RE: Dataset coding for baseline endogenous substance
Hi Brady,
Generally, you will just include the baseline measurement as time=0 and then
reference all other times from that time. So, if your baseline value was drawn
at 8AM on day 1 while the first dose was at 10AM, just set the baseline time as
0 and the first dose time as 2 (also assuming that your time is in hours). If
baseline is taken far before the next time, the only important part is that you
want the time between baseline and the next measurement to be more than ~5-fold
the auto-correlation time of your system.
>From there, you will estimate your A_0 values as you have seen other places.
>A general note that is not always covered in other discussions of endogenous
>substance PK: You want to make sure that your equations work so that A_0 is
>at steady state (usually). Often, you will not directly set A_0, but you will
>solve the equations for A_0 being steady-state and set it to the steady-state
>value.
Thanks,
Bill
Quoted reply history
From: [email protected] [mailto:[email protected]] On
Behalf Of Moffett, Brady S.
Sent: Tuesday, May 26, 2015 6:02 PM
To: [email protected]
Subject: [NMusers] Dataset coding for baseline endogenous substance
I am modeling a drug that is also an endogenous substance.
I have found quite a bit of information on modeling practices with endogenous
substances, but nothing on how to incorporate the baseline endogenous substance
value (DV) into the dataset.
The data is from clinical use, and the baseline values are not drawn at exactly
the same times prior to drug administration.
Any assistance would be appreciated! Thank you in advance...
Brady S Moffett, PharmD, MPH
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