Modelling human immunodeficiency virus ribonucleic acid levels with finite mixtures for censored longitudinal data
The measurement of human immunodeficiency virus ribonucleic acid levels over time leads to censored longitudinal data. Suitable models for dynamic modelling of these levels need to take this data characteristic into account. If groups of patients with different developments of the levels over tim...
| Main Authors: | , |
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| Format: | Others |
| Language: | en |
| Published: |
Wiley
2012
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| Subjects: | |
| Online Access: | http://epub.wu.ac.at/3708/1/j.1467%2D9876.2011.01007.x.pdf |
| Summary: | The measurement of human immunodeficiency virus ribonucleic acid levels over time
leads to censored longitudinal data. Suitable models for dynamic modelling of these levels need
to take this data characteristic into account. If groups of patients with different developments of
the levels over time are suspected the model class of finite mixtures of mixed effects models
with censored data is required.We describe the model specification and derive the estimation
with a suitable expectation-maximization algorithm.We propose a convenient implementation
using closed form formulae for the expected mean and variance of the truncated multivariate
distribution. Only efficient evaluation of the cumulative multivariate normal distribution function
is required. Model selection as well as methods for inference are discussed. The application is
demonstrated on the clinical trial ACTG 315 data. |
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