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Abstract Details
Activity Number:
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664
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Type:
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Contributed
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Date/Time:
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Thursday, August 2, 2012 : 10:30 AM to 12:20 PM
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Sponsor:
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Section on Bayesian Statistical Science
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Abstract - #304381 |
Title:
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Segmental Modeling of Viral Load Changes for HIV Longitudinal Data with Skewness and Detection Limits
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Author(s):
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Yangxin Huang*+
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Companies:
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University of South Florida
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Address:
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Department of Epidemiology and Biostat, Tampa, FL, 33612-3805, United States
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Keywords:
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Bayesian analysis ;
Change-points ;
Left-censoring ;
HIV/AIDS ;
Segmental mixed-effects models ;
Skew distributions
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Abstract:
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Although it is a common practice to analyze complex HIV longitudinal data using NLME models in literature, the following issues may standout: (i) In clinical practice, the profile of each subject's viral response may follow a ``broken stick" like trajectory, indicating multiple phases of decline and increase in response. Such multiple phases may be an important indicator to help quantify treatment effect. To estimate change-points, NLME models become a challenge. (ii) The commonly-assumed distribution for model errors is normal, but this assumption may unrealistically obscure important features of subject variations. (iii) The response observations may be subject to left-censoring due to a limit of detection. Inferential procedures can be complicated dramatically when data with asymmetric characteristics and left-censoring are observed in conjunction with change-points as unknown parameters into models. There is relatively little work concerning all these features simultaneously. This article proposes Bayesian segmental mixed-effects models with skew distributions for the response process (with left-censoring). A real data example is used to illustrate the proposed methods.
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Authors who are presenting talks have a * after their name.
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