enrollment date 12 months before and after a specific date - date

Question

enter image description hereI am trying to find persons by id who have continuous, 12 months enrollment before the hospitalization date and another 12 months after the hospitalization date. Each member will have one row.
This is using claim database in US. Any help is appreciated.
Example of the dataset:
ID Enr_date End_Date hosp_date
1 1/5/2004 1/6/2008 2/2/2006
2 .... and so on
3
4
id start_e end_e date_h
1 1/1/2005 1/1/2006 2/8/2008
1 2/3/2006 4/5/2013
2 5/7/2005 8/8/2006 4/5/2007
2 1/1/2007 2/2/2012
3 5/9/2005 5/9/2007 1/1/2007
3 6/4/2008 7/7/2012

Answer 1

assuming my last comments have answers there are many ways you can do this. Starting out it may be difficult to get outer joins, cross joins etc working in a way that's easy to understand. With a SAS macro we can break the problem down so it's easy to understand and do any debugging that may be necessary. Here's one approach that may work for you:
%macro hdates;
/* get number of hosp_dates */
proc sql noprint;
select count(*) into: cnt
from date where hosp_date ne .;
quit;
%let cnt = &cnt;
/* place hdates and ids into macro vars */
proc sql noprint;
select enrolid, hosp_date into: id_1 - :id_&cnt, : hdate_1 - :hdate_&cnt
from date;
quit;
proc delete data= hcov; run;
/* for each hdate id pair go through the dataset and test for 12 mo coverage
%do i = 1 %to &cnt;
data new;
set date;
if (enrolid = &&id_&i) then do;
preDays = "&&hdate_&i"d - start_date ;
postDays = end_date - "&&hdate_&i"d;
if (preDays >= 365 and postDays >= 365) then output;
end;
run;
proc append base = hcov data=new;run;
%end;
%mend hdates;
%hdates;

Answer 2

I work in claims data and I think I understand what you are trying to ask. I recommend making one table with the "condensed" enrollment ranges and another with the hospitalization dates. Then you may merge them together and keep only those patients who meet your criteria. The following code will condense the enrollment ranges (assuming good records):
PROC SORT DATA=dset_in; BY id enr_date end_date; RUN;
DATA enrollment (KEEP=id enroll_start enroll_stop);
SET dset_in;
FORMAT enroll_start enroll_stop DATE9.;
BY id enr_date end_date;
RETAIN enroll_start enroll_stop;
IF first.id THEN DO;
enroll_start=enr_date;
enroll_stop=end_date;
END;
ELSE IF enr_date-enroll_stop <= 1 THEN enroll_stop=end_date;
ELSE DO;
OUTPUT;
enroll_start=enr_date;
enroll_stop=end_date;
END;
IF last.id THEN OUTPUT;
RUN;
Then this code will keep only those patients with a hospitalization and 365 days enrollment before and after. If the hosp_claims dataset has more than 1 hospitalization per patient, sort then take the first obs per id after this step:
PROC SQL;
CREATE TABLE hosp_enrolled AS
SELECT DISTINCT a.id, a.hosp_dt, b.enroll_start, b.enroll_stop
FROM hosp_claims AS a, enrollment AS b
WHERE a.id=b.id AND b.enroll_start+365 <= a.hosp_dt <= enroll_stop-365;
QUIT;