Randomised Controlled Trials

Question 1

Outline the basis of a RCT

Answer 1

Patients are randomly assigned either a new drug or the standard treatment. They are followed up over time to see the outcomes.

Question 2

What is efficacy with regard to RCT?

Answer 2

The ability of a heath care intervention to improve the health of a designed group under specific conditions.

Question 3

List the 5 stages of drug development

Answer 3

Laboratory studies
Volunteer studies
Treatment studies
Clinical trials
Post marketing surveillance

Question 4

Describe a problem with non-randomised control trials

Answer 4

Allocation bias may occur. Confounding factors will be present

Question 5

Describe a problem with comparing a new drug to a ‘historical’ control group

Answer 5

The standard treatment group often have a less vigorous selection process. They will have been treated differently. There will be less information about bias and confounding factors.

Question 6

What is a:

i. ) single blind test?
ii. ) double blind test?

Answer 6

i. ) One of the patient, clinician or assessor does not know the treatment allocation
ii. ) Two of the patient, clinician or assessor does not know the treatment allocation

Question 7

Why is blind testing important?

Answer 7

The patient, clinician or assessor may alter their behaviour or expectation of the outcome depending on how the patient is treated.

Question 8

What is the placebo effect?

Answer 8

The patient’s attitude and illness improves because they are being treated even if the therapy is having no therapeutic effect.

Question 9

How is the placebo effect overcome in RCT?

Answer 9

A placebo drug is used. It is inert but made to look exactly like the drug being tested.

Question 10

Why is it important to inform a patient they may receive a placebo in a RCT?

Answer 10

It may be seen as ‘deception’

Question 11

List and give an example of the 3 types of outcome for a RCT

Answer 11

Patho-physiological: tumour size
Clinically defined: death, disease
Patient-focussed: quality of life

Question 12

Give 2 ways that follow-up losses can be reduced

Answer 12

Follow-up should be practical and convenient
Patients need to be told of commitment before they join
Coercion should be avoided

Question 13

Give 3 reasons why a patient may not comply with treatment

Answer 13

Misunderstand instructions
Don't like treatment
Think its not working
Prefer to take another treatment
Can't be bothered to take treatment

Question 14

Define ‘as-treated’ analysis

Answer 14

Analyse only those who completed follow-up and complied with treatment. This compares the physiological effects of the treatments

Question 15

Describe a problem with ‘as-treated’ analysis

Answer 15

The effects of randomisation are lost as non-compliers are likely to be systematically different from compliers

Question 16

Define ‘intention to treat’ analysis

Answer 16

Analyse according to the original allocation to treatment groups regardless of follow-ups or compliance. It compares the likely effects of using the treatment in routine practice

Question 17

What is a ‘clinical trial’?

Answer 17

Any form of planned experiment which involves patients and is designed to elucidate the most appropriate method of treatment of future patients with a given medical condition

Question 18

List the 4 principles of Individual Ethics

Answer 18

The Principle of Beneficence (do good)
The Principle of Non-maleficence (do not harm)
The Principle of Autonomy (right to decide own future)
The Principle of Justice (no favourites)

Question 19

What is ‘clinical equipoise’?

Answer 19

Reasonable uncertainty or general ignorance about the better treatment or intervention

Question 20

State in what ways a RCT must be scientifically robust?

Answer 20

It must address a relevant or important issue and ask a valid question.
It must be able to reach a sound conclusion and have an appropriate study design and protocol.
It must justify the use of a placebo
The risk of harm must be acceptable compared to the anticipated benefits.

Question 21

Give an example of a group of people that may be inappropriately excluded from a study

Answer 21

People who it is difficult to get valid consent from (children, mentally ill, immigrants)

Question 22

Give an example of a group of people who may be inappropriately included in a study

Answer 22

Participants from communities that will not benefit from the study, high risk of harm (pregnant women), language barrier

Question 23

List 4 conditions of obtaining valid consent

Answer 23

Patient must be informed by a knowledgable informant
The information must be given in a written and verbal form
There must be a cooling off period
There must always be freedom to opt out

Question 24

What is ‘voluntariness’?

Answer 24

The patient must not be coerced, manipulated or influenced into joining a study