Evidence Based Medicine

Question 1

What is the purpose of having “Levels of Evidence”

Answer 1

Levels of Evidence (LOE)

1) Ascribe a level of risk of bias in a study design
2) Assist in grading quality of recommendations for guidelines

Question 2

What kind of study is has level 1 LOE?

Answer 2

Systematic reviews and meta-analyses

Question 3

Observational studies

Answer 3

Non-experimental studies that compare 2 or more populations to address a hypothesis about a disease

Question 4

Types of observational studies

Answer 4

In order of increasing strength

• cross-sectional
• case control
• cohort studies

Question 5

Cohort studies

Answer 5

Enrol subjects with EXPOSURE to a risk factor, matched with ‘unexposed’ controls, then follows subjects over time to see if new cases of disease (OUTCOME) develop.

Question 6

Case control studies

Answer 6

Enrol subjects with DISEASE then find out if they have been exposed to RISK FACTORS. Usually retrospective.

Can study multiple risk factors.

Question 7

Cross-sectional studies

Answer 7

Assess EXPOSURE and OUTCOME at the same time.

E.g. in population surveys.

Question 8

P value

Answer 8

c

Question 9

Relative Risk

Answer 9

c

Question 10

Odds Ratio

Answer 10

c

Question 11

Confidence interval

Answer 11

c

Question 12

Mean

Answer 12

c

Question 13

Median

Answer 13

c

Question 14

Mode

Answer 14

c

Question 15

Define a ‘categorical’ variable

Answer 15

c

Question 16

Define a ‘numerical’ variable

Answer 16

c

Question 17

Nominal vs Ordinal variables

Answer 17

c

Question 18

Discrete vs Continuous variables

Answer 18

c

Question 19

Difference of means

Answer 19

c

Question 20

Scatter plot

Answer 20

c

Question 21

Measure of association

Answer 21

c