Lecture 6 - RCT Flashcards
What are the 3 reasons to conduct RCT?
evaluate new intervention before its given regulatory approval, evaluate controversial intervention, or to gain regulatory approval
What is the first phase of an RCT
small study of 20-80 healthy volunteers who gets the drug
what is the purpose of phase 1 of an rct
assess toxicity and pharmacological effects
what is the second phase of an rct
study 100-200 diseased person and give them drug
what is the purpose of phase 2 of an rct
assess safety and efficacy
what is the third phase of an rct
RCT which is required for regulatory approval
what is the purpose of phase 3 of an rct
assess effectiveness of new intervention compared to standard/placebo
what is the fourth phase of an rct
follow up rct subjects past official end of RCT
fourth phase of rct is classified as what study
observational study
what is the purpose of phase 4 of an rct
assess rare side effects
What is a single centred rct
patient recruited from same clinic/hospital
what is a multi centred rct
patient recruited from diff clinic/hospital
What are the three contributing factors of ___- that contribute to strength of RCT?
randomization ; 1. each subject has equal chance of being assigned to either group 2. equal # of ppl in each group 3. group subjects based on similar factors except intervention
what is stratified randomization
divide pop into layers (stratum) by variable and randomize within each group
What does stratified randomization do?
increases comparability btw two groups by focusing on one or more prognostic variable; ensures prognostic variables are equally distributed
what is single blind
blind participants to eliminate participant bias
what is double blind
blind data collectors/analysts to eliminate investigator bias
what is triple blind
blind staff that administer treatment
define washout period
time btw end of 1st intervention and start of 2nd must be long enough to wash out any carry over from 1 intervention (IN PLANNED CROSS OVER)
define ordering effect
patients react differently to 1st intervention bc of psychological effects of being studied
define factorial design
test 2 diff drugs on same pop; drugs have diff outcomes and independent modes of action
how many groups are in a factorial design
4
what are the cons of factorial design
might negatively impact compliance and recruitment
what is intent to treat analysis
analyze patients according to original assignment
define internal validity
degree to which a study provides an unbiased estimate of what it claims to measure ; conducted properly
define external validity
results are generalizable
RCTs assess what? therefore they have _____ valditiy
efficacy of intervention; internal validity
what are cons of RCTs
subjects are atypical (good compliers, no comorbid disease)
define clinical equipose
only expert medical community needs to be uncertain
when cant you use an rct
chronic conditions, study rare side effects, randomization is unethical
Observational studies arent ____ but assigned based on ________ wherease RCT participants are assigned based on _______
randomized, observation; randomization
