Critical appraisal

Question 1

what are some examples of observational trials?

Answer 1

Interrupted Time Series
Non-randomised cohort
Before and after with controls
Before and after with no controls
After with no before or controls!

Question 2

what are the features of non-randomised cohort trials?

Answer 2

Main design before-and-after
Improvement to add controls
But unknown confounding always a problem
Difficult to determine CAUSALITY

Question 3

what is the gold standard method to assess efficacy of treatment?

Answer 3

randomised control trials

Question 4

what kind of trial is required by regulatory authorities like the FDA?

Answer 4

randomised control trials

Question 5

what are the benefits to RTC?

Answer 5

Random allocation to intervention or control gives likely balance of all factors affecting outcome
Facilitates blind objective unbiased assessment of outcome
Hence any difference in outcome ‘caused’ by the intervention

Question 6

why is trial design important?

Answer 6

incorrect design leads to waste of resources
poor design is unethical if patient is exposed to danger for little return

Question 7

what are the different randomised trial designs?

Answer 7

Parallel group RCTs
Factorial design
Crossover
Cluster randomisation
Stepped-wedge