Lecture 6, part 1 Flashcards
What is a trial? What is the design?
A planned experiment
Designed specifically to evaluate the efficacy of a tx or intervention
What does the investigator do in a trial?
Manipulates the exposure- compare outcomes in a group with intervention to outcomes in a comparable group without intervention
What are common types of trials?
Field
Community
Clinical
More details about field trials
Preventive interventions at the individual levle
Carried out in the field, on people who are not pts (initially dz-free)
Definition of community trials
Preventive intervention applied to groups of ppl
Definition of clinical trials
Therapeutic intervention applied to pts
What do clinical trials do? What is the aim?
Experiment with pts (ppl who already have the dz/outcome) as subjects, generally aimed at preventing various sequelae
What do clinical trials include?
Uncontrolled trials
Non-randomized control trials
Randomized control trials
Why are trials useful?
Evaluate the efficacy of new drugs or other txs for dz
Evaluate new medical/healthcare tech
Evaluate new methods of prevention
Evaluate new programs for screening and dx
Evaluate new methods of providing care
Evaluate new healthcare policies
How trials are designed
The population is divided into eligible and not eligible
The eligible participants are divided into intervention/tx and placebo/usual care groups
Both intervention/tx and placebo/usual care groups are monitored to see whether or not the outcome develops
A trial is essentially a _______ _______ _______ except that the investigator manipulates the exposure.
Prospective cohort study
What should be considered with the placebo group?
Whether use is ethical
If not ethical, compare new tx to standard tx
What outcomes could be measured?
Dz
Recurrence of dz
A precursor to dz
Improved quality of life
All need to be measurable and well-defined before starting the study
Why are comparison groups necessary?
Want to be able to derive a causal interference regarding the relationship between a tx and a subsequent outcome
Without a comparison group, we cannot attribute any improvement (or decline) in condition to the administration of the tx rather than other sources
What is investigated in prevention trials?
Measures that prevent dz occurrence (primary prevention)
What is investigated in therapeutic trials?
A measure that treats an existing condition (secondary prevention)
Purpose of a prevention trial
Removal of a causal factor, addition of an agent, or behavior modification
Purpose of a therapeutic trial
Txs or interventions intended to reduce recurrence, improve survival, or improve quality of life
Among whom is a prevention trial conducted?
The general pop or high-risk individuals
Among whom is a therapeutic trial conducted?
Pts or individuals with the condition of interest
Parallel experimental trial design
Each group receives one tx
Txs are administered concurrently
Crossover experimental trial design
Each group receives all txs one after another
The tx order differs for each group
Washout period may intervene between txs
Simple experimental trial design
Each group gets one tx or intervention
Factorial experimental trial design
Each group gets two or more txs or interventions
Steps in conducting a randomized control trial
Select a sample
Randomize study participants
Measure baseline variables
Apply the intervention
Measure the outcome
Analyze the results