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Incorporating intermediate binary responses into interim analyses of clinical trials : a comparison of four methods.

Whitehead, Anne and Sooriyarachchi, Marina Roshini and Whitehead, John and Bolland, Kim (2008) Incorporating intermediate binary responses into interim analyses of clinical trials : a comparison of four methods. Statistics in Medicine, 27 (10). pp. 1646-1666.

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Abstract

In clinical trials with a long period of time between randomization and the primary assessment of the patient, the same assessments are often undertaken at intermediate times. When an interim analysis is conducted, in addition to the patients who have completed the primary assessment, there will be those who have till then undergone only intermediate assessments. The efficiency of the interim analysis can be increased by the inclusion of data from these additional patients. This paper compares four methods of increasing information based on model-free estimates of transition probabilities to incorporate intermediate assessments from patients who have not completed the trial. It is assumed that the observations are binary and that there is one intermediate assessment. The methods are the score and Wald approaches, each with the log-odds ratio and probability difference parameterizations. Simulations show that all four approaches have good properties in moderate to large sample sizes.

Item Type: Article
Journal or Publication Title: Statistics in Medicine
Uncontrolled Keywords: binary data • longitudinal data • score test • sequential clinical trial • Wald test
Subjects: Q Science > QA Mathematics
Departments: Faculty of Science and Technology > Mathematics and Statistics
ID Code: 33514
Deposited By: Mr Richard Ingham
Deposited On: 25 May 2010 14:06
Refereed?: Yes
Published?: Published
Last Modified: 09 Oct 2013 14:50
Identification Number:
URI: http://eprints.lancs.ac.uk/id/eprint/33514

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