https://communities.sas.com/t5/Statistical-Procedures/how-to-account-for-duration-of-drug-exposure/m-p/331924#M17529 <P>What about including it as a variable? But it may also be time dependent so consider checking the time dependency aspect.&nbsp;</P> <P>&nbsp;</P> Sun, 12 Feb 2017 04:18:10 GMT Reeza 2017-02-12T04:18:10Z https://communities.sas.com/t5/Statistical-Procedures/how-to-account-for-duration-of-drug-exposure/m-p/331913#M17527 <P>I am studying impact of a medication on survival outcomes. each patient was on this particular medication for different duration of time and outcomes depend on duration of exposure. so i think analysing by users vs non-users will not be adequate. How do I account for duration of exposure into the survival analysis - cox proportional hazard model?</P> Sun, 12 Feb 2017 02:32:54 GMT https://communities.sas.com/t5/Statistical-Procedures/how-to-account-for-duration-of-drug-exposure/m-p/331913#M17527 shivaa 2017-02-12T02:32:54Z https://communities.sas.com/t5/Statistical-Procedures/how-to-account-for-duration-of-drug-exposure/m-p/331924#M17529 <P>What about including it as a variable? But it may also be time dependent so consider checking the time dependency aspect.&nbsp;</P> <P>&nbsp;</P> Sun, 12 Feb 2017 04:18:10 GMT https://communities.sas.com/t5/Statistical-Procedures/how-to-account-for-duration-of-drug-exposure/m-p/331924#M17529 Reeza 2017-02-12T04:18:10Z https://communities.sas.com/t5/Statistical-Procedures/how-to-account-for-duration-of-drug-exposure/m-p/331931#M17531 <P>thanks for the reply.&nbsp;</P><P>Could I use the 'usage of drug' as a time dependent co-variate in the model and will that account for duration of exposure. I know it solves the problem of immortal time bias..</P> Sun, 12 Feb 2017 07:01:59 GMT https://communities.sas.com/t5/Statistical-Procedures/how-to-account-for-duration-of-drug-exposure/m-p/331931#M17531 shivaa 2017-02-12T07:01:59Z