Sample size re-estimation in clinical trials.
نویسنده
چکیده
Adaptive clinical trials are becoming very popular because of their flexibility in allowing mid-stream changes of sample size, endpoints, populations, etc. At the same time, they have been regarded with mistrust because they can produce bizarre results in very extreme settings. Understanding the advantages and disadvantages of these rapidly developing methods is a must. This paper reviews flexible methods for sample size re-estimation when the outcome is continuous.
منابع مشابه
Sample size re-estimation for adaptive sequential design in clinical trials.
There is considerable interest in methods that use accumulated data to modify trial sample size. However, sample size re-estimation in group sequential designs has been controversial. We describe a method for sample size re-estimation at the penultimate stage of a group sequential design that achieves specified power against an alternative hypothesis corresponding to the current point estimate ...
متن کاملSample size re-estimation in an on-going NIH-sponsored clinical trial: the secondary prevention of small subcortical strokes experience.
BACKGROUND AND PURPOSE When planning clinical trials, decisions regarding sample size are often based on educated guesses of parameters, which may in fact prove to be over- or under-estimates. For example, after initiation of the SPS3 study, published data indicated that the recurrent stroke rates might be lower than initially planned for the study. Failure to account for this could result in a...
متن کاملCharacteristics of Clinical Trials in Iran: A Sample of 5000 Trials Registered in IRCT
Background and Objectives: A considerable number of clinical trials are conducted in Iran each year. Not much is known about the characteristics of them, this study aimed to investigate key characteristics of Iranian clinical trials. Methods: All clinical trial protocols registered in IRCT until November 2013 were selected. Text mining techniques were used to extract information from data t...
متن کاملA review and re-interpretation of a group-sequential approach to sample size re-estimation in two-stage trials
In this paper, we review the adaptive design methodology of Li et al. (Biostatistics 3:277-287) for two-stage trials with mid-trial sample size adjustment. We argue that it is closer in principle to a group sequential design, in spite of its obvious adaptive element. Several extensions are proposed that aim to make it even more attractive and transparent alternative to a standard (fixed sample ...
متن کاملImpact of misspecifying the distribution of a prognostic factor on power and sample size for testing treatment interactions in clinical trials
BACKGROUND Interaction in clinical trials presents challenges for design and appropriate sample size estimation. Here we considered interaction between treatment assignment and a dichotomous prognostic factor with a continuous outcome. Our objectives were to describe differences in power and sample size requirements across alternative distributions of a prognostic factor and magnitudes of the i...
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
برای دانلود متن کامل این مقاله و بیش از 32 میلیون مقاله دیگر ابتدا ثبت نام کنید
ثبت ناماگر عضو سایت هستید لطفا وارد حساب کاربری خود شوید
ورودعنوان ژورنال:
- Biometrical journal. Biometrische Zeitschrift
دوره 51 2 شماره
صفحات -
تاریخ انتشار 2009