Censored linear regression models for irregularly observed longitudinal data using the multivariate-t distribution
Authors:
- Aldo M. Gary,
- Luis M. Castro,
- Jacek Leskow,
- Victor H. Lachos
Abstract
In acquired immunodeficiency syndrome (AIDS) studies it is quite common to observe viral load measurements collected irregularly over time. Moreover, these measurements can be subjected to some upper and/or lower detection limits depending on the quantification assays.Acomplication arises when these continuous repeated measures have a heavy-tailed behavior. For such data structures, we propose a robust structure for a censored linear model based on the multivariate Student’s t-distribution. To compensate for the autocorrelation existing among irregularly observed measures, a damped exponential correlation structure is employed. An efficient expectation maximization type algorithm is developed for computing the maximum likelihood estimates, obtaining as a by-product the standard errors of the fixed effects and the log-likelihood function. The proposed algorithm uses closed-form expressions at the E-step that rely on formulas for the mean and variance of a truncated multivariate Student’s t-distribution. The methodology is illustrated through an application to an Human Immunodeficiency Virus-AIDS (HIV-AIDS) study and several simulation studies.
- Record ID
- CUTeebcf381275d4d6590b41676e88a7a44
- Publication categories
- ;
- Author
- Journal series
- Statistical Methods in Medical Research, ISSN 0962-2802, e-ISSN 1477-0334
- Issue year
- 2017
- Vol
- 26
- No
- 2
- Pages
- 542-566
- Other elements of collation
- tab.; wykr.; Bibliografia (na s.) - 565-566; Bibliografia (liczba pozycji) - 41; Oznaczenie streszczenia - Abstr.; Data udostępnienia on-line - 2014-10-08; Numeracja w czasopiśmie - Vol. 26., Iss. 2
- Keywords in English
- censored data, expectation conditional maximization algorithm, longitudinal data, HIV viral load, outliers
- DOI
- DOI:10.1177/0962280214551191 Opening in a new tab
- URL
- http://smm.sagepub.com/content/early/2014/10/07/0962280214551191.abstract Opening in a new tab
- Language
- eng (en) English
- Score (nominal)
- 45
- Additional fields
- Indeksowana w: Web of Science, Scopus
- Uniform Resource Identifier
- https://cris.pk.edu.pl/info/article/CUTeebcf381275d4d6590b41676e88a7a44/
- URN
urn:pkr-prod:CUTeebcf381275d4d6590b41676e88a7a44
* presented citation count is obtained through Internet information analysis, and it is close to the number calculated by the Publish or PerishOpening in a new tab system.