PEBC MCQ Evidence-based Practice & Drug Information question: antihypertensives for stroke prevention reports a hazard ratio

PEBC MCQEvidence-based Practice & Drug Information

A trial comparing two antihypertensives for stroke prevention reports a hazard ratio of 0.88 with a 95% confidence interval of 0.74 to 1.05. Which of the following is the most appropriate interpretation?

a. The difference between the drugs is not statistically significant at the 5% level.
b. The new drug reduced strokes by 12% compared with the other drug, a statistically significant benefit.
c. The new drug increased stroke risk by up to 5% compared with the comparator.
d. The result is significant because the point estimate lies below 1.0.

Show the answer and explanation

Answer: a. The difference between the drugs is not statistically significant at the 5% level.

For a ratio measure, a 95% confidence interval that includes 1.0 (no difference) means the result is not statistically significant at p < 0.05. Here 0.74 to 1.05 crosses 1.0, so the trial is compatible with up to a 26% reduction or a 5% increase in risk. The point estimate of 0.88 alone cannot establish significance; the interval must exclude 1.0. Source: Guyatt G et al. Users' Guides to the Medical Literature, 3rd ed. (2015), ch. 10 Confidence intervals; Cochrane Handbook for Systematic Reviews of Interventions, version 6.5 (2024), ch. 15.

Common mistake

Judging significance from the point estimate rather than from whether the interval crosses the line of no effect.

Practice more PEBC MCQ Evidence-based Practice & Drug Information questions

Exam-style questions with worked answers, then full timed mocks. Free to start.

Start practicing →

Study note: Evidence-based Practice & Drug Information PEBC MCQpractice questions & mock exams

Related PEBC MCQ practice questions

In a 3-year randomized trial, stroke occurred in 12% of patients given placebo and in 8% of patients given a new anticoagulant. How many patients must be treated for 3 years to prevent one stroke?In a 12-week trial, clinically significant hyperkalemia occurred in 6% of patients taking a mineralocorticoid receptor antagonist and in 2% of those taking placebo. What is the number needed to harm over 12 weeks?PK is a 52 year old male newly diagnosed with hypertension after home monitoring averaged 148/94 mm Hg. He has no other medical conditions and takes no medications. According to Hypertension Canada's 2025 primary care guideline, which initial treatment is most appropriate?

Build a daily practice habit — a few exam-style questions a day, with worked answers. Free to start.

Start practicing →

Original practice material written to the public PEBC blueprint; not a past or real exam question. Not affiliated with or endorsed by The Pharmacy Examining Board of Canada (PEBC). Educational practice material for exam preparation only. Not medical advice and not a substitute for current product monographs, clinical guidelines or professional judgement. Questions have not yet been reviewed by a licensed pharmacist.