title: Assessing and adjusting for differences between HIV prevalence estimates derived from national population-based surveys and antenatal care surveillance, with applications for Spectrum 2013.
abstract: OBJECTIVE
  To assess differences between HIV prevalence estimates derived from national population surveys and antenatal care (ANC) surveillance sites and to improve the calibration of ANC-derived estimates in Spectrum 2013 to more appropriately account for differences between these data.
  
  
  METHODS
  Retrospective analysis of national population survey and ANC surveillance data from 25 countries with generalized epidemics in sub-Saharan Africa and 8 countries with concentrated epidemics.
  
  
  METHODS
  Adult national population survey and ANC surveillance HIV prevalence estimates were compared for all available national population survey data points for the years 1999-2012. For sub-Saharan Africa, a mixed-effects linear regression model determined whether the relationship between national population and ANC estimates was constant across surveys. A new calibration method was developed to incorporate national population survey data directly into the likelihood for HIV prevalence in countries with generalized epidemics. Results were used to develop default rules for adjusting ANC data for countries with no national population surveys.
  
  
  RESULTS
  ANC surveillance data typically overestimate population prevalence, although a wide variation, particularly in rural areas, is observed across countries and survey years. The new calibration method yields similar point estimates to previous approaches, but leads to an average 44% increase in the width of 95% uncertainty intervals.
  
  
  CONCLUSIONS
  Important biases remain in ANC surveillance data for HIV prevalence. The new approach to model-fitting in Spectrum 2013 more appropriately accounts for this bias when producing national estimates in countries with generalized epidemics. In countries with concentrated epidemics, local sex ratios should be used to calibrate ANC surveillance estimates.
authors.affiliation: aUNAIDS, Geneva, Switzerland bDepartment of Global Health and Population, Harvard University, Boston, Massachusetts, USA cDepartment of Health Statistics and Information Systems, World Health Organization, Geneva, Switzerland.
authors.forename: Kimberly
authors.initials: K
authors.lastname: Marsh
authors.forename: Mary
authors.initials: M
authors.lastname: Mahy
authors.forename: Joshua A
authors.initials: JA
authors.lastname: Salomon
authors.forename: Daniel R
authors.initials: DR
authors.lastname: Hogan
mesh_terms: D000293:Adolescent; D000328:Adult; D017954:Africa South of the Sahara / Q000453:epidemiology; D062665:Epidemiological Monitoring; D005260:Female; D015658:HIV Infections / Q000175:diagnosis* / Q000453:epidemiology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D011295:Prenatal Care / Q000379:methods*; D011296:Prenatal Diagnosis / Q000379:methods*; D015995:Prevalence; D012189:Retrospective Studies; D055815:Young Adult