Randomised Controlled Trials Flashcards
What are the steps of a randomised controlled trial?
Define, very specifically, the disease of interest, the treatments to be compared, and the outcomes to be measured. Identify eligible patients, invite them to the trial, randomly allocate patients to the new treatment and standard treatment/placebo. Follow up patients identically, minimising loss to follow-up and maximising compliance. Analyse data and obtain results.
What is the definition and purpose of a clinical trial?
Planned experiment (ie. doing something to people, not observing) which involves patients. Designed to elucidate the most appropriate treatment for future patients with a given medical condition.
What must a successful clinical trial provide evidence of?
Efficacy (improve health) and safety (not harmful) of the treatment to a defined group under certain conditions.
In order to provide reliable evidence, what must a clinical trial be?
Fair (unbiased without confounding), controlled comparison, reproducible.
What is the advantage of randomisation?
It removes any confounding, known or unknown.
What is the advantage of double blinding?
Neither the doctor nor the patient know what treatment they’re on. This removes behavioural change in patients and selective biasing doctors.
Why are placebos used?
If no current treatment for the disease exists, placebos are to remove the placebo effect.
What is the disadvantage of comparing to a historical cohort?
Selection is less well defined, it is harder to avoid confounders and potential bias.
What is an explanatory trial?
It only looks at compliant subjects, analysing as-treated to compare the physiological action of the treatments.
What is a pragmatic trial?
Looks at compliant and non-compliant subjects, analysing intention-to-treat which is more useful in routine clinical practice it shows whether patients will take it. Prevents loss of randomisation.
What is a placebo?
An inert substance identical in appearance to the active treatment.
How do you minimise losses to follow up?
Appointments at convenient times, don’t use coercion or inducement, be honest to the patient.
How do you maximise compliance?
Make instruction simple, make treatment is accessible, allow them to ask questions and stay in contact; can be monitored with tests.
What ethics are required for a randomised control trial?
Clinical equipoise, scientifically robust, ethical recruitment, valid consent, voluntariness.
Define clinical equipoise.
Reasonable uncertainty into which drug is better for the patient, not subjecting patients to known less effective or harmful treatment.
