RE: 95% prediction interval and $OMEGA
Just to elaborate slightly on this last suggestion. If you use a $MSFI to
input your parameters, use TRUE=FINAL to use the final, as opposed to the
initial, estimates from that preceding run. If $MSFI is not used, TRUE=FINAL
has no meaning.
Mats
Mats Karlsson, PhD
Professor of Pharmacometrics
Div. of Pharmacokinetics and Drug Therapy
Dept. of Pharmaceutical Biosciences
Faculty of Pharmacy
Uppsala University
Box 591
SE-751 24 Uppsala
Sweden
phone +46 18 471 4105
fax +46 18 471 4003
[EMAIL PROTECTED]
Quoted reply history
-----Original Message-----
From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On
Behalf Of Mouksassi Mohamad-Samer
Sent: Friday, June 06, 2008 22:14
To: [EMAIL PROTECTED]; [email protected]
Subject: RE: [NMusers] 95% prediction interval and $OMEGA
Hello Kelong,
Did you try to put TRUE=FINAL in the $simulation record.
I suggest also to input you parameters using MSFI
Bests,
Samer
-----Original Message-----
From: [EMAIL PROTECTED] on behalf of Han, Kelong
Sent: Thu 6/5/2008 21:49
To: [email protected]
Subject: [NMusers] 95% prediction interval and $OMEGA
Dear NONMEM users,
I am trying to calculate and plot the 95% prediction interval (PI) for a
single-subject multiple-dosing PO dataset by simulating 1000 DV values.
It seems that bigger initial estimate of omega ($OMEGA) leads to wider 95%
prediction band. I understand that OMEGA directs the variability in
"ERR(1)" in single-subject data, but I am still confused.
Could anyone help me pick up a $OMEGA to calculate 95% PI, or solve this
problem in another way? Thanks!
Below is the control stream (the best-fit THETA values were used as
initials):
--------------------------------------------------
$DATA po.csv IGNORE=C
$INPUT ID TIME CONC=DV AMT MDV CMT
$SUBROUTINE ADVAN2 TRANS2
$PK
CL = THETA(1)
V = THETA(2)
KA = THETA(3)
S2 = V
F1 = 1
$ERROR
IPRED=F
Y=F+ERR(1)
$THETA (0.398)
$THETA (64.3)
$THETA (0.425)
$OMEGA 1.2
$SIMULATION (324422) SUBPROBLEMS=1000
$ESTIMATION METHOD=0 NOABORT MAXEVAL=9999 PRINT=0
$COVARIANCE
$TABLE TIME DV IPRED NOPRINT NOHEADER FILE=
---------------------------------------------------------
Any input would be greatly appreciated.
Thanks!
Sincerely
--
Kelong Han
PhD student