RCT

Question 1

How do you analyse a paper on TREATMENT using the RABITFuR mnemonic

Answer 1

Randomisation
Allocation concealment
Blinding
Intention to treat analysis
Treatment Effect
Follow up Rate
Results

Question 2

What are the types of randomisation

Answer 2

Simple randomisation
Block Randomisation
Stratified Block randomisation

Question 3

What is randomisation

Answer 3

The allocation of participants to groups by chance to ensure that both groups have equal known and unknown prognostic factors (1 mark) so that the results from the trial is attributed to the intervention alone (1 mark)

Question 4

What is allocation concealment

Answer 4

The process of ensuring that the person who is making the decision about enrolling a patient is unaware of whether the next patient enrolled will be entered into the intervention or control group (1 mark) to prevent selection bias (1 mark)

Question 5

What is blinding

Answer 5

The process of ensuring that the personnel (patients, care giver or outcome assessor) are unaware of which patients have been assigned to the intervention or control group

Question 6

What is the difference between blinding and allocation concealment

Answer 6

1. Allocation concealment can always be achieved, whereas blinding may not in some instances
2. Allocation concealment occurs before and up to the point of allocation, whereas blinding occurs after allocation
3. Allocation concealment prevents selection bias, whereas blinding prevents performance or measurement bias

Question 7

What is intention to treat analysis

Answer 7

Patients are analysed based on the group they are randomised to irrespective of what treatment they receive

Question 8

Why is Allocation concealment important

Answer 8

1. Protects the integrity of the randomization process, protects the assignment sequence before and until treatment allocation to
   facilitate blinding downstream
2. Minimizes effect of selection bias. Whereby knowledge of the next treatment allocation might influence clinicians’ decision to include/exclude patient or Influence patient’s decision to withhold consent or to participate in the trial
3. Uphold principle of justice – all patients have equal chance of receiving either intervention or control

Question 9

Why is intention to treat analysis important

Answer 9

1. In reality, patients adherence to treatment is an important marker or the failure or success of a treatment. Excluding such patients would be omitting important information about the performance of the treatment
2. Removal of patients post randomisation, from analysis disturbs the prognostic balance achieved during the randomisation process

Question 10

What is an adjusted analysis

Answer 10

A statistical analytical tools (eg regression) used to take into account differences in baseline characteristics and prognostic factors between groups that may influence outcomes

Question 11

What is 95% confidence interval in lay man terms

Answer 11

There is 95% certainty that the point estimate lies between the ranges of the confidence interval

Question 12

What is the purpose of an inclusion criteria

Answer 12

Identifies the population of interest and focusses the research study on this population of interest

Question 13

What is the purpose of an exclusion criteria

Answer 13

1. Removes populations that have a confounder that affects the outcome of interest
2. Remove vulnerable populations who are high risk of a negative outcome
3. Limit the size of the study population

Question 14

What is an open label trial?

Answer 14

1. A trial where participants and care givers are not blinded. This is often due to practical or ethical reasons. It is open to performance bias

Question 15

How do you limit the reduction in internal validity from an open label trial

Answer 15

1. Have outcome assessors that are blinded
2. Have objective outcomes

Question 16

What is the importance of blinding
1. Patients
2. Caregivers
3. Outcome Assessors

Answer 16

1. Prevent placebo effect
   2a) Prevents differential administration of therapy that affect the outcome of interest
2. Prevents bias in decision about whether or not a patient has the outcome of interest (detection bias)

Question 17

What is selection bias and how to we prevent it in a randomised controlled trial

Answer 17

Selection bias refers to a difference in the baseline characteristics of the groups that are compared
It can be prevented with proper randomisation and allocation concealment

Question 18

How does a confounder and a bias differ

Answer 18

1. In the presence of a confounder, measure results are true, but the conclusion is flawed as the effect of exposure on outcome is mixed with the confounder. In the presence of a bias, the measures results are incorrect due to a systematic error that skews the results from the truth.
2. A confounder, if known, can be adjusted for pre or post hoc. A bias, once detected cannot be adjusted for .

Question 19

What is a confounder

Answer 19

A confounder is a factor that influences the exposure and the outcome but does not exist in the casual relationship between exposure and outcome