BCACP Clinical Literature Interpretation 4 — Questions and Answers
Question 1: A case-control study compares patients with type 2 diabetes (cases) to those without (controls) regarding past antipsychotic use. What is the most appropriate measure of association?
- Odds ratio (Correct answer)
- Relative risk
- Absolute risk reduction
- Incidence rate ratio
Correct answer: Odds ratio
Odds ratio is used in case-control studies because incidence rates cannot be directly calculated from this design.
Question 2: Which pharmacoeconomic analysis determines the cost per quality-adjusted life year (QALY) gained?
- Cost-utility analysis (Correct answer)
- Cost-effectiveness analysis
- Cost-benefit analysis
- Cost-minimization analysis
Correct answer: Cost-utility analysis
Cost-utility analysis incorporates patient preferences using QALYs to compare interventions.
Question 3: A forest plot in a meta-analysis shows most study diamonds to the left of the line of no effect. This suggests:
- The intervention reduces the outcome compared to control (Correct answer)
- The intervention increases the outcome compared to control
- There is significant heterogeneity
- The studies have high risk of bias
Correct answer: The intervention reduces the outcome compared to control
In a forest plot, estimates to the left of the null line indicate the intervention favors reduction of the measured outcome.
Question 4: An ambulatory care pharmacist evaluates a non-inferiority trial. What is the key element that defines whether non-inferiority was achieved?
- The confidence interval for the treatment difference must not exceed the pre-specified non-inferiority margin (Correct answer)
- The p-value must be less than 0.05
- The treatment shows superiority over placebo
- The hazard ratio must be greater than 1.0
Correct answer: The confidence interval for the treatment difference must not exceed the pre-specified non-inferiority margin
Non-inferiority is established when the upper confidence interval boundary does not cross the pre-defined non-inferiority margin.
Question 5: Which type of study is most susceptible to recall bias?
- Case-control study (Correct answer)
- Randomized controlled trial
- Prospective cohort study
- Crossover trial
Correct answer: Case-control study
Case-control studies rely on participants recalling past exposures, making them vulnerable to recall bias.
Question 6: A receiver operating characteristic (ROC) curve with an AUC of 0.50 indicates:
- The diagnostic test performs no better than chance (Correct answer)
- The test has perfect discriminatory ability
- The test has high sensitivity and low specificity
- The test has a 50% positive predictive value
Correct answer: The diagnostic test performs no better than chance
An AUC of 0.50 means the test cannot distinguish between patients with and without the condition better than random chance.
Question 7: A pharmacist assessing external validity of a trial considers which of the following?
- Whether the study population is representative of patients seen in the pharmacist's practice (Correct answer)
- Whether randomization was properly performed
- Whether blinding was maintained throughout the trial
- Whether the primary endpoint was pre-specified
Correct answer: Whether the study population is representative of patients seen in the pharmacist's practice
External validity (generalizability) relates to how well the study population reflects real-world patients the clinician treats.
BCACP Clinical Literature Interpretation 4
A case-control study compares patients with type 2 diabetes (cases) to those without (controls) regarding past antipsychotic use.
What is the most appropriate measure of association?