SMS scnews item created by Andrew Mathas at Sun 11 Aug 2013 2158
Expiry: 16 Aug 2013
Calendar1: 16 Aug 2013 1200-1300
CalLoc1: AGR Seminar
CalTitle1: AGR Seminar: Sequential meta-analysis or how many more studies do we need?
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Sequential meta-analysis or how many more studies do we need?
Professor Elena Kulinskaya (University of East Anglia)
La Trobe University
Meta-analysis has applications for the design of new trials, with a view of finding the definite answer to the existing research question. Existing methods are based on group sequential methods developed for single trials and start with the calculation of a required information size. This works satisfactorily within the framework of fixed effects meta-analysis (FEM), but conceptual difficulties arise in the random effects model (REM). We briefly review several existing approaches. One approach applying sequential meta-analysis to design is "Trial Sequential Analysis' (TSA), developed by Wetterslev, Thorlund, Brok, Gluud and others from the Copenhagen Trial Unit. In TSA, information size is based on the required sample size of a single new trial which, in REM, is obtained by simply inflating it in comparison to FEM. However, this is not sufficient as, depending on the amount of heterogeneity, a minimum of several new trials may be indicated, and the total number of new patients needed may be substantially reduced by planning an even larger number of small trials. We provide explicit formulae to determine the requisite minimum number of trials and their sample sizes within this framework, which also exemplify the conceptual difficulties referred to. All these points are illustrated with two practical examples, including the well-known meta-analysis of magnesium for myocardial infarction. This is a joint work with John Wood, UCL.
Dr Andriy Olenko
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