RCT Flashcards

1
Q

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

A

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

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2
Q

What are the types of randomisation

A

Simple randomisation
Block Randomisation
Stratified Block randomisation

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3
Q

What is randomisation

A

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)

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4
Q

What is allocation concealment

A

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)

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5
Q

What is blinding

A

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

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6
Q

What is the difference between blinding and allocation concealment

A
  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
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7
Q

What is intention to treat analysis

A

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

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8
Q

Why is Allocation concealment important

A
  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
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9
Q

Why is intention to treat analysis important

A
  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
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10
Q

What is an adjusted analysis

A

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

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11
Q

What is 95% confidence interval in lay man terms

A

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

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12
Q

What is the purpose of an inclusion criteria

A

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

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13
Q

What is the purpose of an exclusion criteria

A
  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
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14
Q

What is an open label trial?

A
  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
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15
Q

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

A
  1. Have outcome assessors that are blinded
  2. Have objective outcomes
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16
Q

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

A
  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)
17
Q

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

A

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

18
Q

How does a confounder and a bias differ

A
  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 .
19
Q

What is a confounder

A

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

20
Q
A