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[NMusers] NONMEM Unexpected result with the $LEVEL statement

From: Dumortier, Thomas <thomas.dumortier_at_novartis.com>
Date: Tue, 13 Aug 2019 20:39:55 +0000

Hello

I would like to model inter-study variability on the of the inter-subject v=
ariability with NONMEM 74
A subject belongs to a study, therefore those two random effects are nested

Following the instruction, I code as below, where ETA8 is at the subject l=
evel and ETA9 is at the study (STUD) level.

$INPUT ID STUD TIME TIM2 TAD NT CMT EVID MDV BLOQ AMT DOSE RATE LIDV=
=DV LNDV WT0 TRT1S TRT2S PAS0
...
$PK
...
    TVF1 = THETA(8) + ETA(8) + ETA(9)
    F1 = (EXP(TVF1)/(1+EXP(TVF1)))
...
$LEVEL STUD=(9[8])

The fit with NONMEM 743 (fortran compliler) seems correct and the estimates=
 for the variance (OMEGA) of ETA8 and for ETA9 are provided.
But when looking at the ETA9 values (the empirical bayes estimates), I noti=
ce that

(1) Different subjects of the same study have different ETA9 values, whil=
e I would expect that all subjects of a study have same ETA9 value

(2) The ETA9 value is proportional to the ETA8 value (ie, plotting ETA8 v=
ersus ETA9 from all subjects of all studiers results in all points on the s=
ame diagonal line)

Am I coding incorrectly ?

Any help would be more than welcome

Many thanks
Thomas Dumortier



Thomas Dumortier

Director Pharmacometrics

Novartis Pharma AG

Postfach

CH-4002 Basel

SWITZERLAND



Phone +41 61 3240946

Fax +41 61 3241246

thomas.dumortier_at_novartis.com<mailto:thomas.dumortier_at_novartis.com>




Received on Tue Aug 13 2019 - 16:39:55 EDT

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