Hi Folks,
I'm trying to create a data of patients who fulfills the following criteria:
Keep | IF: First observation of the patient |
Delete | IF: Less than 12 mo since the last eligible data by patients |
In other words:
The observation needs to be compared to the last eligible data. For instance, for the second subject (PAT_ID=2), third row is eligible because time passed since the last eligible observation is longer than 12 mo. The last eligible observation is the first row. Because second row was deleted due to its ineligibility.
DATA HAVE;
INPUT PAT_ID DATE_VISITS DIFF_VISITS;
CARDS;
1 15391 .
1 15573 5.98
1 15945 12.22
2 15406 .
2 15586 5.92
2 15798 6.96
3 15775 .
3 16139 11.96
3 16321 5.98
4 15439 .
4 15621 5.97
4 16349 23.92
5 15438 .
5 15655 7.13
5 16019 11.96
6 15349 .
6 15558 6.87
6 15768 6.9
;
If you wonder why do this?
The biological marker concerned here is not highly dynamic over time. Therefore, you would not want to make a premature decision based on the observations captured over less than 12 months in between at least.
DATA HAVE;
INPUT PAT_ID DATE_VISITS DIFF_VISITS;
format DATE_VISITS date9.;
CARDS;
1 15391 .
1 15573 5.98
1 15945 12.22
2 15406 .
2 15586 5.92
2 15798 6.96
3 15775 .
3 16139 11.96
3 16321 5.98
4 15439 .
4 15621 5.97
4 16349 23.92
5 15438 .
5 15655 7.13
5 16019 11.96
6 15349 .
6 15558 6.87
6 15768 6.9
;
data want;
set have;
by PAT_ID;
retain d;
if first.pat_id then do;output; d=DATE_VISITS;end;
else do;
dif=intck('month',d,DATE_VISITS);
if dif>=12 then do;output;d=DATE_VISITS;end;
end;
run;
DATA HAVE;
INPUT PAT_ID DATE_VISITS DIFF_VISITS;
format DATE_VISITS date9.;
CARDS;
1 15391 .
1 15573 5.98
1 15945 12.22
2 15406 .
2 15586 5.92
2 15798 6.96
3 15775 .
3 16139 11.96
3 16321 5.98
4 15439 .
4 15621 5.97
4 16349 23.92
5 15438 .
5 15655 7.13
5 16019 11.96
6 15349 .
6 15558 6.87
6 15768 6.9
;
data want;
set have;
by PAT_ID;
retain d;
if first.pat_id then do;output; d=DATE_VISITS;end;
else do;
dif=intck('month',d,DATE_VISITS);
if dif>=12 then do;output;d=DATE_VISITS;end;
end;
run;
Pleasure is mine:)
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