Abstract Details
Activity Number:
|
195
|
Type:
|
Contributed
|
Date/Time:
|
Monday, August 5, 2013 : 10:30 AM to 12:20 PM
|
Sponsor:
|
Section on Statistics and the Environment
|
Abstract - #309622 |
Title:
|
Diagnostics to Assess Toxicokinetic-Toxicodynamic Models
|
Author(s):
|
Xia Xu*+ and Philip Dixon
|
Companies:
|
Merck Research Laboratories and Iowa State Univ
|
Keywords:
|
toxicokinetics ;
survival analysis ;
diagnostics ;
proportional hazard ;
Hyalella azteca
|
Abstract:
|
In ecotoxicology studies, toxicokinetic-toxicodynamic (TKTD) models are increasingly being used to relate toxicant concentration to survival. These have a toxicokinetic component that specifies a model for toxicant uptake and elimination and a toxicodynamic component that specifies a model for the relationship between internal body concentration of toxicant and the hazard rate. Often, the toxicodynamic model is a proportional hazards model. We develop diagnostic methods to assess the appropriateness of the toxicokinetic and hazard models. A log-cumulative hazard plot is used to assess visually the proportional hazard assumption. This can be further evaluated by an approximate test based on a linear regression. If the proportional hazard assumption is valid, a plot of toxicant concentration against the average of log cumulative hazard for each concentration assesses the kinetic model. The use of these diagnostic tools is illustrated by fitting and evaluating a TKTD model for Hyalella azteca survival during and after exposure to copper sulfate and sodium pentachlorophenol.
|
Authors who are presenting talks have a * after their name.
Back to the full JSM 2013 program
|
2013 JSM Online Program Home
For information, contact jsm@amstat.org or phone (888) 231-3473.
If you have questions about the Continuing Education program, please contact the Education Department.
The views expressed here are those of the individual authors and not necessarily those of the JSM sponsors, their officers, or their staff.
Copyright © American Statistical Association.