Selecting one admission per year

[analyst_work]

I need to limit one admission per year, there can be multiple admissions for that one patient. I want to look across all admissions and then select one admission per year. Thank you!

Patient C	Adm 1	14-Jan-16	Include first admission
Patient C	Adm 2	6-May-17	Include (more than 365 days)
Patient C	Adm 3	5-Jun-17	Exclude (less than 365 days from Adm 2)
Patient D	Adm 1	14-Jan-16	Include first admission
Patient D	Adm 2	6-Jan-17	Exclude (less than 365 days from Adm 1)
Patient D	Adm 3	5-Jun-17	Include (more than 365 days from Adm 1)

[PeterClemmensen]

You have two different date variables here. What dates are to be considered? The to date from adm1 and the from date from adm2?

[analyst_work]

Updated the table above. Thanks!

[novinosrin]

Hi @analyst_work   Please review 

Patient D	Adm 1	12-Jan-16	14-Jan-16	Include first admission
Patient D	Adm 2	6-May-17	6-Jan-17	Exclude (less than 365 days from Adm 1)

How is the number of days between  14-Jan-16 and 6-May-17 is less than 365?

EDITED: Please ignore this post

[analyst_work]

Please see updated table above. Thanks!

[novinosrin · Accepted solution]

Hi @analyst_work  Thank you

data have;
infile cards truncover;
input patient & $20. adm & $6. date :date9.;*  out_date :date9.;
format date date9.  ;*out_date date9.;
cards;
Patient C	Adm 1	14-Jan-16	Include first admission
Patient C	Adm 2	6-May-17	Include (more than 365 days)
Patient C	Adm 3	5-Jun-17	Exclude (less than 365 days from Adm 2)
Patient D	Adm 1	14-Jan-16	Include first admission
Patient D	Adm 2	6-Jan-17	Exclude (less than 365 days from Adm 1)
Patient D	Adm 3	5-Jun-17	Include (more than 365 days from Adm 1)
;




data want;
set have;
by patient;
retain d;
if first.patient then do; d=date;f=1;end;
else if intck('day',d,date)>365 then do;
d=date;
f=1;
end;
if f;
drop f d;
run;

[ballardw]

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@analyst_work wrote:

I need to limit one admission per year, there can be multiple admissions for that one patient. I want to look across all admissions and then select one admission per year. Thank you!

Patient C	Adm 1	14-Jan-16	Include first admission
Patient C	Adm 2	6-May-17	Include (more than 365 days)
Patient C	Adm 3	5-Jun-17	Exclude (less than 365 days from Adm 2)
Patient D	Adm 1	14-Jan-16	Include first admission
Patient D	Adm 2	6-Jan-17	Exclude (less than 365 days from Adm 1)
Patient D	Adm 3	5-Jun-17	Include (more than 365 days from Adm 1)

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Any other rules? Is this supposed to be a random selection? First within period?

And do you actually have SAS date values or are your values currently character values that resemble dates?