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The National Institutes of Health (NIH) defines a clinical trial as “a research study in which one or more human subjects are prospectively assigned to one or more interventions (which may include placebo or other control) to evaluate the effects of those interventions on health-related biomedical or behavioral outcomes.” There are generally two types of clinical trials: controlled and uncontrolled. Uncontrolled trials lack a comparison group. Controlled trials involve two or more study treatments, at least one of which is a control treatment (i.e., a standard against which new treatments are measured). The main focus of this chapter is interventional trials including cohort (cross-sectional, case-control) studies and interventional trials, that is, intervention(s) applied to the study population synonymous with clinical trials in most texts. Dr. William Thomas Beaver was the clinical pharmacologist at Georgetown University who is credited with drafting the initial regulations defining “adequate and controlled” clinical studies. “Clinical trials are systematic experiments performed on human beings for the purpose of assessing the safety and/or efficacy of treatments or care procedures. The function of the controlled clinical trial is not the ‘discovery’ of a new drug or therapy. Discoveries are made in the animal laboratory, by chance observation, or at the bedside by an astute clinician. The function of the formal controlled clinical trial is to separate the relative handful of discoveries which prove to be true advances in therapy from a legion of false leads and unverifiable clinical impressions, and to delineate in a scientific way the extent of and the limitations which attend the effectiveness of drugs.” |
