A Semi-nonparametric Approach to Joint Modeling of A Primary Binary Outcome and Longitudinal Data Measured at Discrete Informative Times

Bibliographic Details
Authors and Corporations: Yan, Song
Title: A Semi-nonparametric Approach to Joint Modeling of A Primary Binary Outcome and Longitudinal Data Measured at Discrete Informative Times
In: Statistics in Biosciences, 4, 2012, 2, p. 213-234
published:
Springer-Verlag
Physical Description:213-234
ISSN/ISBN: 1867-1772
1867-1764
EISSN:1867-1772
Summary:In a study conducted at the New York University Fertility Center, one of the scientific objectives is to investigate the relationship between the final pregnancy outcomes of participants receiving an in vitro fertilization (IVF) treatment and their <Emphasis Type="Italic">β</Emphasis>-human chorionic gonadotrophin (<Emphasis Type="Italic">β</Emphasis>-hCG) profiles. A common joint modeling approach to this objective is to use subject-specific normal random effects in a linear mixed model for longitudinal <Emphasis Type="Italic">β</Emphasis>-hCG data as predictors in a model (e.g., logistic model) for the final pregnancy outcome. Empirical data exploration indicates that the observation times for longitudinal <Emphasis Type="Italic">β</Emphasis>-hCG data may be informative and the distribution of random effects for longitudinal <Emphasis Type="Italic">β</Emphasis>-hCG data may not be normally distributed. We propose to introduce a third model in the joint model for the informative <Emphasis Type="Italic">β</Emphasis>-hCG observation times, and relax the normality distributional assumption of random effects using the semi-nonparametric (SNP) approach of Gallant and Nychka (Econometrica 55:363–390, 1987). An EM algorithm is developed for parameter estimation. Extensive simulation designed to evaluate the proposed method indicates that ignoring either informative observation times or distributional assumption of the random effects would lead to invalid and/or inefficient inference. Applying our new approach to the data reveals some interesting findings the traditional approach failed to discover.
Type of Resource:E-Article
Source:Springer Journals
sid-105-col-springerjournals
Language: English