Controlled clinical trials
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Control Clin Trials · Apr 2003
Randomized Controlled Trial Clinical TrialElicitation of prior distributions for a phase III randomized controlled trial of adjuvant therapy with surgery for hepatocellular carcinoma.
A randomized, controlled clinical trial of radioactive iodine tagged with lipiodol in patients with resected hepatocellular carcinoma was criticized for its early stopping and resulting small sample size. To clarify its results, a new, larger multicenter trial was therefore proposed. ⋯ They can also be used in Bayesian analyses, both at the interim stage(s) as well as at the end of the trial. We illustrate these analyses, assuming that the data resulting from the new trial was the same as that obtained in the earlier trial when it was stopped.
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Control Clin Trials · Aug 2001
Randomized Controlled Trial Clinical TrialThe inhaled Steroid Treatment as Regular Therapy in early asthma (START) study: rationale and design.
Although the beneficial effects of treatment with inhaled steroids in asthma are widely accepted, the role of early intervention in patients with mild asthma remains unsettled. Conventional efficacy trials are often of short duration and involve highly selected patient populations that exclude many patients typical of those encountered in routine clinical practice. Hence, a large "real-world" effectiveness study is needed to evaluate the benefits of early intervention with inhaled steroids in patients with mild, persistent asthma. ⋯ Lung function will be measured by spirometry using standardized techniques at 3-month intervals throughout the study, and bronchodilator reversibility will be measured annually. The primary outcome measures are the time to the first severe asthma-related event during the first 3 years of the study and the change in postbronchodilator forced expiratory volume in 1 second (FEV(1)) from baseline during the entire 5-year study period. These measures have been chosen to reflect the progression of mild asthma toward more severe asthma and the extent of irreversible airflow limitation, which should reflect the degree of airway remodeling.
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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 · Feb 2001
Randomized Controlled Trial Multicenter Study Comparative Study Clinical TrialCloseout of four phase II Vanguard trials and patient rollover into a large international phase III HIV clinical endpoint trial.
Large phase III clinical trials typically require many years of planning and preparation. During this time, proposed study methods and overall trial feasibility can be assessed in smaller pilot studies. However, the patients enrolled in these pilot studies are not routinely included in the larger study. ⋯ Specifically, the reconsent process, the data collection transition plan, and the steps taken to minimize bias due to differential reconsent according to the assigned treatment arm in the phase II trial are described. The procedures employed are relevant to the reconsent of patients for long-term follow-up at the completion of clinical trials. Control Clin Trials 2001;22:42-48
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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.