Hello -
The following should be helpful:
Approaches to handling pharmacodynamic baseline responses
Chantaratsamon Dansirikul * Hanna E. Silber * Mats O. Karlsson
J/PK/PD 2008
:)
Chuanpu
From: owner-nmus...@globomaxnm.com [mailto:owner-nmus...@globomaxnm.com] On
Behalf Of Peiming Ma
Sent: Mond
Hi,
There are both pros and cons of using baseline observations as a covariate. We
presented four different options for how to handle baseline and investigated
estimation properties in the paper below. What we didn't look at, because it is
a very bad idea, is to use an baseline observation both
Dear NMusers,
I wonder if someone could help me to implement the OMEGA covariance matrix
below.
$OMEGA
0.09 ; PPV_VMAX
0.00 0.09 ; PPV_V1
0.00 0.00 0.09 ; PPV_V2
0.00 0.00 0.00 0.09 ; PPV_KD
0.00 0.01 0.00 0.00 0.09 ; PPV_BMAX
0.00 0.01 0.00 0.00 0.01 0.09 ; PPV
Hi,
From a purely technical point of view, you can use TIME in your $ERROR
record if you want to implement your drug effect as a direct effect on
top of the circadian rhythm (this type of model may or may not
appropriate, I leave you judge of that).
SinfS = ( 1 + Amplitude * sin ( (2*PI/Peri
Dear Katrin,
You still could code your model in $ERROR using TIME, as your diurnal
rhythm is proportional to baseline.
If you would like to explore indirect models, you could try the harmonic
approach as described in Chakraborty et al. 1999 -
http://europepmc.org/abstract/med/10533696; the
Hi Ana,
What you can do is rearrange your ETA order, ie, the full block and the rest as
with a separate '$OMEGA'
$OMEGA BLOCK(3)
0.09; V1
0.01 0.09 ;BMAX
0.01 0.01 0.09 ;KM
$OMEGA ...
Hope this helps,
Rudy
-Original Message-
From: o
Dear Ana,
If you only want to consider covariance between 3 parameters, I suggest you put
these three in an $OMEGA BLOCK(3) and list the remaining OMEGAs separately
outside the block.
Best,
Elke
-Original Message-
From: owner-nmus...@globomaxnm.com [mailto:owner-nmus...@globomaxnm.com]
Li,
It's worth pointing out that the typical IDR formulation assumes proportional
effect on response. That is, if the drug effect is inhibition of synthesis
(e.g Imax=0.5), a subject with baseline 100 will go to 50 and a subject with
baseline 1000 will go to 500. If your data is suggesting th
