Controlled clinical trials
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Control Clin Trials · Dec 1997
Review Comparative StudyMeta-analysis of randomized trials: looking back and looking ahead.
Meta-analyses as currently practiced are usually retrospective. They can be made more rigorous by developing a protocol that incorporates prospectively the elements that are usually necessary in a well-designed trial. ⋯ Once the large trials have been completed, they could be brought together within the framework of a meta-analysis to estimate the overall treatment effect with greater confidence and to explore the effects in various subgroups. This article explores the value and limitations of meta-analyses and suggests ways of improving their conduct and interpretation.
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Control Clin Trials · Jun 2001
Randomized Controlled Trial Clinical TrialThe prehospital treatment of status epilepticus (PHTSE) study: design and methodology.
Status epilepticus is a neurological emergency that is typically first encountered and managed in the prehospital environment. Although aggressive pharmacological treatment of status epilepticus is well established in the emergency department and hospital settings, the relative risks and benefits of active therapy for status epilepticus in the prehospital setting are not known. ⋯ The initial phase of the PHTSE study began in January 1994 and was completed in February 1999 after the successful enrollment of 205 patients into the three treatment arms. In this paper, we describe the rationale for the conceptualization of the study and details of the study design and methodology, and emphasize some aspects of study implementation that are unique to research involving the emergency medical system.
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Control Clin Trials · Oct 2004
The utility of partial cross-over designs in early phase randomized prevention trials.
In this note, we outline the benefits of a partial cross-over design for a class of experiments where the interest is the cumulative effect of dose versus placebo. The goal of our design strategy is to answer several complex question efficiently in a phase II setting with a minimal number of assumptions with an eye towards planning a phase III study.
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Control Clin Trials · Jun 2003
Randomized Controlled Trial Clinical TrialPerceptions of equipoise are crucial to trial participation: a qualitative study of men in the ProtecT study.
Recruitment to trials is known to be difficult. Previous research suggests that a crucial factor may be participants' difficulty with the concept of randomization. This study explored patients' perceptions of randomization and reasons for consent or refusal to participate in the ProtecT study (a randomized trial of surgery, radiotherapy, and monitoring for localized prostate cancer). ⋯ Belief in clinical equipoise was key to participants' consent to randomization. Ensuring patients understand and accept equipoise may thus increase their readiness to consent to participate in trials. A priority for future research is to focus on the provision and presentation of suitable and effective trial information, concentrating in particular on the neglected concept of clinical equipoise.
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Control Clin Trials · Apr 2000
Randomized Controlled Trial Clinical TrialImpact of the Hawthorne effect in a longitudinal clinical study: the case of anesthesia.
Clinical research can be influenced by many factors that are capable of invalidating results, and one of these factors is known as the Hawthorne effect: the mere awareness of being under observation can alter the way in which a person behaves. In experimental research this effect can be the undesired effect of the experiments themselves, and the stronger its presence, the greater it can influence the results. In anesthesia practice, owing to the particular emotional condition of a patient facing a surgical operation, the Hawthorne effect could be especially strong. ⋯ The size of the effect, as measured by the odds ratio, remains unchanged when controlling for potential confounding factors. The study has enabled us to demonstrate the presence of the Hawthorne effect in clinical research. Therefore, the Hawthorne effect should be acknowledged and accounted for in the design of a study and in the interpretation of results.