Free UWorld Evidence-Based Content Questions and Answers — Questions and Answers
Question 1: 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 drug reduces the risk of hypertension-related events by 75%.
- The drug reduces the risk of hypertension-related events by 25%. (Correct answer)
- The drug increases the risk of hypertension-related events by 25%.
- The drug has no statistically significant effect.
Correct answer: The drug reduces the risk of hypertension-related events by 25%.
A relative risk (RR) of 0.75 means that the risk of hypertension-related events in the drug group is 75% of the risk in the control group. To find the percentage reduction in risk, subtract the RR from 1 (1 - 0.75 = 0.25). This indicates a 25% reduction in risk. The 95% confidence interval (0.60–0.90) does not include 1, and the p-value is less than 0.05, confirming that this reduction is statistically significant.
Question 2: 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?
- ACE inhibitors
- Beta-blockers
- Lifestyle modifications (Correct answer)
- Thiazide diuretics
Correct answer: Lifestyle modifications
According to current hypertension guidelines (e.g., ACC/AHA), for a patient with newly diagnosed Stage 1 hypertension and no other comorbidities, lifestyle modifications are the recommended first-line treatment. These include dietary changes, regular physical activity, weight management, and limiting alcohol intake. Pharmacological therapy is typically initiated if lifestyle changes are insufficient after a certain period or if the patient has higher risk factors or Stage 2 hypertension.
Question 3: In evidence-based practice, what is the primary purpose of a likelihood ratio in diagnostic testing?
- To calculate the probability of disease after testing (Correct answer)
- To determine the sensitivity of the test
- To compare the test to a gold standard
- To assess the reliability of the test over time
Correct answer: To calculate the probability of disease after testing
Likelihood ratios (LRs) are a key component in evidence-based practice for diagnostic testing. They quantify how much a positive or negative test result changes the probability of a disease. LRs are used to convert pre-test probability into post-test probability of disease, helping clinicians update their diagnostic certainty after a test is performed.
Question 4: 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?
- It can establish causality between exercise and diabetes prevention.
- It measures the incidence of diabetes in an exposed and unexposed group. (Correct answer)
- It is more expensive and time-consuming than randomized controlled trials.
- It eliminates confounding variables through randomization.
Correct answer: It measures the incidence of diabetes in an exposed and unexposed group.
A cohort study is an observational study design where a group of individuals (a cohort) is followed over time. Researchers compare the incidence of a specific outcome (like diabetes) between a group exposed to a factor (e.g., regular exercise) and a group not exposed. While cohort studies can identify associations and measure incidence, they do not involve randomization and therefore cannot definitively establish causality like randomized controlled trials.
Question 5: A 40-year-old smoker is counseled on lung cancer prevention. What is the most effective intervention to reduce their risk of lung cancer?
- Annual low-dose CT screening
- Smoking cessation (Correct answer)
- Increasing physical activity
- Dietary supplementation with antioxidants
Correct answer: Smoking cessation
Smoking is the leading preventable cause of lung cancer and many other serious health conditions. For a smoker, the single most effective intervention to significantly reduce their risk of lung cancer and improve overall health is to quit smoking. While other interventions like screening or diet can play a role, addressing the primary risk factor has the greatest impact on prevention.
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?