Question: Which of the following best describes a common bias in observational trials?
Answer Options:
A. Detection bias
B. Recall bias
C. Performance bias
D. Selection bias
Answer: B
Question: A case-control trial examined antibiotic use during pregnancy on childhood cancer. Mothers of control children may have inaccurately recalled antibiotic use. What type of bias is this?
Answer Options:
A. Temporal ambiguity
B. Selection bias
C. Measurement/Detection bias
D. Recall bias
Answer: D
Question: Another case-control trial for antibiotic use in pregnancy with randomly chosen cancer patients vs. random population controls that may not reflect the same exposure distribution. Which bias?
Answer Options:
A. Selection bias
B. Misclassification bias
C. Recall bias
D. Measurement/Detection bias
Answer: A
Question: Refer to Table 2: HR 1.82 (1.23–2.67) for azithromycin vs. amoxicillin days 0–5. Which below is best interpretation?
Answer Options:
A. Patients receiving azithromycin are 1.82 times less likely.
B. Patients receiving amoxicillin are 82% more likely.
C. There is no difference in cardiovascular death risk.
D. Patients receiving azithromycin have 82% higher risk.
Answer: D
Question: Which of the following is not an appropriate composite endpoint for assessing SGLT-2 inhibitors in heart failure?
Answer Options:
A. Cardiovascular deaths
B. All-cause death
C. Non-fatal stroke
D. Urinary tract infections
Answer: D
Question: What are advantages of using a case-control design in the Grijalva et al. study vs. an RCT?
Answer Options:
A. Assigning a benzodiazepine to elderly in RCT might risk falls
B. A case-control can establish definitive causality
C. Allows direct estimation of the vaccination–pneumonia association in real-world
D. Efficient for studying rare outcomes without large samples
E. Results are more generalizable than RCT
Answer: C, D
Question: Based on SHIFT (ivabradine) study baseline characteristics, which patient is the best candidate?
Answer Options:
A. 72 y/o male no CAD, LVEF 38%, HR 65, NYHA II
B. 42 y/o female with CAD, LVEF 25%, HR 85, NYHA III
C. 62 y/o male CAD, LVEF 25%, HR 85, NYHA IV
D. 75 y/o asymptomatic HF, LVEF 32%, HR 75, NYHA II
Answer: B
Question: A weight-loss study recruited 200 motivated gym-goers as the treatment group and the local community as control. Which bias is most apparent?
Answer Options:
(No multiple-choice options were provided in the chat text.)
Answer: Selection bias
Question: An RCT comparing thiazolidinediones vs. placebo on mortality in diabetes: HR (all-cause) = 0.90, HR (CV) = 0.91, HR (HF) = 0.74. Which below best reflects the impact on these endpoints?
Answer Options:
A. Increase CV mortality but decrease all-cause mortality
B. No impact on all-cause or CV mortality
C. Increase CV mortality
D. No impact on any mortality endpoint
Answer: B
Question: Researchers investigated the relationship between postmenopausal hormone therapy and heart disease in women, following 10,000 nurses from 1986 forward. Which design best describes this?
Answer Options:
A. Retrospective cohort study
B. Case-control study
C. Prospective cohort study
D. Randomized controlled trial
Answer: C
Question: Which design is best suited for studying incidence?
Answer Options:
A. Case-control
B. Cohort
C. Cross-sectional
D. Case series
Answer: B
Question: In the article stating “whether influenza vaccines can decrease the risk… remains unclear,” to which STROBE item does this statement best apply?
Answer Options:
A. Study participants (Item 6)
B. Statistical methods (Item 12)
C. Main results (Item 16)
D. Objectives (Item 3)
Answer: D
Question: Researchers investigating a potential association between PFAS exposure and a rare neurological disorder used a case-control design. Why is this most appropriate?
Answer Options:
A. Minimizes recall bias
B. Best method to directly measure disease incidence
C. Easier to establish causality than other designs
D. Ideal for studying rare diseases in the general population
Answer: D