BCACP Clinical Literature Interpretation 2 ā Questions and Answers
Question 1: A randomized controlled trial reports a relative risk reduction (RRR) of 30% for a primary endpoint. The control event rate is 5%. What is the absolute risk reduction (ARR)?
- 1.5% (Correct answer)
- 30%
- 5%
- 25%
Correct answer: 1.5%
ARR = RRR Ć control event rate = 0.30 Ć 5% = 1.5%.
Question 2: Which statistical test is most appropriate for comparing means across three or more independent groups in a clinical trial?
- One-way ANOVA (Correct answer)
- Paired t-test
- Chi-square test
- Pearson correlation
Correct answer: One-way ANOVA
One-way ANOVA compares means among three or more independent groups simultaneously.
Question 3: A study uses an intention-to-treat (ITT) analysis. Which statement best describes this approach?
- All randomized patients are analyzed in their originally assigned groups regardless of protocol adherence (Correct answer)
- Only patients who completed the study are included
- Patients are analyzed based on the treatment they actually received
- Dropouts are excluded from the final analysis
Correct answer: All randomized patients are analyzed in their originally assigned groups regardless of protocol adherence
ITT preserves randomization by analyzing all participants in their originally assigned groups, minimizing bias.
Question 4: A meta-analysis reports an IĀ² statistic of 75%. How should this be interpreted?
- High heterogeneity exists among the included studies (Correct answer)
- 75% of studies show statistical significance
- The pooled effect is highly precise
- Low heterogeneity exists among the included studies
Correct answer: High heterogeneity exists among the included studies
An IĀ² of ā„75% indicates substantial heterogeneity, questioning the validity of pooling results.
Question 5: In a pharmacokinetic study, which parameter best describes the rate of drug elimination?
- Elimination half-life (Correct answer)
- Volume of distribution
- Bioavailability
- Area under the curve (AUC)
Correct answer: Elimination half-life
Elimination half-life reflects the time required to reduce plasma drug concentration by 50%, representing elimination rate.
Question 6: A clinical trial reports a p-value of 0.04 with a pre-specified alpha of 0.05. Which conclusion is correct?
- The result is statistically significant; the null hypothesis is rejected (Correct answer)
- The result is clinically significant
- The null hypothesis is accepted
- The result is not statistically significant
Correct answer: The result is statistically significant; the null hypothesis is rejected
A p-value below the pre-specified alpha (0.04 < 0.05) leads to rejection of the null hypothesis.
Question 7: Which type of bias occurs when patients and investigators both know the treatment assignment in a clinical trial?
- Performance bias (Correct answer)
- Attrition bias
- Detection bias
- Selection bias
Correct answer: Performance bias
Performance bias results from differential care or behaviors when treatment allocation is unmasked to both participants and caregivers.
BCACP Clinical Literature Interpretation 2
A randomized controlled trial reports a relative risk reduction (RRR) of 30% for a primary endpoint.
The control event rate is 5%.
What is the absolute risk reduction (ARR)?