Document 0670
 DOCN  M94A0670
 TI    Length of phases of HIV disease defined by CD4 lymphocyte count.
 DT    9412
 AU    Carlin JB; Clinical Epidemiology & Biostatistics Unit, Royal Children's;
       Hospital, Melbourne.
 SO    Annu Conf Australas Soc HIV Med. 1993 Oct 28-30;5:47 (abstract no. SE3).
       Unique Identifier : AIDSLINE ASHM5/94348985
 AB    OBJECTIVES: To review and synthesize available knowledge on the usual
       lengths of time spent by persons with HIV in each of the clinically
       defined phases: (1) CD4 count > 500 (x 10(6)/l), (2) CD4 count 200-500,
       (3) CD4 count < 200 but no AIDS-defining illness, (4) AIDS. METHODS:
       Extensive literature review performed of all papers reporting relevant
       data or statistical modelling. Estimates of phase length were derived
       from published models both mathematically and using computer
       simulations. RESULTS: Few researchers have studied the natural history
       of HIV disease in a way that allows estimates of the length of phases
       defined by CD4-count, because of the difficulty of performing necessary
       cohort studies and the natural variability of lymphocyte counts. From
       three independent studies, estimates ranging between: (1) 4.1 to 8.2
       years, (2) 3.9 to 5.2 years and (3) 1.6 to 2.6 years were derived for
       the mean duration of the first three phases. Variances are large,
       especially for the first phase. CONCLUSIONS: The summary values obtained
       in this analysis are useful for economic analysis and health services
       planning and may have some limited value for clinical prognosis.
 DE    Acquired Immunodeficiency Syndrome/CLASSIFICATION/DIAGNOSIS/
       *IMMUNOLOGY  Cohort Studies  Computer Simulation  Human  HIV
       Infections/CLASSIFICATION/DIAGNOSIS/*IMMUNOLOGY  *Leukocyte Count
       Models, Statistical  T4 Lymphocytes/*IMMUNOLOGY  MEETING ABSTRACT

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