HAC Cost-Effectiveness Analysis 3 — Questions and Answers
Question 1: Net Monetary Benefit (NMB) is calculated as:
- ICER × number of QALYs gained minus total cost
- (Willingness-to-pay threshold × incremental QALYs) − incremental costs (Correct answer)
- Total benefit in dollars minus total program cost
- Cost per QALY divided by the WTP threshold
Correct answer: (Willingness-to-pay threshold × incremental QALYs) − incremental costs
NMB converts health outcomes to monetary units using the WTP threshold and subtracts incremental costs; positive NMB indicates cost-effectiveness.
Question 2: A 'dominated' intervention in CEA is one that is:
- More costly and more effective than the comparator
- Less costly and less effective than the comparator
- More costly and less effective than the comparator (Correct answer)
- Less costly and more effective than the comparator
Correct answer: More costly and less effective than the comparator
A dominated intervention costs more and produces worse health outcomes than its comparator, making it irrational to choose.
Question 3: Extended dominance occurs when an intervention is ruled out because:
- Its ICER exceeds the WTP threshold
- A combination of two other interventions produces better outcomes at lower cost (Correct answer)
- It has higher costs and lower QALYs than a single alternative
- Its uncertainty intervals overlap with the comparator
Correct answer: A combination of two other interventions produces better outcomes at lower cost
Extended dominance eliminates an option whose ICER is higher than that of a more effective alternative, making a linear combination preferable.
Question 4: In healthcare CEA, the standard discount rate recommended by the US Panel on Cost-Effectiveness is:
- 0% for costs, 5% for outcomes
- 3% for both costs and health outcomes (Correct answer)
- 5% for costs, 3% for outcomes
- 10% for costs, 0% for outcomes
Correct answer: 3% for both costs and health outcomes
The 2nd US Panel on Cost-Effectiveness in Health and Medicine recommends a 3% annual discount rate for both costs and health outcomes.
Question 5: What is the primary advantage of using QALYs over life-years gained as an outcome measure in CEA?
- QALYs are easier to measure directly in clinical trials
- QALYs incorporate both length and quality of life, enabling cross-disease comparisons (Correct answer)
- QALYs require no utility weighting and are therefore more objective
- QALYs eliminate the need for a discount rate in long-term models
Correct answer: QALYs incorporate both length and quality of life, enabling cross-disease comparisons
QALYs combine survival duration with health-related quality of life, allowing comparison of interventions across different disease areas.
Question 6: Which instrument is commonly used to derive EQ-5D utility values for QALY calculation?
- SF-36
- EQ-5D questionnaire with population-based value set (Correct answer)
- Visual Analog Scale administered by clinicians
- Hospital Anxiety and Depression Scale
Correct answer: EQ-5D questionnaire with population-based value set
The EQ-5D is a standardized instrument whose dimension scores are mapped to utility values using population preference-based value sets.
Question 7: Time trade-off (TTO) is a method used to:
- Measure how long patients wait for treatment in different healthcare systems
- Elicit health state utility values by asking individuals how much life they would trade for perfect health (Correct answer)
- Calculate the discounted value of future health benefits
- Estimate transition probabilities between disease states
Correct answer: Elicit health state utility values by asking individuals how much life they would trade for perfect health
TTO elicits utility values by asking respondents to choose between living in a health state for a defined period versus fewer years in perfect health.
HAC Cost-Effectiveness Analysis 3
Net Monetary Benefit (NMB) is calculated as: