Creating a Variable using Dates

[jcapua2]

Hello,

data have;

patient_num	Procedure_Date	Organ	Multiorgan
patient33	1/24/2000	Heart	No
patient33	5/13/2003	Kidney	Yes
patient33	5/13/2003	Skin	Yes
patient34	5/7/2007	Lung	No
patient34	5/27/2009	Heart	No

data want;

patient_num	Procedure_Date	Organ	Multiorgan	Previous_organ
patient33	1/24/2000	Heart	No	No
patient33	5/13/2003	Kidney	Yes	Yes
patient33	5/13/2003	Skin	Yes	Yes
patient34	5/7/2007	Lung	No	No
patient34	5/27/2009	Heart	No	Yes

I want to create a new variable that flags whether a particular patient has had a previous organ procedure. For example, patient34 has 2 different Procedure_date, with a later Procedure_date that occurred with a different organ, flagging that later row with Previous_organ='Yes' but the prior row (the first Procedure_date) Previous_organ='No.'

Also, for patient33, with 3 Procedure_date, but the last 2 dates occurred on the same date but with different organs. It flags the last 2 dates as Previous_organ='Yes' but the prior row (the first Procedure_date) Previous_organ='No.'

Is there any way to do this in SQL or SAS data step?

[Reeza]

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@jcapua2 wrote:

Hello,

data have;

patient_num	Procedure_Date	Organ	Multiorgan
patient33	1/24/2000	Heart	No
patient33	5/13/2003	Kidney	Yes
patient33	5/13/2003	Skin	Yes
patient34	5/7/2007	Lung	No
patient34	5/27/2009	Heart	No

data want;

patient_num	Procedure_Date	Organ	Multiorgan	Previous_organ
patient33	1/24/2000	Heart	No	No
patient33	5/13/2003	Kidney	Yes	Yes
patient33	5/13/2003	Skin	Yes	Yes
patient34	5/7/2007	Lung	No	No
patient34	5/27/2009	Heart	No	Yes

I want to create a new variable that flags whether a particular patient has had a previous organ procedure. For example, patient34 has 2 different Procedure_date, with a later Procedure_date that occurred with a different organ, flagging that later row with Previous_organ='Yes' but the prior row (the first Procedure_date) Previous_organ='No.'

Also, for patient33, with 3 Procedure_date, but the last 2 dates occurred on the same date but with different organs. It flags the last 2 dates as Previous_organ='Yes' but the prior row (the first Procedure_date) Previous_organ='No.'

Is there any way to do this in SQL or SAS data step?

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Look up first and last BY GROUP processing. Most of the questions you've asked can be answered using these techniques in a data step.