Document 1256
 DOCN  M9591256
 TI    Modelling progression of CD4-lymphocyte count and its relationship to
       survival time.
 DT    9509
 AU    De Gruttola V; Tu XM; Department of Biostatistics, Harvard School of
       Public Health,; Boston, Massachusetts 02115.
 SO    Biometrics. 1994 Dec;50(4):1003-14. Unique Identifier : AIDSLINE
       MED/95306580
 AB    The purpose of this article is to model the progression of
       CD4-lymphocyte count and the relationship between different features of
       this progression and survival time. The complicating factors in this
       analysis are that the CD4-lymphocyte count is observed only at certain
       fixed times and with a high degree of measurement error, and that the
       length of the vector of observations is determined, in part, by the
       length of survival. If probability of death depends on the true,
       unobserved CD4-lymphocyte count, then the survival process must be
       modelled. Wu and Carroll (1988, Biometrics 44, 175-188) proposed a
       random effects model for two-sample longitudinal data in the presence of
       informative censoring, in which the individual effects included only
       slopes and intercepts. We propose methods for fitting a broad class of
       models of this type, in which both the repeated CD4-lymphocyte counts
       and the survival time are modelled using random effects. These methods
       permit us to estimate parameters describing the progression of
       CD4-lymphocyte count as well as the effect of differences in the CD4
       trajectory on survival. We apply these methods to results of AIDS
       clinical trials.
 DE    Acquired Immunodeficiency Syndrome/DRUG THERAPY/*IMMUNOLOGY/  *MORTALITY
       Biometry/METHODS  Comparative Study  *CD4 Lymphocyte Count  Disease
       Progression  Human  Mathematics  *Models, Statistical  Probability
       Randomized Controlled Trials  Support, U.S. Gov't, P.H.S.  *Survival
       Rate  Time Factors  Zidovudine/*THERAPEUTIC USE  JOURNAL ARTICLE

       SOURCE: National Library of Medicine.  NOTICE: This material may be
       protected by Copyright Law (Title 17, U.S.Code).