Longitudinal latent variable models given incompletely observed biomarkers and covariates. (4th July 2016)

• Record Type: Journal Article
• Authors: Ren, Chunfeng; Shin, Yongyun
• Is Part Of: Statistics in medicine. Volume 35:Number 26(2016)
• Page Start: 4729
• Page End: 4745
• Publication Date: 2016-07-04
• Subjects: longitudinal data analysis -- multivariate outcomes -- random effects -- missing data -- latent variable -- the EM algorithm; Medical statistics -- Periodicals; Statistique médicale -- Périodiques; Statistiques médicales -- Périodiques; 610.727
• DOI: 10.1002/sim.7022
• Languages: English
• ISSNs: 0277-6715

Abstract

Abstract : In this paper, we analyze a two‐level latent variable model for longitudinal data from the National Growth and Health Study where surrogate outcomes or biomarkers and covariates are subject to missingness at any of the levels. A conventional method for efficient handling of missing data is to re‐express the desired model as a joint distribution of variables, including the biomarkers, that are subject to missingness conditional on all of the covariates that are completely observed, and estimate the joint model by maximum likelihood, which is then transformed to the desired model. The joint model, however, identifies more parameters than desired, in general. We show that the over‐identified joint model produces biased estimation of the latent variable model and describe how to impose constraints on the joint model so that it has a one‐to‐one correspondence with the desired model for unbiased estimation. The constrained joint model handles missing data efficiently under the assumption of ignorable missing data and is estimated by a modified application of the expectation‐maximization algorithm. Copyright © 2016 John Wiley & Sons, Ltd.