Lecture 16 9/23/24 Flashcards
What are the characteristics of randomized controlled trials?
-gold standard for evaluating efficacy of therapeutic and preventive interventions
-all participants have the same chance of being assigned to each of the study groups
What should be considered before a clinic becomes a trial participant site?
-formally stated protocol
-protocol freely provided to enrollees upon request
-appropriate review of the study
-enrollment expectations and time commitments for enrollees and clinicians
What needs to be included in the protocol for a clinical trial?
-rationale/background
-specific objectives
-statement of design
-inclusion/exclusion criteria
-outline of treatment procedure
-definition of clinical and lab. methods
-methods
-major and minor endpoints
-provisions for observing/recording side effects
-procedures for handling problems
-procedure for informed consent
-sample size calculations and plan for analyzing results
-forms and support letters
Which steps should occur prior to study enrollment?
-study design and funding
-protocol and forms creation
-clearance process
What are the challenges that complicate study enrollment?
-researcher availability at enrollment site
-willingness of potential participant to be contacted
-additional time required to discuss and consent
-combination of clinical knowledge and interpersonal skills
What must be included on the owner consent form?
-purpose of study
-expected duration of participation
-possible discomforts/risks
-treatment and potential benefits
-alternative treatment
-financial obligations
-disclosure of results
-right to withdraw
-termination of participation by investigator
-written consent
What is the most important aspect of owner’s consent?
owners understanding the risk and benefits
What are the important features of randomized clinical trials?
-randomization
-blinding
What are the characteristics of randomization?
-ensures that groups in clinical trials are comparable
-reduces risk of selection bias
-most powerful method of eliminating known and unknown confounding variables
What is the benefit of stratified randomization?
ensures balanced groups that are both equal in size and with regard to potential confounders
What is parallel-group study design?
participants are randomly assigned to groups; all participants in the group receive or do not receive intervention
What is crossover study design?
participants receive or do not receive intervention in a random sequence over time
What is cluster study design?
pre-existing participant groups randomly selected to receive or not receive intervention
What is factorial study design?
participants randomly assigned to group that receives a particular combination of interventions or non-interventions
What are the characteristics of an explanatory outcome RCT?
-tests efficacy of an intervention in research setting
-rigorously selected participants
-highly controlled conditions
What are the characteristics of a pragmatic outcome RCT?
-tests effectiveness of intervention in everyday practice
-relatively unselected participants
-flexible conditions
What is a superiority trial?
one intervention is hypothesized to be superior to another in a statistically significant way
What is a non-inferiority trial?
determine whether a new treatment is no worse than a reference treatment
What is an equivalence trial?
tests hypothesis that two interventions are indistinguishable
What are the comparison group types?
-no intervention
-observation
-placebo treatment
-standard treatment
What are the characteristics of the no-intervention group?
-control group receives no intervention whatsoever
-can have a historically controlled study when comparing intervention groups with a similar group from the past who received no interventions
What are the characteristics of the observation group?
-control group does not receive any intervention AND is carefully monitored
-helps account for Hawthorne effect
What is the Hawthorne effect?
observed effect attributable to being included in a scientific study; knowledge of study participation influences behavior
What are the characteristics of the placebo treatment group?
-placebo is an inactive substance given as a comparison to the treatment under study
-unethical to withhold treatment via use of placebo for life-threatening/serious illness; must give routine treatment and compare to novel treatment
What is the placebo effect?
observed effect that is usually beneficial and attributable to the expectation that the regimen will have an effect
What are the characteristics of the standard treatment group?
group that receives current market leader or the drug that has been available the longest
What is blinding?
individuals involved in the study are kept unaware of the assigned intervention
What are the types of blinding?
-single: patient/owner is blinded
-double: patient/owner and clinician are blinded
-triple: patient/owner, clinician, and data analyst are blinded
What are the benefits of blinding?
-minimize observation bias
-improve patient compliance and retention
-reduce co-interventions
What is intention-to-treat analysis?
-use every subject who was randomized according to treatment assignment
-ignore non-compliance, protocol deviations, withdrawal, and anything that happens after randomization
Why is intention-to-treat analysis used?
-analysis based on compliant participants only can lead to a skewed positive response rate due to systematic bias and confounding effect
-ITT analysis reduces likelihood of systematic error
What is a primary study?
study where the investigators enroll the study participants themselves and/or follow them throughout the study
What is a secondary study?
study that synthesizes several primary studies with a goal of addressing a unique hypothesis
What is a systematic review?
answers a defined research question by collecting and summarizing all empirical evidence from primary studies that fits pre-specified eligibility criteria
What is a meta-analysis?
use of statistical methods to summarize the results of systematic reviews
