R help - Jan 2009 - Welcome to the "R-help" mailing list

On Thu, 29 Jan 2009 20:55:19 +0100
  r-help-request at r-project.org wrote:
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Bishwa S Koirala
Department of Economics
University of New Mexico
Albuquerque, NM 87131

Bishwa S Koirala <bkoirala at unm.edu> [Thu, Jan 29, 2009 at 08:56:17PM
CET]:
>> You must know your password to change your options (including changing
>> the password, itself) or to unsubscribe.  It is:
>>
It is definitely a good idea to change your password ASAP.


-- 
Johannes H?sing               There is something fascinating about science. 
                              One gets such wholesale returns of conjecture 
mailto:johannes at huesing.name  from such a trifling investment of fact.
http://derwisch.wikidot.com         (Mark Twain, "Life on the
Mississippi")

Dear R users:
    Analysis of the impact of a time-dependent covariate (GVHD or use of steroid
after bone marrow transplantation) on two competing endpoints (invasive fungal
infection and death) is frequently encountered in the setting of BMT data. Coxph
package can be used as the following:
    for the analysis of GVHD:
 > gvhd -> coxph(Surv(start,stop,status = =1) ~ GVHD, data=bmt.data)
    and the data should be edited as the following:
          patient start stop status(IFI) GVHD
             1     0      15     0         0
             1     15     35     1         1
             2     0      12     0         0
             2     12     20     2         1
             3     0      30     2         0
             4     0      100    0         0
             5     0      25     0         0
             5     25     100    0         1
   similarly, for steroid:
     > steroid -> coxph(Surv(start,stop,status = =1) ~ steroid,
data=bmt.data)
    and the data was edited as the following:
          patient start stop status(IFI) steroid
             1     0      16     0         0
             1     16     35     1         1
             2     0      13     0         0
             2     13     20     2         1
             3     0      14     0         0
             3     14     30     2         1
             4     0      100    0         0
             5     0      21     0         0
             5     21     100    0         1
 
I wonder how can I analyze the two risk factors (GVHD and steroid) concurrently?
And how to edit the data.
How can I manage it if a third baseline risk factor(age for example) was
included?
 
 Thanks 
 Yours sincerely Ping Zhang 
 Feb 24 2009
 
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