Understanding Clinical trials Flashcards
what is a clinical trial?
a type of clinical research that compares one treatment or intervention with another
what is selection bias and how do you minimise this?
- how participants reveive intervention/control
Minimise through:
- randomisation
- allocation concealment
what is performance bias and how can it be minimised?
- how participants are cared for and co-interventions for the participants
minimise through:
- blinding of participants, team and assessors (withholding knowledge of treatment AFTER assignment
what is detection bias and how can it be minimised?
- How outcomes are assessed
minimised through:
- objective outcome measures
- blinded outcome measures
what is Attrition bias and how is it minimised?
- number of participants dropping out, non-random withdrawal
minimise through:
- “intention to treat prinicple” analysis (any exclusion should be carefully justified)
what is reporting bias?
- which outcomes are reported
minimise through:
- registration of trials
what 3 things does registration of trials allow for?
- ensures all healthcare decisions are informed by all available evidence
- provides opportunity for collaboration and reduces duplication of research efforts
- improves awareness of trials for clinicians, researchers, patients and public
what are 5 different types of randomised trial design?
- parallel group
- crossover
-factorial - cluster
- platform trials
what is a parallel group randomised trial design
- groups receive different interventions in the same time period
- all participants have the same outcomes assessed
- the groups are them compared
what are the 3 pros of parallel group trials
- simple
- robust
- both groups treated in the same time period
what are the 2 cons of parallel group trials
- only provides differences between groups
- large studies required to study rare events
what are crossover trials?
- participant receives ALL treatments
- randomised to an ORDER of treatment
- this allows for comparison of the responses for each subject AND comparison of the responses between the two groups
- must include a washout period
what are the 3 pros of crossover trials?
- smaller number of patients required
- each participant receives both treatments
- can look at responses within each patient with each patient acting as their own control
what are the 5 cons of crossover trials?
- not suitable in certain disease areas
- takes longer
- potential for effect of first treatment to carry over to next
- potential for a ‘period’/time effect
- greater risk of drop out from participants
what is factorial design?
- a type of multi-arm design where participants can receive one or a combination of treatments ( e.g. two separate treatments and a combination of treatments are tested together )
- patients receive none, one or both of the treatments
what are 2 pros of factorial trials
- two trials tested in one
- can potentially determine if treatments work better together (i.e if there is an interaction)
what are 2 cons of factorial trials?
- more complicated
- bigger samples sizes might be required depending on the strength of interaction
what are cluster randomised trials?
- groups of participants are randomised to a treatment/intervention (e.g. at GP surgeries, communities, hospitals)
what are 3 pros of cluster trials
- prevents contamination between indiviudals assigned to different treatments
- useful when individual randomisation is impossible
- may be easier to recruit participants if consent is only for follow-up
what are 3 cons of cluster trials
- may need many participants
- can be less efficient than individually randomised designs
- may be more complex to set up
what are platform trials?
- a master protocol which covers multiple research questions
what are 3 advantages of platform trials?
- efficient way to answer multiple research questions quickly
- useful when there are many untested interventions
- potential to greatly shorten time to patient benefit
what are 2 disadvantages of platform trials
- complex and expensive to set up and manage
- not necessarily always more efficient than an individual parallel group trial
what is superiority in a trial design
- trial is designed to show that a new treatment is better than the control
