WEEK 2.8

Question 1

before evidence based medicine…

Answer 1

• many medical treatments were either ineffective or harmful
• e.g. blood letting
• however, some older medicines based on evidence

Question 2

standardised evidence based medicine (EBM)

Answer 2

recent movement (1980s and 90s) which emphasizes the importance of unified standards and ranking of evidence across medical practise research

Question 3

what does EBM target?

Answer 3

over reliance on:

• clinical experience and judgment
• background theory

Question 4

EBM recommendations

Answer 4

• update knowledge of medics regularly
• make results of clinical trials more widely known
• fix what constitutes best available evidence (aka evidential weight)

Question 5

randomised controlled trials

Answer 5

• experiment where half of the people are given treat, half given placebo
• without RCT no real medical evidence

Question 6

examples of therapies which do not have RCT evidence but still work

Answer 6

• penicillin for bacterial pneumonia
• diuretics for heart failure
• appendectomy for appendicitis

Question 7

more sophisticated reading of EBM?

Answer 7

• other evidence type may be available and should be consulted
• however, RCT trumps them

Question 8

why are some sources of evidence ranked higher than others?

Answer 8

imposing further contraints on source

Question 9

evidence hierarchy from best to worst

Answer 9

1. meta-analyses and systematic reviews
2. RCTs
3. cohort studies
4. case reports
5. expert opinion

Question 10

how do we make a combined judgment when evidence comes from different sources?

Answer 10

• by assigning weights to evidence
• issue is how to determine weights in non-arbitrary way

Question 11

why choose RCTs?

Answer 11

• in any study, want to ensure that any effect attributed to specific action
• problem = cannot know what would happen to same objects/subjects in absense of action
• overcome problem use a comparison group which isn’t subjected to action

Question 12

1. treatment group
2. control group

Answer 12

1. group subjected to specific action
2. group not subjected to specific action

Question 13

subjects in both treatment and control group must:

Answer 13

1. possess the same conditions under study (e.g. same illness)
2. be differently subjected to actions (e.g. treatment vs non-treatment)

Question 14

issues with RCTs

Answer 14

• individuals in control group may be suffering from more aggressive form
• individuals in control group may be frailer

Question 15

how to mitigate RCT issues?

Answer 15

• remove subjects with confounding factors from study
• equally distribute factors by intential selection

Question 16

what is the major obstacle to make everything equal?

Answer 16

• may be unknown confounding variables (internal validity issues)
• randomisation meant to solve this because unbiased method of distributing subjects into groups (hopefully even distribution of confounding variables but no guarantee)

Question 17

internal validity

Answer 17

when treatment’s impact accurately measured in study population