American Statistical Association
New York City
Metropolitan Area Chapter

Mailman School of Public Health
Columbia University
Department of Biostatistics Colloquium



QUANTILE REGRESSION FOR LONGITUDINAL DATA
WITH LEFT CENSORING AND INFORMATIVE DROP-OUTS

by

Lan Kong, Ph.D.
Department of Biostatistics
Graduate School of Public Health
University of Pittsburgh
www.biostat.pitt.edu/directory/bios/kong.asp


Abstract

Biomarkers are often measured repeatedly in biomedical studies to help understand the development of diseases. In the Genetic and Inflammatory Markers of Sepsis (GenIMS) study, many markers on different pathways were measured for patients with community-acquired pneumonia during the course of hospitalization. However, the longitudinal analysis of these markers is complicated by the informative drop-outs due to death or discharge early, and left censoring due to detection limits of the given assays. To account for these two issues, we consider a weighting technique for quantile regression models, which impose minimal assumptions on the distribution of the data. In particular, we weight the estimating equation for censored quantile regression by the inverse probability of drop-out. We evaluate our method through simulation studies and use a GenIMS data set for demonstration.

Biographical Note

Lan Kong is an assistant professor at the Department of Biostatistics, University of Pittsburgh. She obtained her Ph.D. degree in Biostatistics from the University of North Carolina at Chapel Hill. Her research interests focus on survival modeling for time to event data arising from case-cohort studies, risk prediction with multiple markers measured over time and statistical methods for analyzing censored data due to detection limits. She collaborates with investigators at the Department of Critical Care Medicine on studies of acute illness such as sepsis, septic shock and acute kidney injury.


Date: Thursday, March 11, 2010
Time: 4:00 - 5:00 P.M.
Location: Mailman School of Public Health
Department of Biostatistics
722 West 168th Street
Biostatistics Computer Lab
6th Floor - Room 656
New York, New York

RESERVATIONS ARE NOT REQUIRED

Informal tea at 3:40 P.M.


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