1. Clinical Trials Flashcards
What is the definition of a clinical trial?
Any form of planned experiment which involves patients and is designed to elucidate the most appropriate method of treatment for future patients with a given medical condition
What are primary outcomes?
Preferably only one primary outcome
Used in sample size calculation
Most important outcome of trial
What is a secondary outcome?
Other outcomes of interest
Often includes occurrence of side effects
What are the most important ethical considerations for any trial to go ahead?
Trials of new drugs may do harm
So, you should only conduct a trial if you are genuinely in clinical equipoise and don’t know what is best treatment for patients
Patients/participants must understand what participation involves
What does a clinical trial need to be in order to give a fair comparison of effect and safety?
Reproducible - in experimental conditions
Controlled - comparison of interventions
Fair - unbiased without confounding
What are the disadvantages of non-randomised clinical trials?
Allocation bias - by patient, clinician or investigator
Confounding - known and unknown
What do non-randomised clinical trials involve?
The allocation of patients receiving a new treatment to compare with a group of patients receiving the standard treatment
What do comparison with historical controls trials involve?
Comparison of a group of patients who had the standard treatment with a group of patients receiving the new treatment
What are the disadvantages of comparison with historical controls trials?
Selection often less well defined, less rigorous
Treated differently from new treatment group
There may be less information about potential bias/confounders
Unable to control for confounders
What are the benefits of blinding?
Remove allocation bias - by ensuring that randomisation gives each participant an equal chance of being allocated to each of the treatments in the trial
What is a confounder?
A confounder is a factor associated with the exposure and s independently a risk factor for the disease
What is a placebo?
An inert substance made to appear identical in every way to the active formulation with which it is to be compared
How can you minimise losses to follow-up?
Make the follow-up practical and minimise inconvenience
Be honest about the commitment require from participants
Avoid coercion or inducements
Maintain contact with participants
What are the steps involved that need to be considered in a randomised clinical trial?
Disease of interest Treatments to be compared Patients eligible for the trial Outcomes to be measured Possible bias and confounders
