NONMEM Users Network Archive

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Re: T in $DES

From: Dennis Fisher <fisher>
Date: Tue, 6 Jul 2021 07:28:57 -0700

Matts

I believe that the issue that you encountered is addressed in the NONMEM =
output. Look for this text:

(WARNING 48) DES−DEFINED ITEMS ARE COMPUTED ONLY WHEN EVENT =
TIME
 INCREASES. E.G., DISPLAYED VALUES ASSOCIATED WITH THE FIRST EVENT =
RECORD
 OF AN INDIVIDUAL RECORD ARE COMPUTED WITH (THE LAST ADVANCE TO) AN =
EVENT
 TIME OF THE PRIOR INDIVIDUAL RECORD.

The wording is arcane but the basic message is that, for each subject, =
the first values for DES computed entries are not what you expect.
Despite this, NONMEM is "doing the right thing".
I defer to Alison Boeckmann to explain the inner workings.

Dennis

Dennis Fisher MD
P < (The "P Less Than" Company)
Phone / Fax: 1-866-PLessThan (1-866-753-7784)
www.PLessThan.com




> On Jul 6, 2021, at 5:44 AM, Matts Kågedal =
<mattskagedal
>
> Hi all,
> I have a question regaring T in $DES.
> I have a time-varying covariate that is derived based on an explicit =
equation and then use in a differential equation.
> I got some funny results in the output table and investigated a bit =
further.
>
> I therefore derived T_DAY=T in $DES as below and output it in =
$TABLE.
> Why is T_DAY at TIME=0 equal to the time of the last observation for =
the patient? I was expecting it to be Zero (same as Time). Seems to be =
the same for all IDs in the dataset.
> Below is the output created in $TABLE including the "derived" variable =
T_DAY.
> Any advice would be appreciated.
> Matts Kågedal
>
> <image.png>
>
> <image.png>


Received on Tue Jul 06 2021 - 10:28:57 EDT

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