title: Impact of Age and Sex on CD4+ Cell Count Trajectories following Treatment Initiation: An Analysis of the Tanzanian HIV Treatment Database.
abstract: OBJECTIVE
  New guidelines recommend that all HIV-infected individuals initiate antiretroviral treatment (ART) immediately following diagnosis. This study describes how immune reconstitution varies by gender and age to help identify poorly reconstituting subgroups and inform targeted testing initiatives.
  
  
  METHODS
  Longitudinal data from the outpatient monitoring system of the National AIDS Control Program in Tanzania.
  
  
  METHODS
  An asymptotic nonlinear mixed effects model was fit to post-treatment CD4+ cell count trajectories, allowing for fixed effects of age and sex, and an age by sex interaction.
  
  
  RESULTS
  Across 220,544 clinic visits from 32,069 HIV-infected patients, age- and sex-specific average CD4+ cell count at ART initiation ranged from 83-136 cells/mm3, long term asymptotic CD4+ cell count ranged from 301-389 cells/mm3, and time to half of maximal CD4+ reconstitution ranged from 3.57-5.68 months. CD4+ cell count at ART initiation and asymptotic CD4+ cell count were 1.28 (95% CI: 1.18-1.40) and 1.25 (95% CI: 1.20-1.31) times higher, respectively, for females compared to males in the youngest age group (19-29 years). Older patients started treatment at higher CD4+ counts but experienced slower CD4+ recovery than younger adults. Treatment initiation at greater CD4+ cell counts was correlated with greater asymptotic CD4+ cell counts within all sex and age groups.
  
  
  CONCLUSIONS
  Older adults should initiate care early in disease progression because total immune reconstitution potential and rate of reconstitution appears to decrease with age. Targeted HIV testing and care linkage remains crucial for patient populations who tend to initiate treatment at lower CD4+ cell counts, including males and younger adults.
authors.affiliation: Department of Global Health, University of Washington, Seattle, Washington, United States of America.
authors.forename: Arianna R
authors.initials: AR
authors.lastname: Means
authors.affiliation: Department of Epidemiology, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland, United States of America.
authors.forename: Kathryn A
authors.initials: KA
authors.lastname: Risher
authors.affiliation: The South African Department of Science and Technology, National Research Foundation Centre of Excellence in Epidemiological Modelling and Analysis (SACEMA), University of Stellenbosch, Stellenbosch, South Africa.
authors.forename: Eva L
authors.initials: EL
authors.lastname: Ujeneza
authors.affiliation: Department of Mathematics and Statistics, School of Health and Applied Sciences, Polytechnic of Namibia, Windhoek, Namibia.
authors.forename: Innocent
authors.initials: I
authors.lastname: Maposa
authors.affiliation: National AIDS Control Program, Ministry of Health and Social Welfare (MOHSW), Dar es Salaam, The United Republic of Tanzania.
authors.forename: Joseph
authors.initials: J
authors.lastname: Nondi
authors.affiliation: Department of Epidemiology and Biostatistics, College of Public Health, University of Georgia, Athens, Georgia, United States of America.
authors.forename: Steven E
authors.initials: SE
authors.lastname: Bellan
mesh_terms: D000328:Adult; D019380:Anti-HIV Agents / Q000627:therapeutic use*; D023241:Antiretroviral Therapy, Highly Active / Q000379:methods; D018791:CD4 Lymphocyte Count / Q000379:methods; D015496:CD4-Positive T-Lymphocytes / Q000187:drug effects*; D018450:Disease Progression; D005260:Female; D015658:HIV Infections / Q000188:drug therapy*; D006801:Humans; D008297:Male; D008875:Middle Aged; D013636:Tanzania; D055815:Young Adult
chemical_list: D019380:Anti-HIV Agents