Dear Svend,
thanks a lot for your kind reply and for the example.
I beg your pardon for having been not clear enough.
Actually, I would like to compare the significant difference of all the
incidence rates.
Let'say:
Patients enrolled to receive drug A reported 200 relapses during a 6-month
follow-up;
Patients enrolled to receive drug B reported 150 relapses during a 6-month
follow-up;
Patients enrolled to receive drug C reported 220 relapses during a 6-month
follow-up.
I have in mind something like multiple comparisons with Bonferroni's
correction via ANOVA with continuous variables, but I do not know whether a
similar procedure does exist in the dichotomous variables setting (I have
unsuccessfully scanned some epidemiology textbook searching for this issue,
but I was not able to find nothing more than chi2 and two-sample
comparisons).
Thanks a lot agin and Kind Regards,
Carlo
-----Messaggio originale-----
Da: [email protected]
[mailto:[email protected]] Per conto di Svend Juul
Inviato: gioved� 3 aprile 2008 17.56
A: [email protected]
Oggetto: Re: st: multile comparison among incidence rates
Carlo wrote:
I would like to compare three incidence rates (the only effectiveness end
point available) concerning three group of patients with the same disease,
treated with three different drugs and followed-up for six months.
Is there any way to do it in Stata/SE 9.2? Is there any reference about your
hints?
=========================================================
Carlo,
It is not quite clear to me what you mean by "compare three incidence
rates". Is it a question of significant difference or estimation of
incidence rate ratios or rate differences? And do you want to compare
B vs A and C vs A only, or do you also want to compare B vs C?
Below I used -ci- to estimate the individual incidence rates and
-poisson- to estimate incidence rate ratios (imagine that -agecat-
represents the drugs to be compared).
webuse dollhill3.dta
by agecat, sort: ci deaths, poisson exposure(pyears)
xi: poisson deaths i.agecat, exposure(pyears) irr
Hope this helps
Svend
________________________________________________________
Svend Juul
Institut for Folkesundhed, Afdeling for Epidemiologi
(Institute of Public Health, Department of Epidemiology)
Vennelyst Boulevard 6
DK-8000 Aarhus C, Denmark
Phone, work: +45 8942 6090
Phone, home: +45 8693 7796
Fax: +45 8613 1580
E-mail: [email protected]
_________________________________________________________
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