Hi, I'm hoping that someone will be able to help. I would like to compare how covariates associate with the risk of a binary outcome during two periods. Period 1 will be non-exposure to a treatment and period 2 will be exposure to a treatment. The same individuals will be examined in each group but I want to be able to compare the association of certain covariates between the two groups to see if there is a treatment interaction. I've looked at case-crossover designs and time series analysis and don't think that they are suitable. The cohort has longitudinal data so individuals will go onto treatment at different times and the effect of the treatment needs to be administered for a while before it has an effect. The reason why I cannot just go ahead with an exposed vs unexposed design is that most individuals in the cohort end up on the treatment eventually and the unexposed group is very small and lacks power for a meaningful comparison.
Is there anyway to compare the same individuals during different exposure times and to look at the effect of different covariates under the exposed and unexposed conditions? Thanks for you help, Natalie ----- Natalie Van Zuydam PhD Student University of Dundee nvanzuy...@dundee.ac.uk -- View this message in context: http://r.789695.n4.nabble.com/Stats-question-Comparison-of-the-same-individuals-during-two-exposure-times-tp4636732.html Sent from the R help mailing list archive at Nabble.com. ______________________________________________ R-help@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.
