RE: [NMusers] Describing Omega that includes both BSV and IOV

From: Hyeong-Seok Lim <mdhslim_at_gmail.com>
Date: Fri, 4 Sep 2015 11:49:55 +0900

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,

 

 

==========================
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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: mdlhs_at_amc.seoul.kr <mailto:mdlhs_at_amc.seoul.kr> , =
mdhslim_at_gmail.com <mailto:mdhslim_at_gmail.com>

 

==========================
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==================

 

From: owner-nmusers_at_globomaxnm.com [mailto:owner-nmusers_at_globomaxnm.com] =
On Behalf Of 이소정
Sent: Friday, September 4, 2015 11:13 AM
To: nmusers_at_globomaxnm.com
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:sjyi_at_snu.ac.kr> sjyi_at_snu.ac.kr



Received on Thu Sep 03 2015 - 22:49:55 EDT

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