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Flashcards in WEEK 2.8 Deck (17)
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1
Q

before evidence based medicine…

A
  • many medical treatments were either ineffective or harmful
  • e.g. blood letting
  • however, some older medicines based on evidence
2
Q

standardised evidence based medicine (EBM)

A

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

3
Q

what does EBM target?

A

over reliance on:

  • clinical experience and judgment
  • background theory
4
Q

EBM recommendations

A
  • update knowledge of medics regularly
  • make results of clinical trials more widely known
  • fix what constitutes best available evidence (aka evidential weight)
5
Q

randomised controlled trials

A
  • experiment where half of the people are given treat, half given placebo
  • without RCT no real medical evidence
6
Q

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

A
  • penicillin for bacterial pneumonia
  • diuretics for heart failure
  • appendectomy for appendicitis
7
Q

more sophisticated reading of EBM?

A
  • other evidence type may be available and should be consulted
  • however, RCT trumps them
8
Q

why are some sources of evidence ranked higher than others?

A

imposing further contraints on source

9
Q

evidence hierarchy from best to worst

A
  1. meta-analyses and systematic reviews
  2. RCTs
  3. cohort studies
  4. case reports
  5. expert opinion
10
Q

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

A
  • by assigning weights to evidence
  • issue is how to determine weights in non-arbitrary way
11
Q

why choose RCTs?

A
  • 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
12
Q
  1. treatment group
  2. control group
A
  1. group subjected to specific action
  2. group not subjected to specific action
13
Q

subjects in both treatment and control group must:

A
  1. possess the same conditions under study (e.g. same illness)
  2. be differently subjected to actions (e.g. treatment vs non-treatment)
14
Q

issues with RCTs

A
  • individuals in control group may be suffering from more aggressive form
  • individuals in control group may be frailer
15
Q

how to mitigate RCT issues?

A
  • remove subjects with confounding factors from study
  • equally distribute factors by intential selection
16
Q

what is the major obstacle to make everything equal?

A
  • 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)
17
Q

internal validity

A

when treatment’s impact accurately measured in study population