title: Using HIV-attributable mortality to assess the impact of antiretroviral therapy on adult mortality in rural Tanzania.
abstract: BACKGROUND
  The Tanzanian national HIV care and treatment programme has provided free antiretroviral therapy (ART) to HIV-positive persons since 2004. ART has been available to participants of the Kisesa open cohort study since 2005, but data to 2007 showed a slow uptake of ART and a modest impact on mortality. Additional data from the 2010 HIV serological survey provide an opportunity to update the estimated impact of ART in this setting.
  
  
  METHODS
  The Kisesa Health and Demographic Surveillance Site (HDSS) has collected HIV serological data and demographic data, including verbal autopsy (VA) interviews since 1994. Serological data to the end of 2010 were used to make two estimates of HIV-attributable mortality, the first among HIV positives using the difference in mortality between HIV positives and HIV negatives, and the second in the population using the difference between the observed mortality rate in the whole population and the mortality rate among the HIV negatives. Four time periods (1994-1999, 2000-2004, 2005-2007, and 2008-2010) were used and HIV-attributable mortality estimates were analysed in detail for trends over time. A computer algorithm, InterVA-4, was applied to VA data to estimate the HIV-attributable mortality for the population, and this was compared to the estimates from the serological survey data.
  
  
  RESULTS
  Among HIV-positive adults aged 45-59 years, high mortality rates were observed across all time periods in both males and females. In HIV-positive men, the HIV-attributable mortality was 91.6% (95% confidence interval (CI): 84.6%-95.3%) in 2000-2004 and 86.3% (95% CI: 71.1%-93.3%) in 2008-2010, while among women, the HIV-attributable mortality was 87.8% (95% CI: 71.1%-94.3%) in 2000-2004 and 85.8% (95% CI: 59.6%-94.4%) in 2008-2010. In the whole population, using the serological data, the HIV-attributable mortality among men aged 30-44 years decreased from 57.2% (95% CI: 46.9%-65.3%) in 2000-2004 to 36.5% (95% CI: 18.8%-50.1%) in 2008-2010, while among women the corresponding decrease was from 57.3% (95% CI: 49.7%-63.6%) to 38.7% (95% CI: 27.4%-48.2%). The HIV-attributable mortality in the population using estimates from the InterVA model was lower than that from HIV sero-status data in the period prior to ART, but slightly higher once ART became available.
  
  
  CONCLUSIONS
  In the Kisesa HDSS, ART availability corresponds with a decline in adult overall mortality, although not as large as expected. Using InterVA to estimate HIV-attributable mortality showed smaller changes in HIV-related mortality following ART availability than the serological results.
authors.affiliation: National Institute for Medical Research, Mwanza, Tanzania; London School of Hygiene and Tropical Medicine, London, UK; Chifundo.kanjala@lshtm.ac.uk.
authors.forename: Chifundo
authors.initials: C
authors.lastname: Kanjala
authors.affiliation: National Institute for Medical Research, Mwanza, Tanzania.
authors.forename: Denna
authors.initials: D
authors.lastname: Michael
authors.affiliation: National Institute for Medical Research, Mwanza, Tanzania; London School of Hygiene and Tropical Medicine, London, UK.
authors.forename: Jim
authors.initials: J
authors.lastname: Todd
authors.affiliation: London School of Hygiene and Tropical Medicine, London, UK.
authors.forename: Emma
authors.initials: E
authors.lastname: Slaymaker
authors.affiliation: London School of Hygiene and Tropical Medicine, London, UK.
authors.forename: Clara
authors.initials: C
authors.lastname: Calvert
authors.affiliation: National Institute for Medical Research, Mwanza, Tanzania.
authors.forename: Raphael
authors.initials: R
authors.lastname: Isingo
authors.affiliation: London School of Hygiene and Tropical Medicine, London, UK.
authors.forename: Alison
authors.initials: A
authors.lastname: Wringe
authors.affiliation: London School of Hygiene and Tropical Medicine, London, UK.
authors.forename: Basia
authors.initials: B
authors.lastname: Zaba
authors.affiliation: National Institute for Medical Research, Mwanza, Tanzania.
authors.forename: Mark
authors.initials: M
authors.lastname: Urassa
mesh_terms: D000293:Adolescent; D000328:Adult; D000367:Age Factors; D019380:Anti-HIV Agents / Q000627:therapeutic use*; D005260:Female; D015658:HIV Infections / Q000188:drug therapy / Q000453:epidemiology / Q000401:mortality*; D006801:Humans; D008297:Male; D008875:Middle Aged; D009026:Mortality; D011159:Population Surveillance; D012424:Rural Population / Q000706:statistics & numerical data; D013636:Tanzania / Q000453:epidemiology; D055815:Young Adult
chemical_list: D019380:Anti-HIV Agents
keywords: ART; HDSS; HIV-attributable mortality; InterVA model; serological survey; verbal autopsy