Calculations Flashcards
What is the basic premise of economic evalution of a new healthcare intervention?
Compare the increase/ decrease in cost of the new treatment over the current and compare this to the difference in benefits.
How is the incremental cost calculated?
Cost of intervention 1- intervention 2/ benefits 1 -2.
E.g. Intervention 1 costs £100,000 and 500 people quit smoking, whereas intervention 2 costs £200,000 but 4000 people quit.
200,000-100,000/ 4000-500= £100,000 for an extra 3500 =incremental cost is £29 per extra quitter.
Different points of view of costing?
From healthcare point of view- only costs to the hospital/GP in terms of resources used, doctors/ nurse wages etc.
For societal point of view- also include personal costs to patients e.g. travelling to surgery, car parking, time off work etc.
Economic evalautions need which three aspects to be evaluated? Else are what? Give examples?
Examines costs, examines outcomes, compares to alternatives.
1. Only examines outcomes- if no comparison to alternative simply an outcome discription, if does compare then a RCT.
2. Examines costs only- no comparison= cost description, if comparison= cost evaluation.
3. Both but no comparison= cost-outcome evaluation.
With comparison= economic evaluation.
5 types of economic evaluation- v brief summary?
- Cost effectiveness Analysis (CEA)- on one outcome
- Cost utility Analysis (CUA)- QUALYs or DALYs
- Cost benefit Analysis (CBA)- costs and benefits in money terms
- Cost minimisation Analysis (CMA)- outcomes equal, compare costs only.
- Cost consequence analysis (CCM)- disaggreated outcomes.
What are the different denominators (bottom) of the economic evaluation calculations?
CEA: One health outcome in natural units e.g. lives saved, hospital admissions prevented.
CUA: QALYs or DALYs
CBA: Money saved by outcome
CMA: Nothing- assume is the same
CCA: all outcomes reported individually no calculation.
What is a cost effectiveness analysis (CEA)?
Cost/ one outcome measure.
Outcome is measured in natural units (interval properties e.g. 4 is double 2), and only one outcome is measured e.g. hospital visits avoided, lives saved- unless a multi-dimentional survey is used e.g. EQ5D.
Advantages of cost effectiveness analysis (CEA)?
- can answer technical efficiency questions if two interventions are for the same disease.
- Easy to understand by a lay person.
- simple to do, dont need to value the outcome as in for QALYs or monetary CBA.
Disadvantages of cost effectiveness analysis (CEA)?
- Unidimentional: Only use one outcome measure (unless survey- which needs lots of testing), so will likely miss a lot of the wider benefits.
- The outcome may have interval values (e.g. BP mmHg) but is the risk also linear to this? Likely after certain value higher benefit but this only says reduced by 10mmHg etc.
- Cannot compare interventions of different diseases as likely dont have the same outcome measure
- No sense of value to the outcome measures- cannot answer allocative questions at all.
What is a cost utility analysis (CUA)?
A special case of CEA, mainly used by NICE. Outcomes are all measured and valued in terms of healthy or disability life years- so this is a multidimentional measure of mortality and morbidity. If it is known how much the government is willing to pay per QALY (NICE £20-30,000) then can answer allocative questions. Utility is measured on a scale of 0-1.
Cost change/ QALY or DALY change- therefore get the additional price per QALY gained/ DALY averted.
What is a QALY?
The number of years lived in full health, e.g. if someone lives another 10 years and their QoL is 0.2, this would only be 2QALYs, but if was at 0.8 would be 8. So it is a measure of both extra life saved but also quality of life.
Utility: 0=as bad as dead, 1=full health.
Surveys can be used to estimate, that are either generic or specific to the disease- these take into account the patients health values if completed by them.
What is a DALY?
Disability adjusted life year- it is the opposite of QALY, so if 10 years at a QoL of 0.2 is 2 extra QALYs, it would be 8 DALYs (8 disabled years and 2 at full health)
Utility DALYs: 1=as bad as dead, 0=full health.
So, 1 year of health with a utility as bad as dead would equal 0 QALYs, but 1 DALY.
