Contemporary clinical trials
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Contemp Clin Trials · Nov 2008
Multicenter StudyRecruitment of minority and underserved populations in the United States: the Centers for Population Health and Health Disparities experience.
The recruitment of minority and underserved individuals to research studies is often problematic. The purpose of this study was to describe the recruitment experiences of projects that actively recruited minority and underserved populations as part of The Centers for Population Health and Health Disparities (CPHHD) initiative. ⋯ Recruitment of minority and underserved populations to clinical trials is necessary to increase study generalizbility and reduce health disparities. Our results demonstrate the importance of flexible study designs which allow adaptation to recruitment challenges. These experiences also highlight the importance of involving community members and reducing participant burden to achieve success in recruiting individuals from minority and underserved populations.
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Contemp Clin Trials · Sep 2008
Predictive checking for Bayesian interim analyses in clinical trials.
Bayesian methodologies have been used for interim analyses of clinical trial data. In Bayesian interim analyses, decisions regarding the continuation of a trial are guided by a Bayesian model or indices, e.g., the predictive probability derived from it that specifies the conditions under which the clinical trial results might be judged sufficiently convincing to allow early stopping. ⋯ In this paper we describe the use of both prior- and posterior- predictive checking approaches as a diagnostic tool for assessing the reliability of the model or indices on which the decision making is based. The proposed approach is illustrated with three examples, one of which is a simulation.
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Contemp Clin Trials · Sep 2008
Chinese authors do need CONSORT: reporting quality assessment for five leading Chinese medical journals.
Only a few Chinese medical journals have recommended CONSORT in their "Instruction for authors or Guide for authors". This study aims to evaluate the reporting quality of randomized controlled trials (RCTs) published in the five leading Chinese medical journals indexed by MEDLINE. ⋯ The reporting quality of RCTs published in the five leading Chinese medical journals is low. Chinese journals should adopt the CONSORT statement to improve the reporting quality of Chinese randomized controlled trials.
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Contemp Clin Trials · Sep 2008
Estimating the proportion of studies missing for meta-analysis due to publication bias.
A potential problem with meta-analysis concerns missing studies due to publication bias. This paper focuses on one subtype of publication bias, namely selection bias (studies with unfavorable outcomes tend to be suppressed), wherein the main interest is in determining the proportion of unpublished studies. ⋯ The new method is very simple and its results are comparable to other meta-analytic methods. However, in contrast to existing methods, it can be applied to the study-specific outcomes alone.
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We propose a Bayesian approach to monitor clinical trials with clustered binary outcomes using multivariate probit models. Our monitoring is based on the calculated probability of the reduced incidence rate using a new treatment compared with the standard treatment greater than a target improvement under different prior scenarios for the treatment effect. We develop a Bayesian sampling algorithm for posterior inference allowing missing values in the outcomes. We illustrate our method using a published early trail of inhaled nitric oxide therapy in premature infants.