BCACP Clinical Literature Interpretation 5 — Questions and Answers
Question 1: In a survival analysis, which graphical method is used to display time-to-event data comparing two treatment groups?
- Kaplan-Meier curve (Correct answer)
- Forest plot
- Funnel plot
- Box-and-whisker plot
Correct answer: Kaplan-Meier curve
Kaplan-Meier curves display the probability of survival over time and allow visual comparison between groups.
Question 2: A study applies Bonferroni correction when analyzing multiple secondary endpoints. What is the purpose of this adjustment?
- To control the family-wise Type I error rate when performing multiple comparisons (Correct answer)
- To increase statistical power for each comparison
- To reduce Type II error across all endpoints
- To adjust for confounding variables
Correct answer: To control the family-wise Type I error rate when performing multiple comparisons
Bonferroni correction divides the alpha level by the number of comparisons to reduce the chance of false positive results.
Question 3: A funnel plot in a meta-analysis is asymmetrical. This finding most likely indicates:
- Publication bias may be present (Correct answer)
- High heterogeneity among included studies
- The meta-analysis included too few studies
- The pooled effect is not statistically significant
Correct answer: Publication bias may be present
Asymmetry in a funnel plot suggests smaller studies with negative results may not have been published, indicating publication bias.
Question 4: Which of the following best defines a surrogate endpoint?
- A biomarker used as a substitute for a clinically meaningful outcome (Correct answer)
- A secondary endpoint pre-specified in the protocol
- The primary outcome measured in a trial
- An endpoint used only in pharmacokinetic studies
Correct answer: A biomarker used as a substitute for a clinically meaningful outcome
Surrogate endpoints are biomarkers (e.g., HbA1c, LDL-C) assumed to correlate with clinical outcomes but may not capture true patient benefit.
Question 5: A pharmacist critically evaluates a trial and notes patients in the control group received standard care instead of placebo. This describes which control type?
- Active comparator control (Correct answer)
- Placebo control
- No-treatment control
- Wait-list control
Correct answer: Active comparator control
An active comparator control compares the new intervention to existing standard-of-care treatment rather than an inert placebo.
Question 6: In a clinical trial, which measure quantifies the variability of the sample mean and indicates the precision of the estimate?
- Standard error of the mean (SEM) (Correct answer)
- Standard deviation (SD)
- Interquartile range (IQR)
- Coefficient of variation (CV)
Correct answer: Standard error of the mean (SEM)
SEM reflects how precisely the sample mean estimates the population mean and decreases as sample size increases.
Question 7: A pharmacist interprets a hazard ratio (HR) of 0.72 (95% CI 0.55–0.94) from a time-to-event analysis. What is the correct interpretation?
- The treatment group had a 28% lower rate of the event compared to control at any given time point (Correct answer)
- The treatment group had a 72% higher event rate than control
- The treatment delayed the event by 28 days on average
- The result is not statistically significant because HR < 1
Correct answer: The treatment group had a 28% lower rate of the event compared to control at any given time point
An HR of 0.72 means the instantaneous event rate in the treatment group is 28% lower than in the control group throughout follow-up.
BCACP Clinical Literature Interpretation 5
In a survival analysis, which graphical method is used to display time-to-event data comparing two treatment groups?