Understanding Clinical trials

Question 1

what is a clinical trial?

Answer 1

a type of clinical research that compares one treatment or intervention with another

Question 2

what is selection bias and how do you minimise this?

Answer 2

• how participants reveive intervention/control

Minimise through:
- randomisation
- allocation concealment

Question 3

what is performance bias and how can it be minimised?

Answer 3

• 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

Question 4

what is detection bias and how can it be minimised?

Answer 4

• How outcomes are assessed

minimised through:
- objective outcome measures
- blinded outcome measures

Question 5

what is Attrition bias and how is it minimised?

Answer 5

• number of participants dropping out, non-random withdrawal

minimise through:
- “intention to treat prinicple” analysis (any exclusion should be carefully justified)

Question 6

what is reporting bias?

Answer 6

• which outcomes are reported

minimise through:
- registration of trials

Question 7

what 3 things does registration of trials allow for?

Answer 7

• 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

Question 8

what are 5 different types of randomised trial design?

Answer 8

• parallel group
• crossover
  -factorial
• cluster
• platform trials

Question 9

what is a parallel group randomised trial design

Answer 9

• groups receive different interventions in the same time period
• all participants have the same outcomes assessed
• the groups are them compared

Question 10

what are the 3 pros of parallel group trials

Answer 10

• simple
• robust
• both groups treated in the same time period

Question 11

what are the 2 cons of parallel group trials

Answer 11

• only provides differences between groups
• large studies required to study rare events

Question 12

what are crossover trials?

Answer 12

• 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

Question 13

what are the 3 pros of crossover trials?

Answer 13

• 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

Question 14

what are the 5 cons of crossover trials?

Answer 14

• 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

Question 15

what is factorial design?

Answer 15

• 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

Question 16

what are 2 pros of factorial trials

Answer 16

• two trials tested in one
• can potentially determine if treatments work better together (i.e if there is an interaction)

Question 17

what are 2 cons of factorial trials?

Answer 17

• more complicated
• bigger samples sizes might be required depending on the strength of interaction

Question 18

what are cluster randomised trials?

Answer 18

• groups of participants are randomised to a treatment/intervention (e.g. at GP surgeries, communities, hospitals)

Question 19

what are 3 pros of cluster trials

Answer 19

• 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

Question 20

what are 3 cons of cluster trials

Answer 20

• may need many participants
• can be less efficient than individually randomised designs
• may be more complex to set up

Question 21

what are platform trials?

Answer 21

• a master protocol which covers multiple research questions

Question 22

what are 3 advantages of platform trials?

Answer 22

• efficient way to answer multiple research questions quickly
• useful when there are many untested interventions
• potential to greatly shorten time to patient benefit

Question 23

what are 2 disadvantages of platform trials

Answer 23

• complex and expensive to set up and manage
• not necessarily always more efficient than an individual parallel group trial

Question 24

what is superiority in a trial design

Answer 24

• trial is designed to show that a new treatment is better than the control

Question 25

what is Non-inferiority in trial designs?

Answer 25

trial is designed to show that new treatment is not worse than the control

Question 26

what is an explanatory trial?

Answer 26

trials that demonstrate whether an intervention could work in ideal circumstances

Question 27

what is a pragmatic trial

Answer 27

trials where the design mimics routine clinical practice as close as possible, however patients are randomly allocated to treatment