Title | Simultaneous inference for longitudinal data with detection limits and covariates measured with errors, with application to AIDS studies |
Publication Type | Journal Article |
Year of Publication | 2004 |
Authors | WU, LANG |
Journal | Statistics in Medicine |
Volume | 23 |
Pagination | 1715–1731 |
Date Published | jun |
ISSN | 1097-0258 |
Keywords | EM algorithm, Gibbs sampler, HIV, mixed-effects model |
Abstract | In AIDS studies such as HIV viral dynamics, statistical inference is often complicated because the viral load measurements may be subject to left censoring due to a detection limit and time-varying covariates such as CD4 counts may be measured with substantial errors. Mixed-effects models are often used to model the response and the covariate processes in these studies. We propose a unified approach which addresses the censoring and measurement errors simultaneously. We estimate the model parameters by a Monte-Carlo EM algorithm via the Gibbs sampler. A simulation study is conducted to compare the proposed method with the usual two-step method and a naive method. We find that the proposed method produces approximately unbiased estimates with more reliable standard errors. A real data set from an AIDS study is analysed using the proposed method. Copyright © 2004 John Wiley & Sons, Ltd. |
URL | http://onlinelibrary.wiley.com/doi/10.1002/sim.1748/abstract |
DOI | 10.1002/sim.1748 |