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From | "Newton Cheng" <ncheng@aafp.org> |
To | <statalist@hsphsun2.harvard.edu> |
Subject | Re: st: Time-dependent variables and the simon & makuch method (Out of office: Vacation ) |
Date | Wed, 09 Oct 2013 05:52:38 -0500 |
To whom it may concern, I am out of office. Will get back to your inqury on the week of 9/10/2012 >>> Florian Posch <florian.posch@meduniwien.ac.at> 10/09/13 05:51 >>> Dear Statalisters, your help would be very much appreciated on the following: I'm working on a dataset where I am modeling the impact of a time-dependent variable (the onset of thrombosis during follow-up) on survival. This analysis works fine with stsplit, and is pretty much the same as done in the Stanford Heart Transplant data example: The Stata Journal (2004) 4 , Number 2, pp. 221�222 Stata tip 8: Splitting time-span records with categorical time-varying covariates Again, my analysis works well for the Cox model, Kaplan-Meier survival curves, and the logrank-test (as illustrated in the Staa journal paper above). However, some recent reviews postulate that time-dependent covariates can validly be used in the Cox model but that is is INAPPROPRIATE to use them in Kaplan-Meier survival curves and the logrank test. These reviews suggest that the appropriate substitute methods in this setting are the Simon & Makuch plot (substitute for Kaplan-Meier curves), and the Mantel-Byar test (substitute for the logrank test). Searching the web I found some posts in forums and a couple of papers on Pubmed which say that Stata has implemented these methods, however, I could not find such a package on the SSC or anywhere else in Stata. A prior post regarding this issue on statalist remained unanswered: http://www.stata.com/statalist/archive/2010-05/msg00079.html Do you know where I can find these analysis methods for Stata? Thank you very much in advance for your input! Flo Florian Posch, MSc MD PhD Student Medical University of Vienna * * For searches and help try: * http://www.stata.com/help.cgi?search * http://www.stata.com/support/faqs/resources/statalist-faq/ * http://www.ats.ucla.edu/stat/stata/ * * For searches and help try: * http://www.stata.com/help.cgi?search * http://www.stata.com/support/faqs/resources/statalist-faq/ * http://www.ats.ucla.edu/stat/stata/