?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

Will the results help you?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?

Appraisal decisionAppraisal 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