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GMDS 2012: 57. Jahrestagung der Deutschen Gesellschaft für Medizinische Informatik, Biometrie und Epidemiologie e. V. (GMDS)

Deutsche Gesellschaft für Medizinische Informatik, Biometrie und Epidemiologie

16. - 20.09.2012, Braunschweig

Sample size calculations for crossover designs based on a given precision

Meeting Abstract

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  • Benjamin Lang - Boehringer Ingelheim Pharma GmbH & Co. KG, Biberach an der Riss, Deutschland
  • Frank Fleischer - Boehringer Ingelheim Pharma GmbH & Co. KG, Biberach an der Riss, Deutschland

GMDS 2012. 57. Jahrestagung der Deutschen Gesellschaft f黵 Medizinische Informatik, Biometrie und Epidemiologie e.V. (GMDS). Braunschweig, 16.-20.09.2012. D黶seldorf: German Medical Science GMS Publishing House; 2012. Doc12gmds147

DOI: 10.3205/12gmds147, URN: urn:nbn:de:0183-12gmds1470

Published: September 13, 2012

© 2012 Lang et al.
This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by-nc-nd/3.0/deed.en). You are free: to Share – to copy, distribute and transmit the work, provided the original author and source are credited.


Outline

Text

In early phase crossover trials sample sizes are often not based on formal power calculations but on a given precision for the resulting confidence interval. In many cases such sample size calculations are performed by using software packages that are only able to deal with parallel and paired designs. Thus, if 2󫎾 or other higher-order crossover studies are going to be performed, often the actual sample size needed is only approximated by using a paired design for the calculations. Hence all within-subject comparison studies have to rely on the sample size of a paired design, thereby neglecting the actual trial design. We extended the set of possible study designs allowing for different crossover design options (similar as done within the R package PowerTOST) thereby enabling us to incorporate the actual study design into the calculations. We compared resulting sample sizes and precisions for various crossover designs with the corresponding paired design. Our results show that although the calculations for the actual crossover design is more accurate, calculations using the paired design in general yield a conservative sample size. Additionally a quanitification is provided for the error made when using the paired design for the sample size calculation.