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Re: st: Tests for trends in RCT subgroups (-metan-, -meta-, other?)


From   Joseph Coveney <jcoveney@bigplanet.com>
To   Statalist <statalist@hsphsun2.harvard.edu>
Subject   Re: st: Tests for trends in RCT subgroups (-metan-, -meta-, other?)
Date   Sat, 11 Jun 2005 11:41:35 +0900

Matthew Sydes wrote: 

> I am interested in performing tests of trend in ordered subgroups from a
> single randomised controlled trial.  It is possible to use meta-analysis
> commands for this purpose, pretending that each subgroup is a separate
> trial.  I have investigated the -meta- and -metan- commands.  However,
> their tests for heterogeneity only seem to deal in global tests rather
> than tests for trends.
> 
Like numbers-at-risk on KM plots, subgroup trend tests are an issue I often
wrangle with and find that I can solve only outside of Stata (albeit
somewhat unsatisfactorily and unloggable fashion).

Any help on how I may address this matter within Stata would be much
appreciated.

--------------------------------------------------------------------------------

Could you describe in more detail what it is that you're trying to do?  

It seems that you have only aggregate-level data for the single study.  Is the 
problem that the outcome is continuous and the article shows only summary 
statistics for the subgroups?  If so, then take a look at -aovsum-, a user-
written command from John R. Gleason (-findit aovsum-).  The help file for it 
illustrates its use in combination with -anova- to "Test for linear trend in 
dose, and for deviations from linear trend" in an example.  

If the outcome is binary and the article provides counts (or proportions and 
total sample size), then wouldn't conventional contingency table methods or 
logistic regression work?

Joseph Coveney

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