NONMEM Users Network Archive

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[NMusers] RE: Stepwise covariate modeling

From: Luann Phillips <Luann.Phillips_at_cognigencorp.com>
Date: Tue, 29 Oct 2019 15:00:50 +0000

Hi,

If all of the individual predictions are the same for the model with the co=
variate and without the covariate, then it sounds like the original model i=
s at a local minimum instead of a global minimum.

Best regards,
Luann

From: owner-nmusers_at_globomaxnm.com <owner-nmusers_at_globomaxnm.com> On Behalf=
 Of Singla, Sumeet K
Sent: Tuesday, October 29, 2019 10:00 AM
To: nmusers_at_globomaxnm.com
Subject: [NMusers] Stepwise covariate modeling

Hi!

I am performing stepwise covariate modeling using PsN feature in Pirana. I =
am getting some covariates which are statistically reducing OFV significant=
ly, however, when I include those covariates in the PK model, the results I=
 am getting are exactly similar to what I am getting in my base model, i.e.=
 there is no difference in individual predictions or pop predictions or any=
 other diagnostic plots. So, does that mean I should move forward WITHOUT i=
ncluding those covariates as they don't seem to be explaining inter-individ=
ual variability despite scm telling me that they are statistically signific=
ant?

Regards,

Sumeet K. Singla
Ph.D. Candidate
Division of Pharmaceutics and Translational Therapeutics
College of Pharmacy | University of Iowa
Iowa City, Iowa
sumeet-singla_at_uiowa.edu<mailto:sumeet-singla_at_uiowa.edu>
518.577.5881



Received on Tue Oct 29 2019 - 11:00:50 EDT

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