Latent time-varying factors in longitudinal analysis: a linear mixed hidden Markov model for heart rates
Longitudinal data are often segmented by unobserved time‐varying factors, which introduce latent heterogeneity at the observation level, in addition to heterogeneity across subjects. We account for this latent structure by a linear mixed hidden Markov model. It integrates subject‐specific random eff...
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Published in | Statistics in medicine Vol. 33; no. 23; pp. 4116 - 4134 |
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Main Authors | , , |
Format | Journal Article |
Language | English |
Published |
England
Blackwell Publishing Ltd
15.10.2014
Wiley Subscription Services, Inc |
Subjects | |
Online Access | Get full text |
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Summary: | Longitudinal data are often segmented by unobserved time‐varying factors, which introduce latent heterogeneity at the observation level, in addition to heterogeneity across subjects. We account for this latent structure by a linear mixed hidden Markov model. It integrates subject‐specific random effects and Markovian sequences of time‐varying effects in the linear predictor. We propose an expectationŰ‐maximization algorithm for maximum likelihood estimation, based on data augmentation. It reduces to the iterative maximization of the expected value of a complete likelihood function, derived from an augmented dataset with case weights, alternated with weights updating. In a case study of the Survey on Stress Aging and Health in Russia, the model is exploited to estimate the influence of the observed covariates under unobserved time‐varying factors, which affect the cardiovascular activity of each subject during the observation period. Copyright © 2014 John Wiley & Sons, Ltd. |
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Bibliography: | Supporting info item istex:2E8BA812841344039377FECB67249EABB54A6F8B ArticleID:SIM6220 ark:/67375/WNG-KJTVFLC3-N SourceType-Scholarly Journals-1 ObjectType-Feature-1 content type line 14 ObjectType-Article-1 ObjectType-Feature-2 content type line 23 lagona@uniroma3.it |
ISSN: | 0277-6715 1097-0258 1097-0258 |
DOI: | 10.1002/sim.6220 |