Biomaterial Database

A semi-parametric regression analysis of CD4 cell counts. 2001

J Sun

Department of Statistics, University of Missouri, 222 Math Sciences Building, Columbia, Missouri 65211, USA. tsun@stat.missouri.edu

This paper considers the regression analysis of CD4 cell counts, a commonly used indicator and prognostic factor of AIDS progression. For this purpose, a number of methods have been proposed and most of them are based on random effects models. We present an alternative that is based on a mean function regression model. The new method is more natural and particularly appropriate if population parameters such as treatment comparison are mainly of interest. To estimate regression parameters, we present an estimating equation-based approach, which does not require estimation of the baseline mean function. This makes the implementation of the approach and the study of the properties of the estimated regression parameters much easier than those based on random effects models. The method is illustrated with a set of CD4 cell count data arising from an AIDS clinical trial and simulated data.

UI	MeSH Term	Description	Entries
D012044	Regression Analysis	Procedures for finding the mathematical function which best describes the relationship between a dependent variable and one or more independent variables. In linear regression (see LINEAR MODELS) the relationship is constrained to be a straight line and LEAST-SQUARES ANALYSIS is used to determine the best fit. In logistic regression (see LOGISTIC MODELS) the dependent variable is qualitative rather than continuously variable and LIKELIHOOD FUNCTIONS are used to find the best relationship. In multiple regression, the dependent variable is considered to depend on more than a single independent variable.	Regression Diagnostics,Statistical Regression,Analysis, Regression,Analyses, Regression,Diagnostics, Regression,Regression Analyses,Regression, Statistical,Regressions, Statistical,Statistical Regressions
D006801	Humans	Members of the species Homo sapiens.	Homo sapiens,Man (Taxonomy),Human,Man, Modern,Modern Man
D000163	Acquired Immunodeficiency Syndrome	An acquired defect of cellular immunity associated with infection by the human immunodeficiency virus (HIV), a CD4-positive T-lymphocyte count under 200 cells/microliter or less than 14% of total lymphocytes, and increased susceptibility to opportunistic infections and malignant neoplasms. Clinical manifestations also include emaciation (wasting) and dementia. These elements reflect criteria for AIDS as defined by the CDC in 1993.	AIDS,Immunodeficiency Syndrome, Acquired,Immunologic Deficiency Syndrome, Acquired,Acquired Immune Deficiency Syndrome,Acquired Immuno-Deficiency Syndrome,Acquired Immuno Deficiency Syndrome,Acquired Immuno-Deficiency Syndromes,Acquired Immunodeficiency Syndromes,Immuno-Deficiency Syndrome, Acquired,Immuno-Deficiency Syndromes, Acquired,Immunodeficiency Syndromes, Acquired,Syndrome, Acquired Immuno-Deficiency,Syndrome, Acquired Immunodeficiency,Syndromes, Acquired Immuno-Deficiency,Syndromes, Acquired Immunodeficiency
D001699	Biometry	The use of statistical and mathematical methods to analyze biological observations and phenomena.	Biometric Analysis,Biometrics,Analyses, Biometric,Analysis, Biometric,Biometric Analyses
D016032	Randomized Controlled Trials as Topic	Works about clinical trials that involve at least one test treatment and one control treatment, concurrent enrollment and follow-up of the test- and control-treated groups, and in which the treatments to be administered are selected by a random process, such as the use of a random-numbers table.	Clinical Trials, Randomized,Controlled Clinical Trials, Randomized,Trials, Randomized Clinical
D018791	CD4 Lymphocyte Count	The number of CD4-POSITIVE T-LYMPHOCYTES per unit volume of BLOOD. Determination requires the use of a fluorescence-activated flow cytometer.	Lymphocyte Count, CD4,T4 Lymphocyte Count,CD4 Cell Counts,CD4 Counts,CD4+ Cell Counts,CD4+ Counts,CD4 Cell Count,CD4 Count,CD4 Lymphocyte Counts,CD4+ Cell Count,CD4+ Count,Count, T4 Lymphocyte,Counts, T4 Lymphocyte,Lymphocyte Count, T4,Lymphocyte Counts, CD4,Lymphocyte Counts, T4,T4 Lymphocyte Counts