How to find the most recent dose date prior to AE start date

[yahoo0806]

Hi all,

I'm trying to write a SAS program to find the most recent dose date prior to the AE start date. 

In the exposure data, some all subjects are having the same number of exposure visits. Also in AE data, a subject can have multiple AE onset date.

So how should I write my program so that I can find the most recent dosing date prior to each AE onset date?

Many thanks!!

[PaigeMiller]

Show us a portion of your data, following this method: https://communities.sas.com/t5/SAS-Communities-Library/How-to-create-a-data-step-version-of-your-dat...

[yahoo0806]

Thank you I actually figured out how to do it: need to transpose the data first, then use array to pick up.

[Kurt_Bremser]

Please supply example data (in usable form, a data step with datalines), and what you expect to get out of it. Post your data step code by using the "little running man" icon.