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Review
. 2014 Nov;28 Suppl 4(4):S427-34.
doi: 10.1097/QAD.0000000000000483.

Updates to the spectrum model to estimate key HIV indicators for adults and children

John Stover  1 , Kirill Andreev, Emma Slaymaker, Chaitra Gopalappa, Keith Sabin, Claudia Velasquez, Jessica Nakiyingi-Miiro, Amelia Crampin, Tom Lutalo, Kobus Herbst, Simon Gregson, Mark Urassa
Affiliations
Review

Updates to the spectrum model to estimate key HIV indicators for adults and children

John Stover et al. AIDS. 2014 Nov.

Abstract

Background: The Spectrum program is used to estimate key HIV indicators for national programmes. The purpose of the study is to describe the key updates made to Spectrum in the last 2 years to produce the version used in the 2013 global estimates of HIV/AIDS.

Methods: The United Nations Programme on HIV/AIDS (UNAIDS) Reference Group on Estimates, Models and Projections regularly reviews new data and information needs and recommends updates to the methodology and assumptions used in Spectrum. The latest data from surveys, census and special studies are used to estimate key parameter values for countries and regions.

Results: Country-specific life tables prepared by the United National Population Division (UNPD) have been incorporated into Spectrum's demographic projections replacing the model life tables used previously. This update includes revised estimates of non-AIDS life expectancy. Incidence among all adults 15-49 years generated from curve fitting to surveillance and survey data is now split by age using incidence rate ratios derived from Analysing Longitudinal Population-based HIV/AIDS data on Africa Network data for generalized epidemics. Methods for estimating the number of AIDS orphans have been updated to include the changing effects of PMTCT and antiretroviral therapy programmes. Procedures for estimating the number of adults eligible for treatment have been updated to reflect the 2013 WHO guidelines. Program data on AIDS mortality has been used to estimate prevalence trends in Argentina, Brazil and Mexico for the 2013 estimates.

Conclusion: Spectrum was updated for the 2013 round of HIV estimates in order to support national programmes with improved methods and data to estimating national indicators.

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Figures

Fig. 1
Fig. 1
Mortality in Malawi with and without AIDS.
Fig. 2
Fig. 2
Percentage of HIV+ adults in serodiscordant stable partnerships versus adult HIV prevalence.
Fig. 3
Fig. 3
Incidence rate ratios by sex, age, and time period.
Fig. 4
Fig. 4
Schematic representation of surviving orphans born during different time periods of mother's life based on HIV-status of mother at time of death.
Fig. 5
Fig. 5
Incidence trends in Mexico derived from fitting to surveillance data on prevalence by risk group and by fitting to program data on AIDS deaths, people living with HIV and new cases identified.
See this image and copyright information in PMC

References

    1. Stover J, Brown T, