Epidemiological studies design: Interventional/clinical/ex perimental Study Designs
Interventional Study Designs •
Use same approach as experimental design • •
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Random assignment to study arms Researcher controls the exposure
Indirect method for learning more about a disease • •
Used to test the effects of removing risk factors or adding protective factors on subsequent disease development Never used to directly test whether an exposure causes a disease
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The goal of intervention studies is to test the efficacy of specific treatments or preventive measures by assigning individual subjects to one of two or more treatment or prevention options ď ľ
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In contrast to case-control studies and cohort studies, that is to test hypotheses about the determinants of disease
often test the efficacy of drugs, but one might also use this design to test the efficacy of differing management strategies or regimens
Example of interventional study
randomized controlled trials (RCTs)
In clinical research, RCTs are the best way to study the safety and efficacy of new treatments
In such trials the participants who receive the treatment under study are assigned at random (by chance, like the flip of a coin).
This is necessary to ensure that the outcomes are determined only by the treatment under study and not by other factors that could otherwise influence treatment assignment.
Other participants who, by the randomization process, serve as controls receive a standard treatment or placebo treatment (a pill or procedure that does not include active ingredients). Treatment group Ethics approval, patients recruitment
Consent patients screening for inclusion criteria, those who failed excluded
Compare result
randomization
Placebo group
Community trials
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Community trials, also called community intervention studies, are (mostly preventive) experimental studies with whole communities (such as cities or states) as experimental units; that is, interventions are assigned to all members in each of a number of communities
Old treatment Ethical approval •Sampling of patients
Randomization Compare result
New treatment
The end