Calculate age from dates based on a condition

amarikow57 — Mon, 25 Jan 2021 22:52:59 GMT

My dataset has multiple visit dates for a given patient (in long format). Let's say:

PATIENT_ID VIST VISIT_DATE DOB DIAGNOSIS

1 1 01/12/2011 02/15/1997 1

1 2 02/17/2011

1 3 06/23/2011 02/15/1997

1 4 11/12/2011

2 1 01/13/2011 09/21/1995

2 2 09/17/2011 0

3 1 02/03/2011

3 2 04/15/2011 11/19/2001

3 3 07/06/2011 11/19/2001 1

4 1 01/29/2011

4 2 05/30/2011

4 3 08/22/2011 07/16/2003 0

4 4 12/01/2011

I want to (a) make sure that I have the birthdate repeated for the corresponding PATIENT_ID, then I want to (b) create an AGE_AT_DIAG variable for when they were assessed. That is VISIT_DATE - DOB when DIAGNOSIS = 1 or DIAGNOSIS = 0, and then repeated for the corresponding ID. How can I go about this?

Re: Calculate age from dates based on a condition

Reeza — Mon, 25 Jan 2021 23:04:42 GMT

1. Fill in birth date for all missing records

proc sql;
create table temp1 as
select *, max(dob) as DOB_ALL
from have
group by patient_Id
order by 1, 2, 3;
quit;

2. Calculate age at diagnosis, adding on to step 1 (replaces step1)

proc sql;
create table temp1 as
select *, max(dob) as DOB_ALL,
          yrdif(dob_all, visit_date, 'AGE') as AGE_DIAGNOSIS
from have
group by patient_Id
order by 1, 2, 3;
quit;

3. Merge main table with filtered table for diagnosis = 1

data want;
merge have temp1 (where=(diagnosis=1) keep = (patient_ID DOB_ALL AGE_DIAGNOSIS));
by patient_ID;
run;

@amarikow57 wrote:

My dataset has multiple visit dates for a given patient (in long format). Let's say:

PATIENT_ID VIST VISIT_DATE DOB DIAGNOSIS

1 1 01/12/2011 02/15/1997 1

1 2 02/17/2011

1 3 06/23/2011 02/15/1997

1 4 11/12/2011

2 1 01/13/2011 09/21/1995

2 2 09/17/2011 0

3 1 02/03/2011

3 2 04/15/2011 11/19/2001

3 3 07/06/2011 11/19/2001 1

4 1 01/29/2011

4 2 05/30/2011

4 3 08/22/2011 07/16/2003 0

4 4 12/01/2011

I want to (a) make sure that I have the birthdate repeated for the corresponding PATIENT_ID, then I want to (b) create an AGE_AT_DIAG variable for when they were assessed. That is VISIT_DATE - DOB when DIAGNOSIS = 1 or DIAGNOSIS = 0, and then repeated for the corresponding ID. How can I go about this?

topic Calculate age from dates based on a condition in SAS Data Management

Calculate age from dates based on a condition

Re: Calculate age from dates based on a condition