Analyzing Incomplete Discrete Longitudinal Clinical Trial Data
Reads0
Chats0
TLDR
An overview of the various modeling frameworks for non-Gaussian longitudinal data is provided, and a focus on generalized linear mixed-effects models, on the one hand, of which the parameters can be estimated using full likelihood, and on generalized estimating equations, which is a nonlikelihood method and hence requires a modification to be valid under MAR.Abstract:
Commonly used methods to analyze incomplete longitudi- nal clinical trial data include complete case analysis (CC) and last observation carried forward (LOCF). However, such methods rest on strong assumptions, including missing completely at random (MCAR) for CC and unchanging profile after dropout for LOCF. Such assump- tions are too strong to generally hold. Over the last decades, a number of full longitudinal data analysis methods have become available, such as the linear mixed model for Gaussian outcomes, that are valid un- der the much weaker missing at random (MAR) assumption. Such a method is useful, even if the scientific question is in terms of a sin- gle time point, for example, the last planned measurement occasion, and it is generally consistent with the intention-to-treat principle. The validity of such a method rests on the use of maximum likelihood, un- der which the missing data mechanism is ignorable as soon as it is MAR. In this paper, we will focus on non-Gaussian outcomes, such as binary, categorical or count data. This setting is less straightforward since there is no unambiguous counterpart to the linear mixed model. We first provide an overview of the various modeling frameworks for non-Gaussian longitudinal data, and subsequently focus on generalized linear mixed-effects models, on the one hand, of which the parameters can be estimated using full likelihood, and on generalized estimating equations, on the other hand, which is a nonlikelihood method and hence requires a modification to be valid under MAR. We briefly com- ment on the position of models that assume missingness not at random and argue they are most useful to perform sensitivity analysis. Our developments are underscored using data from two studies. While the case studies feature binary outcomes, the methodology applies equally well to other discrete-data settings, hence the qualifier "discrete" in the title.read more
Citations
More filters
Journal ArticleDOI
Multiple Imputation for Nonresponse in Surveys
TL;DR: It is concluded that multiple Imputation for Nonresponse in Surveys should be considered as a legitimate method for answering the question of why people do not respond to survey questions.
반도체 공정 overview
TL;DR: The study of distributed systems which bring to life the vision of ubiquitous computing systems, also known as ambient intelligence, is concentrated on in this work.
Journal ArticleDOI
The Prevention and Treatment of Missing Data in Clinical Trials
Roderick J. A. Little,Ralph B. D'Agostino,Michael L. Cohen,Kay Dickersin,Scott S. Emerson,John T. Farrar,Constantine Frangakis,Joseph W. Hogan,Geert Molenberghs,Susan A. Murphy,James D. Neaton,Andrea Rotnitzky,Daniel O. Scharfstein,Weichung Joe Shih,Jay P. Siegel,Hal S. Stern +15 more
TL;DR: Methods for preventing missing data and, failing that, dealing with data that are missing in clinical trials are reviewed.
Journal ArticleDOI
Much ado about nothing: A comparison of missing data methods and software to fit incomplete data regression models.
Nicholas J. Horton,Ken Kleinman +1 more
TL;DR: These routines to incorporate observations with incomplete variables in regression models are reviewed in the context of a motivating example from a large health services research dataset, and it is feasible to incorporate partially observed values.
References
More filters
Book
Generalized Linear Models
Peter McCullagh,John A. Nelder +1 more
TL;DR: In this paper, a generalization of the analysis of variance is given for these models using log- likelihoods, illustrated by examples relating to four distributions; the Normal, Binomial (probit analysis, etc.), Poisson (contingency tables), and gamma (variance components).
Book
Statistical Analysis with Missing Data
TL;DR: This work states that maximum Likelihood for General Patterns of Missing Data: Introduction and Theory with Ignorable Nonresponse and large-Sample Inference Based on Maximum Likelihood Estimates is likely to be high.
Journal ArticleDOI
Longitudinal data analysis using generalized linear models
Kung Yee Liang,Scott L. Zeger +1 more
TL;DR: In this article, an extension of generalized linear models to the analysis of longitudinal data is proposed, which gives consistent estimates of the regression parameters and of their variance under mild assumptions about the time dependence.
Book
Multiple imputation for nonresponse in surveys
TL;DR: In this article, a survey of drinking behavior among men of retirement age was conducted and the results showed that the majority of the participants reported that they did not receive any benefits from the Social Security Administration.
Journal ArticleDOI
Categorical Data Analysis
TL;DR: In this article, categorical data analysis was used for categorical classification of categorical categorical datasets.Categorical Data Analysis, categorical Data analysis, CDA, CPDA, CDSA