Randomised Trials and Other Evidence Flashcards Preview

Year 3: CSP & PH > Randomised Trials and Other Evidence > Flashcards

Flashcards in Randomised Trials and Other Evidence Deck (10)
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1
Q

What are ‘parallel groups’ when used in randomised trials?

A

when the effect of a treatment is curative (non-reversible)

2
Q

What are ‘cross-over groups’ when used in randomised trials?

A

when the treatment effect is reversible

3
Q

What are the advantages of cross-over trials vs parallel groups trials?

A
  • Fewer participants needed
  • Allows qualitative data to be sued to avoid ‘scores’ or quantifying subjective symptoms
  • Compares 2 drugs in the same individual rather than one drug in two different people
  • Can omit non-compliers in the analysis as the participant is their own control
4
Q

What is an interventional study design?

A

parallel or cross-over randomised trial

5
Q

What is an observational study design?

A

cohort (prospective) or case control (retrospective study)

6
Q

What are the pros and cons of cohort studies?

A
  • Rigorous
  • Long duration
  • Large size required
  • Susceptible to confounders
7
Q

What are the pros and cons of case-control studies?

A
  • Quick
  • Small numbers needed
  • Susceptible to bias – especially recall bias
  • Susceptible to confounders
8
Q

What is an odds ratio?

A

The odds of an event to the odds of the non-event

9
Q

What is ‘relative risk’?

A

The risk of an event happening against the whole group

10
Q

What’s the difference between an odds ratio and a relative risk?

A
  • Odds ratio – the odds of an event to the odds of the non-event
  • Relative risk – the risk of an event happening against the whole group