epidemiological studies (RCT) Flashcards
what is a clinical trial ?
it is a prospective study comparing the effect of an intervention against a placebo or conventional treatment in human beings
what is a single armed clinical trial ?
means that everyone enrolled in the clinical trial will be treated the same way
what is a cross-over design ?
each subject receives all the products in phases , each phase is separated by a wash out period
what are selection of subjects based upon ?
exclusion and inclusion criteria
unlike with case control participants are chosen using eligibility criteria and diagnostic criteria
what are some ethical considerations when selecting subjects for RCT ?
involvement of children
what is the purpose of randomization ?
to ensure that neither investigator nor patient decides the treatment to be assigned
balances the known and the unknown factors
a method to deal with the confounding factors
randomization is the method of choice used to get rid of confounding factors in RCT
what is allocation concealment ?
critical to prevent selection bias , ensures that the patients dont know their allocation
what are the two important methods for removing bias in clinical trials ?
randomization
blinding
what are the levels of blinding ?
individual
investigators
analysts
in what type of studies may blinding of treatment be difficult ?
surgical vs medical treatment
non-pharmacological and behavioural interventions
what is placebo ?
ann inert compound given to subjects in a clinical trial
when is using placebo arms unethical ?
when there is an established intervention
what are the types of RCT endpoints ?
primary endpoints
surrogate endpoints
composite endpoints
safety outcomes
what is a primary endpoint ?
main measurement for a trial
what is a surrogate endpoint ?
biomarker intended for the substitution of a clinical endpoint
reflects how a patient feels
what are composite endpoints ?
where the intervention is considered a success or a failure
what is meant by safety outcomes in RCT ?
rate of adverse events
which documentation should be considered for ethical purposes when wanting to perform a clinical trial ?
helsinki declaration
when should a trial be stopped ?
- if severe or unexpected side effects or complications occur
- if the benefit from the intervention becomes evident and undeniable
how is monitoring of the events in an RCT achieved ?
through interim analyses, sample size must be adjusted for the number of interim analyses
abl ma nelem el wara2 interim analysis is made
which committee is responsible for data throughout the duration of the study ?
data and safety monitoring board ( DSMB)
what is the difference between :
intent to treat analysis
and
per protocol analysis ?
- ITT: involves all participants that are enrolled in the trial regardless if they completed it or not
- per protocol analysis: includes only those who completed the trial
how is efficacy calculated ?
incidence in placebo - incidence in treatment
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incidence in placebo
how do you calculate number needed to treat?
1
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incidence in control - incidence treated
