Large clinical trials and registries-clinical research institutes
This chapter highlights the purpose of clinical trial, registry, or outcome study-to estimate what is likely to happen to the next patient if one treatment strategy or the other is chosen. To assess the degree to which the proposed study enhances the ability to understand what will happen to the next patient, the investigator must be aware of an array of methodological and clinical issues. Although this task requires substantial expertise and experience, the issues are considered in a broad framework. The simplest but most essential concepts for understanding the relevance of a clinical study to practice are validity and generalizability. The manner in which the results of clinical research are reported can profoundly influence the perception of practitioners evaluating the information to decide which therapies to use. A clinical trial will produce a different degree of enthusiasm about the therapy tested when the results are presented in the most favorable light. To guard against this problem, investigators should report clinical outcome trials in terms of both relative and absolute risk reductions, including confidence intervals for point estimates. As experience with multiple clinical trials accumulates, some general concepts seem worth emphasizing. These generalities do not always pertain, but they serve as useful guides to the design or interpretation of trials. Failure to consider these general principles often leads to a faulty design and failure of the project. © 2007 Elsevier Inc. All rights reserved.
