FREE UWorld Evidence-Based Content Questions and Answers
A randomized controlled trial (RCT) studying the effectiveness of a new antihypertensive drug reports a relative risk (RR) of 0.75 (95% CI: 0.60–0.90, 𝑝<0.05). What does this finding suggest?
The relative risk of 0.75 means that patients taking the drug have a 25% lower risk of hypertension-related events compared to those not taking the drug (1−0.75=0.25). The 95% confidence interval does not cross 1, and the 𝑝<0.05, indicating statistical significance.
According to current guidelines, what is the first-line treatment for a 55-year-old male with newly diagnosed Stage 1 hypertension and no other comorbidities?
For Stage 1 hypertension (systolic BP 130–139 mmHg or diastolic BP 80–89 mmHg) without additional cardiovascular risk factors, the first step is non-pharmacological interventions like diet, exercise, weight loss, and sodium reduction. Medications may be considered if BP remains elevated despite lifestyle changes.
In evidence-based practice, what is the primary purpose of a likelihood ratio in diagnostic testing?
Likelihood ratios (LR) combine sensitivity and specificity to estimate how much a test result will change the pre-test probability of a condition into the post-test probability. 𝐿𝑅+>1 increases the likelihood of disease, while 𝐿𝑅−<1 decreases it.
A cohort study observes that patients who exercise regularly have a lower incidence of diabetes. Which of the following is true about this type of study?
Cohort studies are observational studies where researchers follow groups with different exposures (e.g., regular exercise) over time to measure outcomes (e.g., diabetes incidence). They cannot establish causality and are less controlled than RCTs.
A 40-year-old smoker is counseled on lung cancer prevention. What is the most effective intervention to reduce their risk of lung cancer?
Smoking cessation is the single most effective intervention for reducing lung cancer risk. Screening (e.g., low-dose CT) is recommended for high-risk groups but does not reduce risk—it facilitates early detection.