Some Alternatives to Asymptotic Tests for the Analysis of Pharmacogenetic Data Using Nonlinear Mixed Effects Models
Nonlinear mixed effects models allow investigating individual differences in drug concentration profiles (pharmacokinetics) and responses. Pharmacogenetics focuses on the genetic component of this variability. Two tests often used to detect a gene effect on a pharmacokinetic parameter are (1) the Wa...
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| Published in: | Biometrics Vol. 68; no. 1; pp. 146 - 155 |
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| Main Authors: | , , , |
| Format: | Journal Article |
| Language: | English |
| Published: |
Malden, USA
Blackwell Publishing Inc
01.03.2012
Wiley-Blackwell Blackwell Publishing Ltd |
| Subjects: | |
| ISSN: | 0006-341X, 1541-0420, 1541-0420 |
| Online Access: | Get full text |
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| Summary: | Nonlinear mixed effects models allow investigating individual differences in drug concentration profiles (pharmacokinetics) and responses. Pharmacogenetics focuses on the genetic component of this variability. Two tests often used to detect a gene effect on a pharmacokinetic parameter are (1) the Wald test, assessing whether estimates for the gene effect are significantly different from 0 and (2) the likelihood ratio test comparing models with and without the genetic effect. Because those asymptotic tests show inflated type I error on small sample size and/or with unevenly distributed genotypes, we develop two alternatives and evaluate them by means of a simulation study. First, we assess the performance of the permutation test using the Wald and the likelihood ratio statistics. Second, for the Wald test we propose the use of the F‐distribution with four different values for the denominator degrees of freedom. We also explore the influence of the estimation algorithm using both the first‐order conditional estimation with interaction linearization‐based algorithm and the stochastic approximation expectation maximization algorithm. We apply these methods to the analysis of the pharmacogenetics of indinavir in HIV patients recruited in the COPHAR2‐ANRS 111 trial. Results of the simulation study show that the permutation test seems appropriate but at the cost of an additional computational burden. One of the four F‐distribution‐based approaches provides a correct type I error estimate for the Wald test and should be further investigated. |
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| Bibliography: | http://dx.doi.org/10.1111/j.1541-0420.2011.01665.x ark:/67375/WNG-JSQK1D14-V ArticleID:BIOM1665 istex:1A05F44F59B4854EA60B0184EC89DD186C050298 SourceType-Scholarly Journals-1 ObjectType-Feature-1 content type line 14 ObjectType-Article-1 ObjectType-Feature-2 content type line 23 |
| ISSN: | 0006-341X 1541-0420 1541-0420 |
| DOI: | 10.1111/j.1541-0420.2011.01665.x |