39. THE BASICS OF RANDOMISED CONTROL TRIALS Flashcards
1
Q
- What is the Basic Design of a Randomised Controlled Trial?
A
- A Treatment Group
- A Control (placebo) group
2
Q
- What are the 3 main requirements for a Randomised Controlled Trial?
A
- Conceal
- Randomise
- Blind
3
Q
- What are the 3 main issues with Randomised Controlled Trials?
A
- Loss of Follow-Up
- Non-Compliance
- Contamination
4
Q
- What happens if loss of follow-up, non-compliance and Contamination happen frequently and not at random?
A
- there is major bias in the results
- the power of the study results is decreased
- credibility is lost
5
Q
- What can cause a Loss of follow up?
A
- side effects of the drug
- the participant may move countries
- the patient may die
- the patient may recover
- the patient could get worse
- the patient could lose interest
6
Q
- What does a Loss of Follow-up result in?
A
- Selection bias
7
Q
- What causes Poor Compliance?
A
- side effects of the drug
- negative reactions caused by the treatment
- the patient recovered
- the patient got worse
- the patient lost interest
8
Q
- What does Lack of Compliance result in?
A
- a skewing of the Mean Result
9
Q
- What causes Contamination?
A
- cross overs
- this happens a lot in unblinded control groups
10
Q
- How do we maximise Follow-up and Compliance?
A
- Two screening visits prior to enrolment
- Pre-Randomisation Run-in period
- this makes use of the Placebo or the Active drug - Maintain Blinding
11
Q
- What does this image show?
A
- this is a Randomised Cross Over Design
- we intentionally swap treatment A and B
THE WASHOUT PERIOD:
- the patient does not take any kind of treatment
12
Q
- What are the advantages of this method?
A
- each subject acts as their own control group
- a smaller number of patients is required
- it costs less money
13
Q
- What are the disadvantages of this method?
A
- it is a longer duration than parallel-group studies
- there is a difficulty with the multiple treatment groups
- there is a lot of drop-outs
14
Q
- Define: Non-Randomsied Trials?
A
- the allocation of patients into each treatment group is
not a result of randomisation
15
Q
- Define: Non-Controlled Trials?
A
- clinical trials can take place in a single intervention
group - there is no control group
16
Q
- Why should Non-Randomised Trials and Non-Controlled Trials be avoided?
A
- they have a high likelihood of bias and confounding
17
Q
- What are Quasi-Experimental Designs?
A
- the participants are assigned to a specific treatment
group - there is done using a systematic procedure
- this is not random
EXAMPLE:
- everyone born in February is put in one group
- all males are put in one group
- ect
18
Q
- What are the advantages of Randomised Controlled Trials?
A
- THEY MEASURE THE SAFETY AND EFFICACY
- of an intervention - THEY HAVE A HIGH INTERNAL VALIDITY
- they are able to control selection
- they are able to control confounding
- they are able to control measurement bias - THEY ARE PROSPECTIVE
- THEY ARE AN INCIDENCE STUDY
- THEY LOOK AT CAUSE AND EFFECT
19
Q
- What are the disadvantages of Randomised Controlled Trials?
A
- THEY ARE TIME AND ENERGY INTENSIVE
- especially in Phases I, II and III - THEY ARE EXPENSIVE
- THEY MAY NOT BE ABLE TO BE USED FOR ALL
INTERVENTION SETTINGS - THEY ARE NOT GOOD FOR RARE OUTCOMES
- such as with Cohort Studies - THE ABILITY TO MAKE VALID CONCLUSIONS
- about the internal and external validity
- depends on how well the investigation is designed
- it also depends on how well the investigation is
conducted and reported