Year 2-Evidence Based Medicine

Question 1

What is evidence-based medicine?

Answer 1

the use of mathematical estimates of the risk of benefit and harm, derived from high-quality research on population samples

Question 2

What is epidemiology?

Answer 2

The study of populations of people

Question 3

What is clinical epidemiology?

Answer 3

The science of applying the principles of population based (epidemiologic) evidence to the management of individual patients

Question 4

What can observational studies show?

Answer 4

Association between one variable and another

Question 5

What can interventions studies used for?

Answer 5

To test a new treatment or intervention

Question 6

What is a cohort study used for?

Answer 6

Looking at causality

Question 7

What is a case control study used for?

Answer 7

Looking at causality

Question 8

What is Cross-sectional/longitudinal studies used for?

Answer 8

Looking at trends.

Question 9

What is bias?

Answer 9

Any trend in the collection, analysis, interpretation, publication or review of data that can lead to conclusions that are systematically different from the truth

Question 10

How do bias and error differ?

Answer 10

Errors occur randomly but bias is a systematic deviation from the truth

Question 11

What is the cofounding factor?

Answer 11

A factor that is associated with both the exposure of interest and the outcome of interest

Question 12

What is Selection Bias?

Answer 12

A sample does not represent population.

Question 13

What is Detection Bias?

Answer 13

Observations in treatment group pursued more than those in control group.

Question 14

What is Observer Bias?

Answer 14

Subjectivity of observer, variance in their decisions.

Question 15

What is Recall Bias?

Answer 15

Patients know which group they are in, and may be more likely to report symptoms.

Question 16

What is Response Bias?

Answer 16

Patients enrolling themselves/self-selecting.

Question 17

What is Publication Bias?

Answer 17

Positive trials more likely to be published.

Question 18

What is incidence?

Answer 18

The number of new cases of a disease in a population, in a given time period, also known as the occurrence rate

Question 19

What does incidence help us to understand?

Answer 19

The risk of the disease

Question 20

What is prevalence?

Answer 20

The total number of cases of a disease in a population, either in a time period or at a specific point in time

Question 21

What does prevalence help us to understand?

Answer 21

The burden of disease

Question 22

What is a cohort study?

Answer 22

A cohort of people are studied based on an exposure and followed up, over time, to evaluate an outcome of interest. Can be prospective or retrospective.

Question 23

What are advantages of a cohort study?

Answer 23

Incidence of disease can be calculated in exposed and non-exposed individuals
It is possible to study multiple outcomes
Bias can be less of an issue than in case-control studies

Question 24

What are disadvantages of a cohort study?

Answer 24

Requires large populations and often a long time to see outcome (expensive), as a result of this – study participants drop out can be a problem.

Question 25

What is the Relative Risk?

Answer 25

It is a measure of the risk of the outcome of interest in the exposed group, relative to the unexposed group.
The outcome measure reported in cohort studies

Question 26

How is the relative risk calculated?

Answer 26

Risk in exposed group ÷ risk in unexposed group = RR

Question 27

What does it mean if the RR is 1?

Answer 27

If the RR is 1, it indicates that there is no difference in effect between the groups.

Question 28

What is a case control study?

Answer 28

A comparison between individuals with a disease of interest and those without the disease of interest. The cases and controls are each assessed to ascertain if they have had exposure to the variable of interest

Question 29

What is a case control study nearly always?

Answer 29

Retrospective

Question 30

What are advantages of case control studies?

Answer 30

Smaller sample sizes generally required
Quicker results
Cheaper

Question 31

What are disadvantages of case control studies?

Answer 31

More prone to bias
Can be difficult to prove causation
Not possible to calculate incidence
Selecting controls can be difficult

Question 32

What is the Odds Ratio?

Answer 32

It is defined as the ratio of the odds of exposure in those with the outcome to those without the outcome

Question 33

How is the Odds Ratio calculated?

Answer 33

Odds of exposure in those with the outcome ÷ odds of exposure in those without the outcome = odds ratio.

Question 34

What does an Odds Ratio of more than 1 mean?

Answer 34

Increased odds of association between exposure and outcome

Question 35

What does an Odds ratio of less than 1 mean?

Answer 35

Decreased odds of association between exposure and outcome

Question 36

What is the purpose of Cross sectional/ longitudinal studies?

Answer 36

Look at outcome and exposure in a population, or an individual, at a specific point in time – they look at a cross section of society.
Helpful in looking at trends in a population

Question 37

What is the gold standard for assessing new treatment/interventions?

Answer 37

The Randomized Controlled Trial (RCT)

Question 38

What is a randomised control trial?

Answer 38

A group of patients are randomized to receive either the new treatment or an alternative – often a placebo though it may be the usual, standard care, or other treatment

Question 39

What is an advantage of a Randomised Control Trail?

Answer 39

Can provide strong evidence for effect with little chance of bias.

Question 40

What are disadvantages of a Randomised Control Trail?

Answer 40

Time consuming
Expensive
Ethical considerations

Question 41

What is a systemic review?

Answer 41

A review of a clearly formulated question that used systematic methods to identify, select and critically appraise relevant research, and to collect and analyse data from the studies that are included in the review.

Question 42

What is a meta-analysis?

Answer 42

The data/statistical part of a systematic review. Pulls together data from individual studies and analyses this. The data is usually presented in a forest plot

Question 43

What is the central vertical line in a Forest Plot?

Answer 43

The line of no effect.

Question 44

What does the solid shape in a Forest Plot represent?

Answer 44

The size of the study.

Question 45

What does the horizontal line in a Forest Plot represent?

Answer 45

The spread of the study

Question 46

What does it mean when the horizontal line crosses the vertical line in forest plot?

Answer 46

The study is not statistically significant.

Question 47

What is a hierarchy of evidence necessary for?

Answer 47

To critically appraise evidence

Question 48

What is causality?

Answer 48

Looking at study results, we may be able to say A is associated, or correlated, with B.
This does not mean that A causes B- Correlation doesn’t equal causation

Question 49

What is quality improvement?

Answer 49

Improving the quality of patient care

Question 50

What type of process is quality improvement?

Answer 50

Systematic process that can drive change

Question 51

What forms part of the QI?

Answer 51

Audit

Question 52

What is an Audit?

Answer 52

Audit is a process – decide on an area, define quality standard, measure performance, change something then re-audit.

Question 53

What is not an audit?

Answer 53

Collecting data and looking at it is not an audit (it’s part of an audit

Question 54

What are the 5 parts of the audit cycle?

Answer 54

Preparing for audit.
 Selecting criteria and standards
 Measure what is happening now.
 Make improvements. 
 Sustain improvement & re-audit.