Dear Nick,
Thank you.
Compliance= whether patients did take their drugs within a certain
range rate or not, defined as 95-110% of prescribed drugs on monthly
basis, in this cohort.
Kindly find below new example with pillcount variable.
studyid visit pillcount pc2_24 pc36_104
1027 2 0
1027 4 0
1027 8 0
1027 12 0
1027 16 0
1027 20 0
1027 24 0 0
1027 36 0
1027 52 0
1027 78 0 0
1029 2 0
1029 4 0
1029 8 0
1029 12 0
1029 16 0
1029 20 0
1029 24 0 0
1029 36 0
1029 52 0
1029 78 1
1029 104 0 1
ID 1027 did drop out before week 104 on treatment but still counted her.
ID 1029 has example of patient coming to all visits.
Hope this helps?
Thank you again and best regards
ziad
On Tue, Aug 19, 2008 at 10:33 AM, Nick Cox <[email protected]> wrote:
> You should keep away from -egen, count()-.
>
> What does the help say?
>
> count(exp) (allows by varlist:) creates a constant (within varlist)
> containing the number of nonmissing observations of exp.
>
> Your exp (i.e. expression) is -pillcount-. So you are counting whether
> -pillcount- is non-missing. 1 is non-missing. 0 is non-missing. Any
> other non-missing value is non-missing. All observations with any of
> these non-missing values will be counted.
>
> That is, I gather, not at all what you want.
>
> I am less able to work out precisely what you do want. I could make some
> guesses but I think it is better if you explain. Do remember that many
> of us are not biostatisticians or medics and so, like me, may be fuzzy
> on what on earth compliance is.
>
> Your examples do not include any with data for the key variable
> -pillcount-.
>
> Nick
> [email protected]
>
> Ziad El-Khatib
>
> I have cohort dataset monitoring patients' compliance to drugs over 11
> time points (weeks 2, 4, 8, 12, 16, 20, 24, 36, 52, 78 and 104 after
> starting on drugs).
> I want to look at the persistence of their compliance over weeks 2-24
> versus 36-104, i.e. OR of not missing any pill at all over all this
> visits between weeks 2-24 versus 36-104.
>
> At every visit I coded pillcount as 0/1: 1 if patient was not
> compliant versus 0: if patient was compliant.
>
> Now trying to create pc2_24 for weeks 2 to 24, and pc36_104 for week
> 36 to 104 to code them as 0/1 (compliant/not compliant).
>
> I tried
> egen pc2_24=count(pillcount),by(studyid), if visit>0&visit<25
>
> So got
>
> studyid visit pc2_24
> 1003 2 1
> 1003 4 1
> 1003 8 1
> 1003 12 1
> 1003 16 1
> 1003 20 1
> 1003 24 1
> 1005 2 1
> 1005 4 1
> 1005 8 1
>
>
> But I want the result to look like:
> studyid visit pc2_24
> 1003 2
> 1003 4
> 1003 8
> 1003 12
> 1003 16
> 1003 20
> 1003 24 1
> 1005 2
> 1005 4
> 1005 8
> 1005 12
> 1005 16
> 1005 20
> 1005 24 1
>
>
> so only to show number 0 or 1 at the last visit, whether visit number
> 24, 20 , or else that is <24
>
>
> *
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> * http://www.stata.com/help.cgi?search
> * http://www.stata.com/support/statalist/faq
> * http://www.ats.ucla.edu/stat/stata/
>
*
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