Dear Daping,
In order to provide more than just general comments it would be useful to get
some more information.
- What is the purpose of developing the PopPK model?
- What is the medical condition/disease?
- What is the relation between plasma concentration and cl
Hi all,
Creation of VPCs is a way to assess if simulated data generated by the
model is compatible with observed data.
VPCs are usually based on parameter point estimates of the model. Sometimes
parameter uncertainty is also accounted for in the generation of VPCs
(PPCs) where each simulated repli
Matts,
The way I see the CI's around the point estimates provided in the VPC can
help provide a useful indication of model robustness, especially in regards
to the impact of random effects components, in that portion of your model.
Especially for heterogeneous data (or even all rich data for that
Hi Devin and Matts,
Of interest, we had similar internal discussion within our department about
this topic quite recently.
I would agree with Devin that it is preferable to include parameters
uncertainty in a VPC, especially if they are used for relevant decision making.
It may result on large
Dear Matts,
For assessing model adequacy, I would use the point estimates. If your best
model is contradicted by the data by showing a poor VPC, there seems little
meaning in trying to include uncertainty. There could be a role for VPCs with
uncertainty though. If you plan to perform simulation
Hi All,
I have done it both ways (with and without including parameter uncertainty).
It is important to note that the resulting VPC intervals are degenerate when
you don’t take into account parameter uncertainty. That is, with infinite
sample size these intervals will collapse to the p
Dear Jacob,
Thanks a lot for your comments. I am also very appreciated the reference
you sent to me.
Regarding to your questions, the purpose of this study was to explain the
PK variability of an immunosuppresant drug in pediatric population post
hematopoietic stem cell transplantation. The age r
