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Re: st: Fitting weibull to a survival curve


From   Lars Kroll <lars@climweb.de>
To   statalist@hsphsun2.harvard.edu
Subject   Re: st: Fitting weibull to a survival curve
Date   Thu, 09 Jun 2005 10:03:46 +0200

Try this if St is your Percentage of survival and t your time:

* Your Data
input t St
0 100
1 90
2 30
4 0
end
* Solution
gen death = 0
replace death = St[_n-1]-St[_n] if _n>1
ctset t death2
cttost, clear
streg , dist(weibull)

(if there are more than one group simply add a variable group and use the group option of ctset)
Hope this helps
Lars

____________________________
Lars E. Kroll
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Giulio Rizzoli schrieb:


I have several survival curves from medical papers, describing the follow-up time of patients on the x axis and the % survival on the y axis.
I need to fit a weibull model to this curves to summarize them with 2 parameters , a shape and a scale parameter.
How can be practically done in Stata.
I have to input the time variable and the % survival ?
It is possible to stset these data ?
How should the weibull command be written?
Thanks for help
Giulio Rizzoli , Padova (italy)
Giulio Rizzoli MD FETCS
Cardiochirurgia Padova
tel. 049 821-2408
fax 049 821-2409
e-mail giulio.rizzoli@unipd.it
web: http.//web.tiscali.it/grizzoli

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