Game 21 · Public health and research practice
Which treatment gives the most health for the money?
QALY, DALY, cost-effectiveness and the ICER.
20 DNB questions
Play
Spend a made-up health budget
Each round asks a question a budget holder faces. Work out an ICER and decide against the threshold the round gives you, place a new option on the cost-effectiveness plane, count QALYs and DALYs, or name the type of economic evaluation. You have three lives.
Loading the first round…
Every intervention, cost, utility, disability weight, life expectancy and threshold in the game is made up for teaching.
Four types
What is compared with the cost decides the type of evaluation
All four types compare the costs of two or more options with their consequences. They differ in how the consequences are measured (HTAIn Manual, Department of Health Research, 2018).
| Type | Consequences measured as | Result | Example |
|---|---|---|---|
| Cost-minimisation | Assumed the same for all options | The cheapest option | Two antibiotics with equal cure rates |
| Cost-effectiveness | Natural units: mm Hg, cases detected, life-years gained | Cost per unit of effect | Cost per TB case detected |
| Cost-utility | QALYs (DALYs are also used) | Cost per QALY gained | Cost per QALY of a cancer drug |
| Cost-benefit | Money | Net benefit in rupees | A water purification scheme |
| Feature | Cost-effectiveness | Cost-benefit |
|---|---|---|
| Outcome | A health unit (mm Hg, cases, life-years) | Rupees |
| Answers | Which option buys a unit of health more cheaply? | Do the benefits exceed the costs? |
| Compares across programmes | Only those with the same outcome unit | Any, since everything is in money |
| Main difficulty | One outcome may not capture all effects | Putting a money value on health |
ICER
The extra cost of each extra unit of health
ICER = (Cost new − Cost old) ÷ (Effect new − Effect old)
- Cost
- cost per patient of each option
- Effect
- health gained per patient, for example QALYs
The cost-effectiveness plane (Black, Med Decis Making 1990) puts the difference in effect on the x-axis and the difference in cost on the y-axis. South-east (more effective, less costly): the new option dominates. North-west (more costly, less effective): it is dominated. North-east and south-west are trade-offs, judged by comparing the ICER with a threshold.
Thresholds. WHO-CHOICE (2005) called an intervention very cost-effective below one times per-capita income per DALY averted, and cost-effective below three times. The HTAIn manual quotes these but says they should not be used alone as a justification for funding. HTAIn studies compare results with one times India's GDP per capita per QALY, and the manual notes that the HTA board has not been explicit about a threshold. The thresholds in this game are set by the round, not taken from any official rule.
QALY and DALY
Two ways to count healthy time
QALYs = Σ (utility × years in that health state)
- Utility
- 0 = dead, 1 = full health
DALY = YLL + YLD
- YLL
- years of life lost: deaths × standard life expectancy at the age of death
- YLD
- years lived with disability: prevalent cases × disability weight
Since the Global Burden of Disease 2010 study, DALYs are calculated with no age-weighting and no discounting, and YLD is based on prevalence rather than incidence (Murray and colleagues, Lancet 2012). WHO adopted the same approach for its Global Health Estimates. Older textbooks still describe the earlier method with age-weighting and discounting.
| Feature | DALY | Years of potential life lost (YPLL) |
|---|---|---|
| Counts | Years lost to early death and years lived with disability | Years lost to early death only |
| Cut-off | Standard life expectancy at each age, no arbitrary cut-off | A set end point, commonly 65 years or life expectancy |
| Deaths counted | All deaths | Only deaths before the end point |
Writing the answer
How to write this in a 10-mark DNB answer
- Define economic evaluation as a comparison of the costs and consequences of two or more options.
- Draw the table of the four types, with how consequences are measured and one example each.
- For cost-effectiveness versus cost-benefit, give a head-to-head table like the one above.
- Write the ICER formula, draw the cost-effectiveness plane with its four quadrants and a threshold line, and say what dominant and dominated mean.
- For DALY or QALY questions: give the formula, a worked example with round numbers, and state that GBD dropped age-weighting and discounting from 2010.
- End with the Indian context: HTAIn in the Department of Health Research, and no legislated threshold.
The one thing to remember
Cost-effectiveness asks what each extra unit of health costs. The answer is useful only against a threshold someone is willing to pay.
Past papers
DNB questions this game helps you answer
Questions from NBE theory papers for DNB, DrNB and Diploma courses, most often asked first. The tag after each question is the specialty and the year it was set.
- ×2Disability Adjusted Life Years (DALY).
- ×1Outline the factors you would consider in making a cost-benefit analysis of introducing a new component of care into your Intensive Care Unit.
- ×1Cost Effectiveness & Cost benefit analysis.
- ×1Cost effectiveness analysis in Rehabilitation Medicine.
- ×1Difference between Cost-Benefit Analysis and Cost-Effectiveness Analysis.
- ×1Disability adjusted life Years (DALY’s).
- ×1Define catastrophic health expenditure. Describe the broad types of economic evaluation relevant to health programs.
- ×1Disability adjusted life years (DALY’s) & Quality adjusted life years (QALY’s).
- ×1Cost benefit analysis and its application in medical care in hospital.
- ×1Problems in assessing the sensitivity and specificity of screening tests and cost benefit analysis of screening.
- ×1Cost Effectiveness Vs Cost Benefit.
- ×1Cost-effectiveness analysis and Cost-benefit analysis
- ×1Difference between cost benefit and cost effective analysis.
- ×1Disability Adjusted Life Years (DALYs).
- ×1How is DALYs different from Years of Potential Life Lost (YPLL)?
- ×1Quality Adjusted Life Years (QALYs).
- ×1Cost-Effective analysis.
- ×1In what ways it is different from Cost-Benefit analysis?
- ×1Cost effective and cost benefit analysis in health care.
- ×1Quality Adjusted Life Years (QALYS)