Clinical trials Flashcards
What is a clinical trial
A study comparing and assessing the effectiveness of 2 or more treatments
What occurs in a phase I clinical trial
Test the safety of the treatment in a small number of healthy volunteers
What occurs in a phase II clinical trial
Testing the efficacy of a treatment + safety in a few hundred people who have the condition
What occurs in a phase III clinical trial
Compare the new treatment with a current one or a placebo to see how well it works + side effects in thousands of patients
What occurs in a phase IV clinical trial
Measure the effect in various populations after the drug has been marketed + rare side effects
What are the key considerations for a clinical trial
Objectives, patient selection, controls, study size, unbiased data collection, specific design, ethics, analysis
Why are controls needed
placebo effect regression to the mean Acclimatisation Seasonal effect Basis of the study question
What is represented by alpha and beta in study size
alpha = significance of observational difference Beta = confidence by which a -ve result is genuine
How is power calculated
1-beta
What are the advantages of randomisation
Validates staistics
Excludes allocation
Equally distributes prognostic factors
Stratification
Why may bias occur in clinical trials
Sponsorship
Patient selection/allocation
Prejudice of patient or observer
Faulty method, analysis, interpretation
What are the pros and cons of blindness
Doctors and patient knowledge bias are removed
Withdrawal bias removed
Impossible
Ethics
Cost
Titration
What must be considered with withdrawn subjects
is it due to treatment failure?
is it due to the condition?
allocation/measurement/reporting bias
What are the ethical considerations taken in a clinical trial
No unnecessary risk Is there a benefit? Placebo effect Committee approval Informed consent Entry criteria Withdrawal criteria Stop the study criteria
What are the advantages of a parallel study
Big numbers
Curative
Long effect seen
