Why We Need Randomised Controlled Trials Flashcards
Define “clinical trial”
An experiment involving patients designed to determine the most appropriate treatment of future patients with a medical condition
What are the phases of a clinical trial?
Phase I
Phase II
Phase III
Phase IV
Describe what happens in Phase I clinical trials
Determining clinical pharmacology and toxicity
Describe what happens in Phase II clinical trials
Initial investigation efficacy
Describe what happens in Phase III clinical trials
Full scale evaluation (RCTs)
Describe what happens in Phase IV clinical trials
Post marketing surveillance
What is an RCT? What are the two groups patients are on
An experiment where participants are randomly allocated into groups:
The intervention group
The control group
Why is it important to randomise patients? State 4 reasons
Avoids selection bias
Controls for temporal effects
Controls for regression to the mean
Basis for statistical inference
One way of randomising patients is “Alternation”. What is Alternation and why is it not a good method to randomise
The allocated treatment is alternated in the same patient
This pattern however is predictable and can lead to subversion and bias
One way of randomising patients is using “Quasi-randomisation”. What is this?
Participants are allocated to groups based on month of birth or surname / forename letter
State two issues with using RCTs
Temporal change: People get better or worse irrespective of the condition
Regression to the mean: People with extreme symptoms in the first measurement may regress to the mean following a second measurement
State the names / dates of two RCTs
1954 Salk Polio Vaccine
1984 CAST Trial
What are the alternatives to RCTs?
Case series
Before / After designs
Historical Controls
Non-randomised / Concurrent control trials
Give three examples of bias
Selection Bias
Ascertainment Bias
Performance Bias
Define “clinical equipoise”
A genuine uncertainty in the expert medical community over whether a treatment will be beneficial
