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# Re: st: Analysis admissions after liver transplant

 From Nick Cox To statalist@hsphsun2.harvard.edu Subject Re: st: Analysis admissions after liver transplant Date Tue, 3 Jan 2012 18:43:48 +0000

```Spelling out

year + (real(substr(quarter, 2, 1)) - 1) / 4

step by step gives:

substr(quarter, 2, 1) is "1" "2" "3" "4"

real() maps that to 1 2 3 4

subtract 1 and divide by 4 gives 0 0.25 0.5 0.75

Nick

On Tue, Jan 3, 2012 at 6:23 PM, Matthew White <mwhite@poverty-action.org> wrote:
> Hi Anwar,
>
> See:
>
> SJ-2-1  pr0004  . . . . . . . . . . Speaking Stata:  How to move step
> by: step        . . . . . . . . . . . . . . . . . . . . . . . . . . .
> . . .  N. J. Cox        Q1/02   SJ 2(1):86--102
>           (no commands)
> Also, -year + (real(substr(quarter, 2, 1)) - 1) / 4- is used to add
> quarter to year for a single number.
>
> Best,
> Matt
>
> On Tue, Jan 3, 2012 at 12:44 PM, Dudekula, Anwar <dudekulaan@upmc.edu> wrote:
>> Hi Matt,
>>
>> I am sorry to post  this basic question .
>>
>> But how does this logic that you wrote work
>>
>> 1)(generate firsttransplant = year + (real(substr(quarter, 2, 1)) - 1) /4 if livertransplant == "yes"
>> 2)bysort pseudoid (firsttransplant): replace firsttransplant = firsttransplant[1]
>> 3)keep if year + (real(substr(quarter, 2, 1)) - 1) / 4 > firsttransplant

From: owner-statalist@hsphsun2.harvard.edu
[owner-statalist@hsphsun2.harvard.edu] on behalf of Matthew White
[mwhite@poverty-action.org]

>>
>> generate firsttransplant = year + (real(substr(quarter, 2, 1)) - 1) /
>> 4 if livertransplant == "yes"
>> bysort pseudoid (firsttransplant): replace firsttransplant = firsttransplant[1]
>> keep if year + (real(substr(quarter, 2, 1)) - 1) / 4 > firsttransplant

On Mon, Dec 19, 2011 at 12:25 PM, Dudekula, Anwar <dudekulaan@upmc.edu> wrote:

>>> I am here with posting a de-identified data for patients with liver transplant
>>>
>>> --The patients  with liver disease get admitted multiple times to the hospital.During one of the admission, they get liver transplant based on their degree of sickness.They can get re-admitted to the hospital after liver transplant for  complications related to transplant.To explore this issues, we want to evaluate the admissions after they get the liver transplant
>>>
>>> --For example  patient with pseudoid-1 gets liver transplant in 4th quarter .That patient gets admitted three times subsequently but patient with pseudiid-9 gets liver transplant during second admission and has three successive admissions after that
>>>
>>> --So I want to pick up the observations after the liver transplant( eventhough they may not get a liver transplant during that admission)
>>>
>>>
>>> The data contains
>>> --pseudoid, whcih is unique for the patient
>>> --sysid is unique for each quarter of a year
>>> --Q1,Q2,Q3,Q4 are 4 quarters of the year
>>>
>>>
>>>
>>>        pseudoid     sysid   year    quarter     livertransplant |
>>>     |------------------------------------------------------------|
>>>  1. | pseudoid-1   0220890   2008         Q4    yes              |
>>>  2. | pseudoid-1   0229499   2009         Q2    no           |
>>>  3. | pseudoid-1   0234526   2009         Q3    no               |
>>>  4. | pseudoid-2   0234997   2010         Q2    no               |
>>>  5. | pseudoid-3   0248508   2008         Q1   yes               |
>>>     |------------------------------------------------------------|
>>>  6. | pseudoid-4   0227009   2008         Q2   no                |
>>>  7. | pseudoid-4   0483263   2008         Q3   yes               |
>>>  8. | pseudoid-5   0483419   2008         Q2   no                |
>>>  9. | pseudoid-6   0228531   2008         Q1   yes               |
>>>  10. | pseudoid-7   0227324   2009         Q3   no                |
>>>     |------------------------------------------------------------|
>>>  11. | pseudoid-9   0227325   2008         Q1   no                |
>>>  12. | pseudoid-9   0227326   2008         Q2   yes               |
>>>  13. | pseudoid-9   0227327   2008         Q3   no                |
>>>  14. | pseudoid-9   0482471   2008         Q4   no                |
>>>  15. | pseudoid-9  0231492    2009         Q2   no                |
>>>

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```