[R] Selecting First Incidence from Longitudinal Data

[David Winsemius]

On Feb 23, 2013, at 6:28 AM, Tasnuva Tabassum wrote:

> I have a longitudinal competing risk data of the form:
> 
> ID    COMPL  SEX   HEREDITY
> 1     0       1      2
> 1     0       1      2
> 1     3       1      2
> 2     0       0      1
> 2     1       0      1
> 2     2       0      1
> 2     2       0      1
> 3     0       0      1
> 3     0       0      1
> 3     0       0      1
> 3     0       0      1
> 3     2       0      1
> 4     0       1      2
> 4     0       1      2.
> 
> Where, COMPL= health complication of diabetic patients which has value
> labels   as  0= no complication,1=coronary heart disease, 2=retinopathy, 3=
> nephropathy.
> 
> 
> I want to select only the first complication that occurred to each patient.
> What R function can I use?
> 

> dat[ with(dat, ave(COMPL, ID, FUN=function(x) cumsum(x>0) ) ) ==1,]
   ID COMPL SEX HEREDITY
3   1     3   1        2
5   2     1   0        1
12  3     2   0        1



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David Winsemius
Alameda, CA, USA