Randomized Clinical Trials Questions and answers.

Definition of Randomized Clinical Trial Prospective study in which two or more groups are randomly assigned with at least one given an intervention usually a novel treatment and one comparison(control) group. Only used to study presumed positive effects no negative effects (unethical) Key Design Features of RCT Controls concurrent with experiment group RANDOMIZATION Often utilize blinding and placebos Randomization the best defense against bias, in which each individual is given a fair, random chance of selection Single Blind Study Only the patient is unaware if they are in the treatment or the control group Double Blind Study Both the patient and the investigator are unaware if the patient is in the treatment or control group Triple Blind Study The patient, investigator and statisticians are all unaware of which patients are in the control and treatment groups Placebo an inert substance or condition that may be administered instead of a presumed active agent, such as a drug, to see if it triggers the effects believed to characterize the active agent Placebo effect experimental results caused by expectations alone; any effect on behavior caused by the administration of an inert substance or condition, which is assumed to be an active agent Equipoise Randomized clinical trials should have about an equal chance of success and failure, however, in practice we would not be doing a clinical trial if we didn't think the new drug or procedure would be effective Measures of Association in RCT Risk, Risk Rate, Risk Ratio, Risk Difference Advantages of RCT Gold Standard, likely to show causation rather than association, revolutionary Disadvantages of RCT Patients and doctors don't like the idea of a control group. Can't test negative exposures because it is unethical. Lengthy, expensive, difficult. Intent to Treat Analysis of clinical trial results that includes all data from participants in the groups to which they were randomized even if they never received the treatment. If based on compliance it would become an observational study and would be subject to bias and confounding.