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Statistical Modeling of Longitudinal Data with Non-ignorable Non-monotone Missingness with Semiparametric Bayesian
Yu Cao1, Nitai D Mukhopadhyay1
1Department of Biostatistics, Virginia Commonwealth University, 830 East Main Street, Richmond, VA.
This study introduces a novel statistical approach using latent class analysis and pattern-mixture models to handle missing outcome data in longitudinal studies, improving accuracy for small sample sizes.
Area of Science:
- Statistics
- Biostatistics
- Longitudinal Data Analysis
Background:
- Longitudinal studies involve repeated measurements over time.
- Missing outcome data is common due to lost follow-up or missed visits.
- Non-ignorable missingness assumes missingness relates to unobserved data.
Purpose of the Study:
- To extend pattern-mixture models (PMM) for longitudinal data with non-ignorable, non-monotone missingness.
- To develop a method accommodating small sample sizes.
- To improve imputation accuracy for missing outcomes.
Main Methods:
- Utilized latent class analysis (LCA) to group similar missingness patterns.
- Employed a shared-parameter PMM allowing class-specific parameters.
- Proposed imputation using observed data conditioned on latent classes.
Main Results:
- The proposed method demonstrated improved performance in simulation studies.
- Achieved a smaller mean squared error compared to existing methods.
- Successfully applied to a Phase II clinical trial dataset.
Conclusions:
- The novel LCA-based PMM approach effectively handles complex missing data in longitudinal studies.
- The method offers a valuable tool for analyzing data with small sample sizes.
- Enhances the analysis of quality of life data in prostate cancer clinical trials.
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