S1L2 Evidence Based Medicine

Question 1

What is evidence based medicine?

Answer 1

The use on conscientious, explicit and judicious use of current best evidence in making decisions about the care of individual patients.

Question 2

What three factors must be considered when using evidence based medicine to select the appropriate treatment?

Answer 2

Clinical expertise
Patient values
Best research evidence

Question 3

What steps are used during a deductive approach?

Answer 3

Identify basic processes
Deduce the best procedure
Apply to the clinical situation.

Question 4

What is the empirical approach?

Answer 4

Scientific methof of inquiry and observation through experiments. Gaining knowledge by observing patients. Testing procedures rather than blindly trusting them.

Question 5

What steps are used during an empirical approach?

Answer 5

Identify the basic processes
Postulate alternative approaches
Test ideas experimentally.

Question 6

What are the different kind of scientific approaches in medicine?

Answer 6

Deductive

Empirical

Question 7

What is lead time bias?

Answer 7

The idea that patients live longer due to early diagnosis, when in reality they just lived longer bowing they had the disease, and died at the same time as they would have with a later diagnosis.

Question 8

How does lead time bias affect screening programmes?

Answer 8

Screening programmes need to b able to prove that earlier diagnosis does actually result in longer life expectancy of patients, with the improvement of their quality of life rather than just having a longer period alive with a bad diagnosis whilst undergoing unpleasant tests and therapies.

Question 9

What types of studies can be conducted in evidence based medicine?

Answer 9

Quantitative (involves numbers)

• observational
• experimental (doing studies)

Qualitative
- discussions/talks/opinions

Question 10

What are the 3 main types of observational study designs?

Answer 10

1. Case reports and case series
2. Cross-sectional studies
3. Correlation studies/ecological

Question 11

What are case reports and case series?

Answer 11

Case reports = one person
Case series = multiple people

Don’t involve a central group, writing facts without drawing conclusions. Helps identify new emerging diseases. Helps suggest aetiology all assocations.

Question 12

How are cross sectional surveys used in evidence based medicine?

Answer 12

Studies prevalence ( Proportion of a given population with disease)
Often used to address questions of time (pattern of disease), place (geographical distribution)and person (personal characteristics)

Question 13

How are Case-control and cohort studies used in evidence based medicine?

Answer 13

Help identify links between possible aetiological agents and disease

Question 14

What are interventional studies?

Answer 14

Experimental studies where participants receive some form of intervention in order to evaluate it.

1) controlled trials - comparing results of 2 different pathway, one used in one hospital, another used in a different hospital

2) RCTs - randomised control trials
Reduce confounding/ bias
Compare 2 treatments
Compare new treatment against placebo/usual care

Question 15

What is a systematic review?

Answer 15

Systematic reviews combines study results together to analyse findings.
Combines:
RCTs
Observational studies 
Qualitative studies.

Question 16

What is the hierarchy of evidence for treatment effectiveness

Answer 16

1) Systematic review of randomised trails
2) Randomised controlled trial
3) Controlled, non-randomised study
4) Observational studies
5) Case series/ case studies
6) consensus / expert views

Question 17

What makes RCTs poor quality?

Answer 17

May have poor randomisation technique
Intervention may be poorly reproducible 
May have biased outcome measurement 
May be analysed poorly 
May not be generalizable.

Question 18

What is PICOS

Answer 18

A way to do a good literature search
P - population or patient group
I - interventions/investigations considered
C - comparator ( control)
O - outcomes considered (not always needed)
S - study design ( may not need this)