NONMEM Users Network Archive

Hosted by Cognigen

CrcL or Cr in pediatric model

From: Bonate, Peter <Peter.Bonate>
Date: Mon, 12 Jan 2009 15:51:58 -0600

I have an interesting question I'd like to get the group's collective =
opinion on. I am fitting a pediatric and adult pk dataset. I have =
fixed weight a priori to its allometric exponents in the model. When I =
test serum creatinine and estimated creatinine clearance equation as =
covariates in the model (power function), both are statistically =
significant. CrCL appears to be a better predictor than serum Cr (LRT =
= 22.7 vs 16.7). I have an issue with using CrCL as a predictor in =
the model since it's estimate is based on weight and weight is already =
in the model. Also, there might be collinearity issues with CrCL and =
weight in the same model, even though they are both significant. Does =
anyone have a good argument for using CrCL in the model instead of serum =


Pete bonate

Peter L. Bonate, PhD, FCP
Genzyme Corporation
Senior Director
Clinical Pharmacology and Pharmacokinetics
4545 Horizon Hill Blvd
San Antonio, TX 78229 USA
phone: 210-949-8662
fax: 210-949-8219
crackberry: 210-315-2713
alea jacta est - The die is cast.

Julius Caesar

Received on Mon Jan 12 2009 - 16:51:58 EST

The NONMEM Users Network is maintained by ICON plc. Requests to subscribe to the network should be sent to:

Once subscribed, you may contribute to the discussion by emailing: