title: Duration from seroconversion to eligibility for antiretroviral therapy and from ART eligibility to death in adult HIV-infected patients from low and middle-income countries: collaborative analysis of prospective studies.
abstract: BACKGROUND
  Estimation of the number of people in need of antiretroviral therapy (ART) in resource-limited settings requires information on the time from seroconversion to ART eligibility and from ART eligibility to death.
  
  
  OBJECTIVE
  To estimate duration from seroconversion to different ART eligibility criteria and from ART eligibility to death in HIV-infected adults in low-income and middle-income countries.
  
  
  METHODS
  Participants with documented seroconversion from five cohorts (two cohorts from Uganda, two from Thailand and one from Côte d'Ivoire) were analysed. We used Weibull survival models and Bayesian simulation methods to model true (unobserved) first time of treatment eligibility. We set a consistency constraint so that the mean duration from seroconversion to death was equal to the mean from seroconversion to ART eligibility plus the mean from eligibility to death.
  
  
  RESULTS
  We analysed data from 2072 participants, 16 157 person-years of follow-up and 794 deaths. For the criterion CD4 T-lymphocyte count <200 cells x10(6)/l, the median duration from seroconversion to ART eligibility was 6.1 years (95% credibility interval 3.3-10.4) for all studies and 7.6 years (95% credibility interval 3.4-15.2) for all but the Thai cohorts. Corresponding estimates for the time from CD4 T-lymphocyte count <200 cells x10(6)/l to death were 2.1 years (0.7-4.8) and 2.7 years (0.8-8.4). When including all cohorts, the mean time from serconversion to CD4 T-lymphocyte count <200 cells x10(6)/l and from CD4 T-lymphocyte count <200 cells x10(6)/l to death represented 66% (38-87%) and 34% (13-62%), respectively of the total survival time.
  
  
  CONCLUSIONS
  The duration of different ART eligibility criteria to death was longer than the estimates used in previous calculations of the number of people needing ART. However, uncertainty in estimates was considerable and heterogeneity across cohorts important.
authors.affiliation: Institute of Social and Preventive Medicine (ISPM), University of Bern, Finkenhubelweg 11, CH-3012 Bern, Switzerland.
authors.forename: Simon
authors.initials: S
authors.lastname: Wandel
authors.forename: Matthias
authors.initials: M
authors.lastname: Egger
authors.forename: Ram
authors.initials: R
authors.lastname: Rangsin
authors.forename: Kenrad E
authors.initials: KE
authors.lastname: Nelson
authors.forename: Caroline
authors.initials: C
authors.lastname: Costello
authors.forename: Charlotte
authors.initials: C
authors.lastname: Lewden
authors.forename: Tom
authors.initials: T
authors.lastname: Lutalo
authors.forename: Anthony
authors.initials: A
authors.lastname: Ndyanabo
authors.forename: Jim
authors.initials: J
authors.lastname: Todd
authors.forename: Lieve
authors.initials: L
authors.lastname: Van der Paal
authors.forename: Albert
authors.initials: A
authors.lastname: Minga
authors.forename: Marcel
authors.initials: M
authors.lastname: Zwahlen
mesh_terms: D000328:Adult; D023241:Antiretroviral Therapy, Highly Active / Q000401:mortality / Q000706:statistics & numerical data*; D018791:CD4 Lymphocyte Count / Q000706:statistics & numerical data; D015496:CD4-Positive T-Lymphocytes / Q000473:pathology; D007560:Cote d'Ivoire / Q000453:epidemiology; D003906:Developing Countries / Q000706:statistics & numerical data*; D018450:Disease Progression; D004608:Eligibility Determination; D004812:Epidemiologic Methods; D005260:Female; D006679:HIV Seropositivity / Q000188:drug therapy* / Q000401:mortality / Q000473:pathology; D006801:Humans; D008297:Male; D020380:Needs Assessment; D012959:Socioeconomic Factors; D013785:Thailand / Q000453:epidemiology; D014454:Uganda / Q000453:epidemiology