Epidemiology/Biostatistics

Question 1

Data is collected from a group of people to assess frequency of disease (and related risk factors) at a particular point in time.

Asks; “What is happening?”

Answer 1

cross-sectional study

observational

disease prevelance

Question 2

Compares a group of people with disease to a group without disease.

Looks for prior exposure or risk factor

Asks, “What happened?”

Odds ratio

Answer 2

Case-control study

observational and retrospective

“Patients with COPD had higher odds of a history of smoking than those without COPD had.”

Question 3

Coompares a group with a given exposure or risk factor to a group without such exposure.

Looks to see if exposure increased the likelihood of disease

Can be prospective (asks, “Who will develope disease?”) or retrospective (“Who developed the disease [exposed vs. nonexposed]?”)

Relative Risk

Answer 3

Cohort study

Observational and prospective or retrospective

“smokers had a higher risk of developing COPD than non-smokers”

Question 4

Measures heritability and influence of environmental factors (“nature vs. nurture”) for monozygotic and dizygotic twins.

Answer 4

Twin concordance study

Compares the frequency with which both monozygotic twins or both dizygotic twins develop same disease.

Question 5

Compares heritability and and influence of environmental factors for siblings raised by biological vs. adoptive parents.

Answer 5

Adoption study

Question 6

Experimental study involving humans. Compares therapeutic benefits of 2 or more treatments, or of treatment and placebo.

Study quality increases with …

Answer 6

Clinical trial

randomization, controlled, and double-blinded

Question 7

Small number of healthy volunteers.

Asks, “Is it safe?”

Answer 7

Phase I Clinical Trial

Assesses safety, toxicity, and pharmacokinetics.

Question 8

Study involving a small number of patients with disease of interest.

Asks, “Does it work?”

Answer 8

Phase II Clinical Trial

Assesses treatment efficacy, optimal dosing, and adverse effects.

Question 9

Study involving a large number of patients randomly assigned either to the treatment under investigation or to the best available treatment (or placebo).

Asks, “Is it as good or better?”

Answer 9

Phase III Clinical Trial

Compares the new treatment to the current standard of care

Question 10

Study involving the postmarketing surveillance trial of patients after approval.

Asks, “Can it stay?”

Answer 10

Phase IV Clinical Trial

Detects rare or long-term adverse effects. Can result in a drug being withdrawn from market.