Download - 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