Journal ArticleDOI
Adaptive sample size calculations in group sequential trials.
Walter Lehmacher,Gernot Wassmer +1 more
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TLDR
A method for group sequential trials that is based on the inverse normal method for combining the results of the separate stages is proposed, which enables data-driven sample size reassessments during the course of the study.Abstract:
A method for group sequential trials that is based on the inverse normal method for combining the results of the separate stages is proposed. Without exaggerating the Type I error rate, this method enables data-driven sample size reassessments during the course of the study. It uses the stopping boundaries of the classical group sequential tests. Furthermore, exact test procedures may be derived for a wide range of applications. The procedure is compared with the classical designs in terms of power and expected sample size.read more
Citations
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Multiple Comparisons Using R
TL;DR: In this article, the multcomp package is used for multiple comparisons with a control and all pairwise comparisons with the same pairwise comparison, under the assumption of heteroscedasticity.
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Effect of Early vs Delayed Initiation of Renal Replacement Therapy on Mortality in Critically Ill Patients With Acute Kidney Injury: The ELAIN Randomized Clinical Trial
Alexander Zarbock,John A. Kellum,Christoph Schmidt,Hugo Van Aken,Carola Wempe,Hermann Pavenstädt,Andreea Boanta,Joachim Gerß,Melanie Meersch +8 more
TL;DR: To determine whether early initiation of RRT in patients who are critically ill with AKI reduces 90-day all-cause mortality, a single-center randomized clinical trial of 231 critically ill patients with KDIGO stage 2 found that more patients in the early group recovered renal function by day 90.
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Sample size calculations in randomised trials: mandatory and mystical
TL;DR: The branding of trials as unethical on the basis of an imprecise sample size calculation process might be acceptable if investigators use methodological rigor to eliminate bias, properly report to avoid misinterpretation, and always publish results to avert publication bias.
Journal ArticleDOI
Phase III Randomized Study of Bendamustine Compared With Chlorambucil in Previously Untreated Patients With Chronic Lymphocytic Leukemia
Wolfgang Knauf,Toshko Lissichkov,Ali Aldaoud,Anna Marina Liberati,Javier Loscertales,Raoul Herbrecht,Gunnar Juliusson,Gerhard Postner,Liana Gercheva,Stefan Goranov,Martin Becker,Hans Joerg Fricke,Françoise Huguet,Ilaria Del Giudice,Peter S. Klein,Lothar Tremmel,Karlheinz Merkle,Marco Montillo +17 more
TL;DR: Bendamustine offers significantly greater efficacy than chlorambucil, and a manageable toxicity profile, when used as first-line therapy in patients with advanced CLL.
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Adaptive design methods in clinical trials – a review
Shein-Chung Chow,Mark Chang +1 more
TL;DR: Several commonly considered adaptive designs in clinical trials are reviewed and some examples concerning the development of Velcade intended for multiple myeloma and non-Hodgkin's lymphoma are given.
References
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Larry V. Hedges,Ingram Olkin +1 more
TL;DR: In this article, the authors present a model for estimating the effect size from a series of experiments using a fixed effect model and a general linear model, and combine these two models to estimate the effect magnitude.
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TL;DR: In this paper, the authors present a model for estimating the effect size from a series of experiments using a fixed effect model and a general linear model, and combine these two models to estimate the effect magnitude.
Journal ArticleDOI
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Journal ArticleDOI
Discrete sequential boundaries for clinical trials
K. K. Gordon Lan,David L. DeMets +1 more
TL;DR: In this article, the authors proposed a more flexible method to construct discrete sequential boundaries based on the choice of a function, a*(t), which characterizes the rate at which the error level ac is spent.
Journal ArticleDOI
Group sequential methods in the design and analysis of clinical trials
TL;DR: In this article, a group sequential design is proposed to divide patient entry into a number of equal-sized groups so that the decision to stop the trial or continue is based on repeated significance tests of the accumulated data after each group is evaluated.
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