QALYs gained= DALYs averted.
QALY calculation:
Without an operation the patient would live another 2 years with a utility of 0.5.
With the operation, would live 5 years at 0.9.
QALYs gained from the operation?
Operation costs £3500?
Without: 2x0.5= 1 QALY
WIth: 5x 0.9=4.5 QALYs
Therefore, 3.5 QALYs are gained.
Say the operation costs £3500, that would be £1000 per QALY gained.
DALY calculation:
No operation health utility at 0.4 (disability state at 0.6) with 2 years to live, and a total of 3 life years lost.
Operation: a disability state of 0.1 for 5 years.
DALYs averted?
Without: (0.6x2)+(3x1)= 4.2
With: (0.1x 5)= 0.5
Therefore 4.2-0.5= 3.7 DALYs averted.
Advantages of Cost utility analysis CUA? (6)
- can use it for technical and allocative efficiency
- Easy comparuison between different diseases/ interventions.
- Considers morbidity as well as lives saved.
- can assess multiple outcomes and combine into quality of life
- Takes into account the patients values of health to work out their quality of life.
- Interval properties- can get info from RCTs easily.
Disadvantages of Cost utility analysis CUA? (5)
- Don’t know whether the QALY is made up of life years of qoL e.g. 2 QALYs is that 2 years at full health or 8 years at 0.25 health?
- How sensitive is this to changes?
- How to calculate how many years are lost for DALYs is hard- how do you know their life expectancy? Or QALys gained, have to estimate how long they would have lived etc.
- Linking public health society outcomes to QALYs is very hard.
- May miss other outcomes e.g. increase in productivity
What is Cost benefit analysis (CBA)?
Main method used by UK GOV, not just for health. Measures all outcomes in monetary terms, benefits are valued by the savings they generate.
In health terms some are easy e.g. loss of productivity- use their income to calculate, and fewer visits to the hospital, but what about valuing improved QoL for the patient?
Cost/savings
Two methods for valuing health for cost benefit analysis?
- Willingness to pay
2. Human capital approach
What is willingness to pay?
Used in CBA studies to value health. A description is given of lots of symptoms etc and the public says how much they would be willing to pay for treatment if that were them. Multiply the average spending by the no. of cases to get the money that should be spent.
This slightly takes into account the patients values, but often people have no concept of how much health costs.
What is the human capital approach?
Used in CBA studies to value health, through measuring it in terms of productivity. These years of life lost, or days of work are valued using the persons salary.
Ethical?
How to measure morbidity? Self confidence, pain etc
No patient values taken into account, but includes some societal impacts.
Advantages to cost benefit analysis? (5)
- Answers both technical and allocative questions
- Can include wider societal benefits e.g. crime, education.
- Can capture process utility (E.g. advantage to patient taking a pill once a week vs 3 times a day)
- Can capture externality e.g. can include benefit to others in the willingness to pay method.
- Can use for non-health interventions, so keeps it consistant between government departments.
Disadvantages to cost benefit analysis? (4)
- Ethics behind putting a monitary value on life, and boiling illness down to loss of productivity and therefore salary of that person- that person worth less if their salary is less? (human capital approach)
- how accurate is willingness to pay- in UK lack of concept of how much health costs.
- Human capital approach is incapable of valuing many healthcare benefits, or public health. e.g. pain, self esteem etc.
- does the CBA decision rule make sense in a budget confined system? E.g. people answer WTP based upon their individual incomes, but the health budget is not he countries total income combined, like say in private healthcare in the US.
What is Cost minimisation analysis? (CMA)
A comparison based upon incremental costs only, ‘assumes’ the outcomes are the same. E.g. two drugs with same effectiveness but different price- can work out the cost savings with one of the other.
E.g. two drugs, one injected at home, one IV. SC more expensive but dont need to have hospital costs? Assumed to be the same effectiveness- but are people more likely to be less complient at home etc.
Advantages of the cost minimisation analysis CMA? (2)
- Easy to do and understand
2. Useful for technical efficiency if are equivalent
