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Meta‐analysis combining parallel and cross‐over clinical trials. II: Binary outcomes
Author(s) -
Curtin François,
Elbourne Diana,
Altman Douglas G.
Publication year - 2002
Publication title -
statistics in medicine
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.996
H-Index - 183
eISSN - 1097-0258
pISSN - 0277-6715
DOI - 10.1002/sim.1206
Subject(s) - estimator , statistics , meta analysis , random effects model , correlation , cross over , marginal model , standard error , odds ratio , mathematics , computer science , econometrics , regression analysis , medicine , geometry
Abstract We examine different methods to pool binary outcomes used both in parallel and cross‐over trials. Odds ratio (OR) estimators obtained from joint conditional probabilities in cross‐over trials, such as the Mantel–Haenszel and Peto methods, are compared to an OR estimator using marginal results of cross‐over trials. When there is correlation between the outcomes in the two cross‐over periods, joint conditional ORs differ from marginal ORs and cannot be combined with OR estimates from parallel trials. The marginal OR estimate is independent of the between‐period correlation and it includes a correction for cross‐over correlation in the variance estimate. As its computation is similar in cross‐over and parallel trials, it is the method of choice to pool results from parallel and cross‐over trials in a combined design meta‐analysis. Copyright © 2002 John Wiley & Sons, Ltd.