RE: Describing Omega that includes both BSV and IOV
Dear SoJeong Yi,
Sometime we cannot estimate the variances for IIV and IOV separately, although
we have multiple dosing data within each subject.
At that time, the alternative could be to combine the IIV and IOV to a single
random effect parameter, which is the way you have done.
In this case, the random effect parameter can be described as “random effect
parameter reflecting both IIV and IOV”, and so on.
Best regards,
=============================================================================================
Hyeong-Seok Lim MD PhD
Associate Professor
Department of Clinical Pharmacology and Therapeutics, Asan Medical Center,
University of Ulsan
88, Olympic-ro 43-gil, Songpa-gu, Seoul 138-736, Republic of Korea
Tel: +82-2-3010-4613
Fax: +82-2-3010-4623
LinkedIn: http://kr.linkedin.com/pub/hyeong-seok-lim/28/926/848
Email: [email protected] <mailto:[email protected]> , [email protected]
<mailto:[email protected]>
=============================================================================================
Quoted reply history
From: [email protected] [mailto:[email protected]] On
Behalf Of 이소정
Sent: Friday, September 4, 2015 11:13 AM
To: [email protected]
Subject: [NMusers] Describing Omega that includes both BSV and IOV
Dear all,
Currently I’m summarizing the NONMEM estimates of population PK for writing a
manuscript.
However, I wonder how to describe the omega which includes both between-subject
variability and inter-occasional variability.
The code of ‘variability’ is followed below,
$PK
IF(OCC.EQ.1) IOV = ETA(8)
IF(OCC.EQ.2) IOV = ETA(9)
IF(OCC.EQ.3) IOV = ETA(10)
….
KA = THETA(9) * EXP(IOV) (--> In final model, PK parameter was estimated like
this)
; KA = THETA(9) * EXP(ETA(4)+IOV) (--> When I used this code, there were some
problems (boundary error, large RSE (>80%), very small estimate of BSV and so
on) )
; KA = THETA(9) * EXP(ETA(4)) (--> when I used BSV only, the OFV is quite
higher than upper two cases, so I thought that IOV should be considered. )
$OMEGA BLOCK(1) SAME
$OMEGA BLOCK(1) SAME
$OMEGA BLOCK(1) 0.3
In this case, the individual eta was re-calculated in one subject according to
occasion, isn’t it?
Then, how should I describe this ‘variability’ and estimate of omega in a
manuscript?
(i.e., between subject variability containing inter-occasional variability? Or
any other appropriate term?)
I will appreciate if someone give any advice. Thanks in advance.
Best regards,
SoJeong Yi
SoJeong Yi, Ph.D
Department of Clinical Pharmacology and Therapeutics,
Seoul National University College of Medicine and Hospital
101 Daehak-ro, Jongno-gu, Seoul 110-744, Korea
Tel: 82-2-740-8291
Fax: 82-2-742-9252
C.P: 82-10-3178-4133
E-mail: <mailto:[email protected]> [email protected]