Chapter 14 Flashcards
What are the types of clinical trials?
Therapeutic trials: effect of an intervention
Diagnostic trials: accuracy of diagnostic procedures
Preventive trials: evaluation of whether a procedure reduces the risk of developing a disease or disorder
What are randomized control trials?
Gold standard for experimental research
Random assignment
Two or more groups
- Experimental group
- Control group
Measurements
- Pre-intervention
- Post-intervention
What is an independent variable?
the intervention
Active variable: manipulated by researcher and assigned
Attribute variable: individual characteristic, such as age or gender
What is a dependent variable?
outcome response
What is random assignment?
Process of assigning subjects to groups
- Participants have an equal chance of being assigned to any group
Minimizes bias by creating groups that are similar at the start of the trial
Random assignment is different than random selection
What are random assignment strategies?
Simple random assignment
Block random assignment
Stratified random assignment
Cluster random assignment
Random consent design
Assignment by patient preference
Run-in period
What is concealed allocation?
Ensures group assignment is done without knowledge of those involved in the experimental process
Minimizes bias in group formation
Examples:
* Sealed envelopes
* External service separate from the research
institution
What are types of control groups?
Inactive controls
* Placebo
* Sham
* Attention control group
Wait list controls
Active controls
What is blinding?
Minimizes observation bias by ensuring those
involved in the study are unaware of a
subject’s group assignment
* Participants
* Care givers
* Outcome assessors
Also referred to as masking
“Double blind” means both participants and
researchers are unaware of group assignment
What are open-label trials?
No blinding of researchers or participants due to logistic or ethical reasons
Potential biases
* Detection bias
* Performance bias
What are explanatory trials?
RCT
Ideal situations to control for confounding
‒ Strict and broad exclusion criteria
‒ Standardized treatment protocol
What are pragmatic trials?
PCT
More reflective of practice situations
‒ Diverse patient populations with fewer exclusion criteria
‒ Active controls
‒ Treatment reflects practice and is less standardized
What are the phases of clinical trials?
Preclinical phase
Phase I
* Is the treatment safe?
Phase II
* Does the treatment work?
Phase III
* How does this treatment compare with standard care?
Phase IV
* What else do we need to know?
What are superiority trials?
Newer intervention better than usual care
What are non-inferiority trials?
Newer intervention is “not worse” than usual care,
can be an acceptable substitute
Must specify “non-inferiority margin” – how much
difference between new and usual care would
indicate “no worse” outcome
