Analytical Interventional Studies The purpose of an analytic study in epidemiology is to identify and quantify the relationship between an exposure and a health outcome Analytical Interventional Studies ID: 911850
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Slide1
Study Design
Analytical Interventional Studies
Slide2Analytical Interventional Studies
The purpose of an analytic study in epidemiology is to identify and quantify the relationship between an exposure and a health outcome.
Slide3Analytical Interventional Studies
Interventional studies are those in which the research subjects are assigned by the investigator to
a treatment or other intervention
, and their outcomes are measured.
Observational studies are those in which
individuals are observed
and their outcomes are measured by the investigators.
Slide4Analytical Interventional Studies
There are two major types of intervention studies:
Controlled clinical trials in which individual subjects are assigned to one or another of the competing interventions, or
Community interventions, in which an intervention is assigned to an entire group.
Slide5Randomized Controlled Trials
Randomized controlled trials are carefully planned projects that study the effect of a therapy on real patients. They include methodologies that reduce the potential for bias and that allow for comparison between intervention groups and control groups (no intervention).
Slide6Randomized Controlled Trials
Participants are randomly assigned into an experimental group or a
control
group. As the study is conducted, the only expected difference between the
control
and experimental groups in a
randomized controlled trial
(RCT) is the outcome variable being studied.
Slide7Randomized Controlled Trials
From:
Suny
Downstate Medical Center, Evidence Based Medicine Tutorial,
http://
library.downstate.edu/EBM2/2200.htm
Slide8Double Blind Randomized Controlled Trial
A double blind study is one in which neither the patient nor the physician knows whether the patient is receiving the treatment of interest or the control treatment.
Slide9Double Blind Randomized Controlled Trial
From:
Suny
Downstate Medical Center, Evidence Based Medicine Tutorial,
http://
library.downstate.edu/EBM2/2300.htm
Slide10Placebo Controlled Study
Placebo-controlled studies are a way of testing a medical therapy in which, in addition to a group of subjects that receives the treatment to be evaluated, a separate control group receives a sham "placebo" treatment which is specifically designed to have no real effect.
Slide11Placebo Controlled Study
Placebos are most commonly used in blinded trials, where subjects do not know whether they are receiving real or placebo treatment. Often, there is also a further "natural history" group that does not receive any treatment at all.
Slide12Crossover Design
A controlled trial where each study participant has both therapies,
e.g
, is
randomised
to treatment A first, at the crossover point they then start treatment B. Only relevant if the outcome is reversible with time,
e.g
, symptoms. Subjects act as own control.
Slide13Crossover Design
From: The Prehospital Research Support site,
http://prehospitalresearch.eu/?
p=1961
Slide14Superiority/
Noninferiority/Equivalence Trials
In biomedical and mental health research, by far the most common conceptual approach is traditional significance testing in between-group designs, useful for determining if group outcomes are clinically and statistically different from each other and if so, in which direction.
This is the standard approach used in most treatment outcome studies, where it is hypothesized that an experimental treatment is superior to a comparison treatment.
These are superiority trials.
Slide15Superiority/
Noninferiority/Equivalence Trials
“
Noninferiority
” and “equivalence” are often used interchangeably to refer to trials in which the primary objective is to show that a novel intervention is as effective as the standard intervention.
Slide16Superiority/
Noninferiority/Equivalence Trials
Noninferiority
designs are a one-sided test used to determine if a novel intervention is no worse than a standard intervention.
A
noninferiority
trial is designed to show that the novel treatment is no less than a certain amount from the standard intervention (i.e., a one-sided test)
Slide17Superiority/
Noninferiority/Equivalence Trials
Equivalence designs, a two-sided test, pose a similar question, but also allow for the possibility that the novel intervention is no better than the standard one.
An equivalence trial is a trial designed to show that two interventions do not differ in either direction by more than a pre-specified unimportant or insignificant amount (i.e., a two-sided test),
Slide18Superiority/
Noninferiority/Equivalence Trials
EQUIVALENCE vs NON-INFERIORITY vs SUPERIORITY TRIALS:
http://
www.pvanuden.com/2015/04/equivalence-vs-non-inferiority-vs.html
Slide19Community Intervention
In contrast to a controlled clinical trial, a community intervention allocates the trial to a group of subjects. These types of trials are generally conducted when the intervention inherently operates at a group-level (e.g., changing a law or policy) or because it would be difficult to give the intervention to some people in the group while withholding it from others.
Slide20Community Intervention
Group units might be families, schools, or medical practices.
In the 1940s the effectiveness of fluoride in preventing dental caries was tested comparing the frequency of caries in the children in Kingston and Newburgh, New York after Newburgh had had fluoride added to the town's drinking water.
Slide21Question
A control group of pediatric patients with asthma was assigned to be given standard asthma educational resources, while the experimental group of pediatric patients with asthma was assigned to be given standard resources plus multimedia resources. The study found a reduction in daily symptoms, in emergency room visits, in school days missed, and in days of limited activity in the group given multimedia education resources. Which of the following correctly identifies the study design used by the researcher?
Community Intervention
Double Blind Randomized Controlled Trial
Randomized Controlled Trial
Slide22Answer
Randomized Controlled TrialSubjects were randomly assigned to one or another of competing interventions.
Slide23Question
In an ongoing study a researcher hypothesizes that using a
telemental
health modality will not be worse than the traditional mode of service delivery (face-to-face), on both clinical and process measures, for providing Cognitive Processing Therapy in a group format for veterans with PTSD. Which of the following correctly identifies the study design used by the researcher?
Equivalence Trial
Noninferiority
Trial
Superiority Trial
Slide24Answer
Noninferiority Trial
A
noninferiority
trial aims to demonstrate that the test product is not worse than the comparator by more than a small pre-specified amount. This amount is known as the
noninferiority
margin, or delta.