title: Survival after HIV infection in the pre-antiretroviral therapy era in a rural Tanzanian cohort.
abstract: BACKGROUND
  Survival patterns after HIV infection in African populations in the era before antiretroviral therapy (ART) form an important baseline for measuring future successes of treatment programmes. Few studies have followed seroconverters for 10 or more years to describe such patterns.
  
  
  METHODS
  The Kisesa open cohort study conducted four rounds of village-based HIV testing and 20 rounds of household-based demographic surveillance between 1994 and 2006. Approximate infection dates were established for individual seroconverters by allocating a date between the last negative and first positive test. Person-years lived post-infection were computed, allowing for left truncation and right censoring, and Kaplan-Meier survival functions were constructed, truncating the analysis at the start of 2005 when ART first became available in the community. Weibull models were fitted to estimate median survival time, and parametric regression methods were used to investigate the influence of sex and age at infection.
  
  
  RESULTS
  A total of 369 seroconverters were identified, providing 890 person-years of follow-up during which 44 deaths were observed. The Kaplan-Meier function showed 67% surviving 9 years post-infection, and the overall predicted median survival was 11.5 years. Survival was strongly related to age at infection (hazard ratio 1.06 for each additional year of age, and weakly to sex. A strong effect of age was evident even after allowing for mortality from non-HIV-related causes using cause deletion methods to estimate net mortality.
  
  
  CONCLUSIONS
  The survival of HIV-infected individuals was comparable to that reported in developed country studies before the introduction of HAART. Survival patterns in Kisesa are marginally more favourable than those reported in cohort studies in Uganda.
authors.affiliation: National Institute for Medical Research, Mwanza, Tanzania. rrisingo@yahoo.co.uk
authors.forename: Raphael
authors.initials: R
authors.lastname: Isingo
authors.forename: Basia
authors.initials: B
authors.lastname: Zaba
authors.forename: Milly
authors.initials: M
authors.lastname: Marston
authors.forename: Milalu
authors.initials: M
authors.lastname: Ndege
authors.forename: Julius
authors.initials: J
authors.lastname: Mngara
authors.forename: Wambura
authors.initials: W
authors.lastname: Mwita
authors.forename: Alison
authors.initials: A
authors.lastname: Wringe
authors.forename: David
authors.initials: D
authors.lastname: Beckles
authors.forename: John
authors.initials: J
authors.lastname: Changalucha
authors.forename: Mark
authors.initials: M
authors.lastname: Urassa
mesh_terms: D000328:Adult; D000367:Age Factors; D015331:Cohort Studies; D018450:Disease Progression; D005260:Female; D015658:HIV Infections / Q000188:drug therapy / Q000401:mortality*; D006679:HIV Seropositivity; D006801:Humans; D008297:Male; D012423:Rural Health; D016019:Survival Analysis; D015996:Survival Rate / Q000639:trends; D013636:Tanzania / Q000453:epidemiology