OCC OCC Evidence-Based Medicine & Research 2

Question 1

Which bias occurs when patients who are lost to follow-up in a study differ systematically from those who complete the study?

Accepted Answer

Attrition bias (loss to follow-up bias)

Answer

Attrition bias occurs when participants who withdraw or are lost differ from those who remain, potentially skewing results.

Question 2

In a cohort study examining smoking and lung cancer, researchers find a hazard ratio (HR) of 3.2. What does this represent?

Accepted Answer

Smokers are 3.2 times more likely to develop lung cancer over time than non-smokers

Answer

A hazard ratio of 3.2 means the exposed group (smokers) have 3.2 times the instantaneous rate of the outcome (lung cancer) compared to the unexposed.

Question 3

A p-value of 0.03 is reported in a clinical trial. What does this indicate?

Accepted Answer

There is a 3% probability that the observed difference occurred by chance if the null hypothesis is true

Answer

A p-value is the probability of observing results as extreme as those found, assuming the null hypothesis (no difference) is true.

Question 4

Which study design is most appropriate for investigating the cause of a rare disease?

Accepted Answer

Case-control study

Answer

Case-control studies are efficient for rare diseases because they start with cases (people who have the disease) and work backward to identify exposures.

Question 5

What is the purpose of an intention-to-treat (ITT) analysis in a randomized controlled trial?

Accepted Answer

Analyze all randomized participants in their originally assigned groups regardless of protocol adherence

Answer

ITT analysis preserves randomization and prevents overestimation of efficacy by including all participants in their originally assigned groups.

OCC - Osteopathic Continuous Certification Practice Test

OCC - Osteopathic Continuous Certification Practice Test

OCC OCC Evidence-Based Medicine & Research 2