Re: st: Fitting weibull to a survival curve

[Lars Kroll <lars@climweb.de>]

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

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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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