FPGEE Biostatistics 5

Question 1

In a pharmacoeconomic study, incremental cost-effectiveness ratio (ICER) is calculated as $80,000 per QALY. Using the commonly cited US willingness-to-pay threshold, how should this be classified?

Accepted Answer

Borderline cost-effective

Answer

The conventional US WTP threshold is approximately $50,000–$150,000 per QALY; $80,000/QALY falls within this range, making it borderline or acceptable.

Question 2

In a cohort study, person-years are used as the denominator for incidence rates. Why is this approach used?

Accepted Answer

It accounts for varying lengths of follow-up among participants

Answer

Person-years of observation account for the fact that participants may enter or exit the study at different times, ensuring the denominator reflects actual time at risk.

Question 3

A publication reports a forest plot in which most individual study confidence intervals overlap zero, but the pooled diamond does not touch zero. What is the most accurate interpretation?

Accepted Answer

The pooled analysis has sufficient power to detect a statistically significant overall effect

Answer

Pooling studies in meta-analysis increases effective sample size, giving the pooled estimate greater power to detect effects that individual underpowered studies could not.

Question 4

A researcher wants to assess agreement between two pharmacists measuring pill-cutting accuracy using a continuous scale. Which statistical method is most appropriate?

Accepted Answer

Bland-Altman plot and limits of agreement

Answer

The Bland-Altman method assesses agreement between two measurement methods by plotting the difference against the mean, revealing systematic bias and variability.

Question 5

Cox proportional hazards regression produces a hazard ratio (HR) of 0.60 for a new antifungal vs. placebo (95% CI: 0.40–0.89). How should this be interpreted?

Accepted Answer

The new drug reduces the instantaneous risk of the event by 40% at any given time

Answer

HR < 1 means the treatment group has a lower instantaneous hazard; HR = 0.60 means a 40% reduction in the hazard of the event at any point in time.

FPGEE Exam Practice Test

FPGEE Exam Practice Test

FPGEE Biostatistics 5