Evidence-based Medicine

Question 1

For prognosis questions, the perfect study is a large

Answer 1

Prospective cohort study

Question 2

For diagnosis questions, the perfect study for “instant” diagnostics is a large

Answer 2

Cross-sectional study

Question 3

For “follow-up” diagnostic questions, the perfect study is a large

Answer 3

Prospective cohort

Question 4

For intervention/exposure questions, the perfect study is a large

Answer 4

RCT

Question 5

How are diagnostic, prognostic study outcomes reported?

Answer 5

Sensitivity, specificity, LR, and ROC statistic

Question 6

We can also use predictive value in certain populations to report the diagnostic/prognostic study outcomes. But this will be

Answer 6

Population-specific

Question 7

Estimate of precision of results

Answer 7

Confidence interval (CI)

Question 8

How are the intervention/exposure study outcomes reported?

Answer 8

ARR, RRR, NNT/H/S, and also P value

Question 9

Probability of finding this level of association when the null hypothesis is true, due completely to CHANCE

Answer 9

P value

Question 10

The conventional cut-off value for statistical significance of P is?

Answer 10

Less than 0.05

Question 11

Provides an estimate of the precision of the results AND statistical significance (how far away is the interval from the null result)

Answer 11

Confidence interval

Question 12

Refers to how well an experiment is done, especially whether it avoids confounding (more than one possible independent variable [cause] acting at the same time)

Answer 12

Internal validity

Question 13

Are your patients and situation similar enough that you think you can apply the results to them? I.e. is there generalizability?

Answer 13

External validity

Question 14

What are three major flaws to an observational study?

Answer 14

Confounding, selection bias, recall bias

Question 15

What are some of the problems we see with RCT’s?

Answer 15

Expensive and time-consuming, randomization/concealment issues, and inadequate blinding/placebo

Question 16

If patients are taking a drug in a trial but have to drop out because of the side effects, we need to perform

Answer 16

Intention-to-treat analysis

Question 17

Good for hypothesis-generating. Generates “translational” research

Answer 17

Bench/animal research

Question 18

Points out rare or new threats, e.g. AIDS, Zika, unknown drug effects

-Hypothesis generating

Answer 18

Case series

Question 19

Snapshot of individuals in a population

–Can directly measure or survey

Answer 19

Cross-sectional study

Question 20

Survey outcomes subject to recall bias, and all are subject to confounding

Answer 20

Cross-sectional study

Question 21

Best for evaluating a test with instant reference, establishing prevalence

-Can look for time trends

Answer 21

Cross-sectional study

Question 22

Snapshot of population inputs and outcomes

Answer 22

Ecological study

Question 23

Best for hypothesis generation and risky exposures

Answer 23

Ecological study

Question 24

Best for - uncommon outcomes (e.g. folate decreasing neural tube defects); and risky exposures

Answer 24

Case control study

Question 25

Good for hypothesis generation and can also be hypothesis-testing

Answer 25

Case-control study

Question 26

One of the major disadvantages of a case-control study is that it is probably most subject to

Answer 26

Confounding/bias

Question 27

Best for – diagnosis or prognosis questions based on information usually captured in routine care; risky or rare exposures; long time-frame issues (e.g. radiation exposure)

Answer 27

Retrospective Cohort study

Question 28

Subject to confounding, missing information, and loss to follow-up

Answer 28

Retrospective cohort study

Question 29

Best for – diagnostic test or prognosis questions; risky or rare exposures -Ex: Framingham heart study

Answer 29

Prospective cohort

Question 30

Expensive/time-consuming and subject to confounding and loss to follow-up

Answer 30

Prospective cohort study

Question 31

Really a type of retrospective cohort, but without any individual records review -Best for – rare outcomes, post-marketing surveillance

Answer 31

"Big Data" studies (Ex: pharmacoepidemiology)

Question 32

Best for – common illnesses; efficacy and common harms of interventions: treatment, screening, prevention, or diagnostic/therapeutic strategy

Answer 32

RCT

Question 33

Disadvantages – therapeutic equipoise limits; expensive/time-consuming; external validity; surrogate or composite outcomes; cross-overs, non-adherence, co-interventions

Answer 33

RCT

Question 34

Best for – questions lacking a good large study, or with multiple high-quality studies

Answer 34

Systematic review