Title | Time-varying latent effect model for longitudinal data with informative observation times. |
Publication Type | Journal Article |
Year of Publication | 2012 |
Authors | Cai, Na, Wenbin Lu, and Hao Helen Zhang |
Journal | Biometrics |
Volume | 68 |
Issue | 4 |
Pagination | 1093-102 |
Date Published | 2012 Dec |
ISSN | 1541-0420 |
Keywords | Algorithms, Biometry, Computer Simulation, Data Interpretation, Statistical, Epidemiologic Methods, Information Storage and Retrieval, Longitudinal Studies, Models, Statistical |
Abstract | In analysis of longitudinal data, it is not uncommon that observation times of repeated measurements are subject-specific and correlated with underlying longitudinal outcomes. Taking account of the dependence between observation times and longitudinal outcomes is critical under these situations to assure the validity of statistical inference. In this article, we propose a flexible joint model for longitudinal data analysis in the presence of informative observation times. In particular, the new procedure considers the shared random-effect model and assumes a time-varying coefficient for the latent variable, allowing a flexible way of modeling longitudinal outcomes while adjusting their association with observation times. Estimating equations are developed for parameter estimation. We show that the resulting estimators are consistent and asymptotically normal, with variance-covariance matrix that has a closed form and can be consistently estimated by the usual plug-in method. One additional advantage of the procedure is that it provides a unified framework to test whether the effect of the latent variable is zero, constant, or time-varying. Simulation studies show that the proposed approach is appropriate for practical use. An application to a bladder cancer data is also given to illustrate the methodology. |
DOI | 10.1111/j.1541-0420.2012.01794.x |
Alternate Journal | Biometrics |
Original Publication | Time-varying latent effect model for longitudinal data with informative observation times. |
PubMed ID | 23025338 |
PubMed Central ID | PMC3543780 |
Grant List | P01 CA142538 / CA / NCI NIH HHS / United States R01 CA051962 / CA / NCI NIH HHS / United States R01 CA085848 / CA / NCI NIH HHS / United States R01 CA140632 / CA / NCI NIH HHS / United States |
Time-varying latent effect model for longitudinal data with informative observation times.
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