Hi, I have a dataset that looks like this: Patient_ID Admission_date Comorbidity A 14/05/2011 1 B 21/04/2011 0 C 30/06/2011 2 C 23/09/2011 3 C 22/06/2012 1 D 25/04/2011 2 D 26/04/2012 1 E 01/12/2011 1 E 04/12/2011 2 E 29/04/2012 3 E 30/04/2013 2 It's a large dataset of patients with different admission dates and different recorded comorbidity scores. I am interested in the sum (patient level) of their scores for the period of 365 days before admission. If the patient was not admitted before, then the score is 0. If the previous admission is more than 365 days ago, the score is also 0. If there is more than 1 admission in the previous year, it's the sum of the scores. In the table above, the results would look like this: Patient_ID Admission_date Comorbidity Past_Score A 14/05/2011 1 0 B 21/04/2011 0 0 C 30/06/2011 2 0 C 23/09/2011 3 2 C 22/06/2012 1 5 D 25/04/2011 2 0 D 26/04/2011 1 2 E 01/12/2011 1 0 E 04/12/2011 2 1 E 29/04/2012 3 3 E 30/04/2013 2 0 I tried many different approaches (proc means, changing the dataset to wide,...) but I am struggling to find a working solution. I am using SAS Enterprise Guide, version 7.1 Any help will be greatly appreciated! Many thanks.
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