39. THE BASICS OF RANDOMISED CONTROL TRIALS

Question 1

1. What is the Basic Design of a Randomised Controlled Trial?

Answer 1

1. A Treatment Group
2. A Control (placebo) group

Question 2

2. What are the 3 main requirements for a Randomised Controlled Trial?

Answer 2

1. Conceal
2. Randomise
3. Blind

Question 3

3. What are the 3 main issues with Randomised Controlled Trials?

Answer 3

1. Loss of Follow-Up
2. Non-Compliance
3. Contamination

Question 4

4. What happens if loss of follow-up, non-compliance and Contamination happen frequently and not at random?

Answer 4

• there is major bias in the results
• the power of the study results is decreased
• credibility is lost

Question 5

5. What can cause a Loss of follow up?

Answer 5

• 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

Question 6

6. What does a Loss of Follow-up result in?

Answer 6

• Selection bias

Question 7

7. What causes Poor Compliance?

Answer 7

• side effects of the drug
• negative reactions caused by the treatment
• the patient recovered
• the patient got worse
• the patient lost interest

Question 8

8. What does Lack of Compliance result in?

Answer 8

• a skewing of the Mean Result

Question 9

9. What causes Contamination?

Answer 9

• cross overs
• this happens a lot in unblinded control groups

Question 10

10. How do we maximise Follow-up and Compliance?

Answer 10

1. Two screening visits prior to enrolment
2. Pre-Randomisation Run-in period
   - this makes use of the Placebo or the Active drug
3. Maintain Blinding

Question 11

11. What does this image show?

Answer 11

• 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

Question 12

12. What are the advantages of this method?

Answer 12

• each subject acts as their own control group
• a smaller number of patients is required
• it costs less money

Question 13

13. What are the disadvantages of this method?

Answer 13

• 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

Question 14

14. Define: Non-Randomsied Trials?

Answer 14

• the allocation of patients into each treatment group is
  not a result of randomisation

Question 15

15. Define: Non-Controlled Trials?

Answer 15

• clinical trials can take place in a single intervention
  group
• there is no control group

Question 16

16. Why should Non-Randomised Trials and Non-Controlled Trials be avoided?

Answer 16

• they have a high likelihood of bias and confounding

Question 17

17. What are Quasi-Experimental Designs?

Answer 17

• 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

Question 18

18. What are the advantages of Randomised Controlled Trials?

Answer 18

1. THEY MEASURE THE SAFETY AND EFFICACY
   - of an intervention
2. 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
3. THEY ARE PROSPECTIVE
4. THEY ARE AN INCIDENCE STUDY
5. THEY LOOK AT CAUSE AND EFFECT

Question 19

19. What are the disadvantages of Randomised Controlled Trials?

Answer 19

1. THEY ARE TIME AND ENERGY INTENSIVE
   - especially in Phases I, II and III
2. THEY ARE EXPENSIVE
3. THEY MAY NOT BE ABLE TO BE USED FOR ALL
   INTERVENTION SETTINGS
4. THEY ARE NOT GOOD FOR RARE OUTCOMES
   - such as with Cohort Studies
5. 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