title: InterVA-4 as a public health tool for measuring HIV/AIDS mortality: a validation study from five African countries.
abstract: BACKGROUND
  Reliable population-based data on HIV infection and AIDS mortality in sub-Saharan Africa are scanty, even though that is the region where most of the world's AIDS deaths occur. There is therefore a great need for reliable and valid public health tools for assessing AIDS mortality.
  
  
  OBJECTIVE
  The aim of this article is to validate the InterVA-4 verbal autopsy (VA) interpretative model within African populations where HIV sero-status is recorded on a prospective basis, and examine the distribution of cause-specific mortality among HIV-positive and HIV-negative people.
  
  
  METHODS
  Data from six sites of the Alpha Network, including HIV sero-status and VA interviews, were pooled. VA data according to the 2012 WHO format were extracted, and processed using the InterVA-4 model into likely causes of death. The model was blinded to the sero-status data. Cases with known pre-mortem HIV infection status were used to determine the specificity with which InterVA-4 could attribute HIV/AIDS as a cause of death. Cause-specific mortality fractions by HIV infection status were calculated, and a person-time model was built to analyse adjusted cause-specific mortality rate ratios.
  
  
  RESULTS
  The InterVA-4 model identified HIV/AIDS-related deaths with a specificity of 90.1% (95% CI 88.7-91.4%). Overall sensitivity could not be calculated, because HIV-positive people die from a range of causes. In a person-time model including 1,739 deaths in 1,161,688 HIV-negative person-years observed and 2,890 deaths in 75,110 HIV-positive person-years observed, the mortality ratio HIV-positive:negative was 29.0 (95% CI 27.1-31.0), after adjustment for age, sex, and study site. Cause-specific HIV-positive:negative mortality ratios for acute respiratory infections, HIV/AIDS-related deaths, meningitis, tuberculosis, and malnutrition were higher than the all-cause ratio; all causes had HIV-positive:negative mortality ratios significantly higher than unity.
  
  
  CONCLUSIONS
  These results were generally consistent with relatively small post-mortem and hospital-based diagnosis studies in the literature. The high specificity in cause of death attribution achieved in relation to HIV status, and large differences between specific causes by HIV status, show that InterVA-4 is an effective and valid tool for assessing HIV-related mortality.
authors.affiliation: WHO Collaborating Centre for Verbal Autopsy, Umeå Centre for Global Health Research, Umeå University, Umeå, Sweden; School of Public Health, University of the Witwatersrand, Johannesburg, South Africa; INDEPTH Network, Accra, Ghana; peter.byass@epiph.umu.se.
authors.forename: Peter
authors.initials: P
authors.lastname: Byass
authors.forename: Clara
authors.initials: C
authors.lastname: Calvert
authors.forename: Jessica
authors.initials: J
authors.lastname: Miiro-Nakiyingi
authors.forename: Tom
authors.initials: T
authors.lastname: Lutalo
authors.forename: Denna
authors.initials: D
authors.lastname: Michael
authors.forename: Amelia
authors.initials: A
authors.lastname: Crampin
authors.forename: Simon
authors.initials: S
authors.lastname: Gregson
authors.forename: Albert
authors.initials: A
authors.lastname: Takaruza
authors.forename: Laura
authors.initials: L
authors.lastname: Robertson
authors.forename: Kobus
authors.initials: K
authors.lastname: Herbst
authors.forename: Jim
authors.initials: J
authors.lastname: Todd
authors.forename: Basia
authors.initials: B
authors.lastname: Zaba
mesh_terms: D000293:Adolescent; D000328:Adult; D017954:Africa South of the Sahara / Q000453:epidemiology; D000368:Aged; D001344:Autopsy / Q000379:methods; D002423:Cause of Death; D005260:Female; D015658:HIV Infections / Q000401:mortality*; D006801:Humans; D008297:Male; D008875:Middle Aged; D011634:Public Health / Q000379:methods / Q000706:statistics & numerical data; D055815:Young Adult
keywords: Africa; Alpha Network; HIV/AIDS; InterVA; mortality; verbal autopsy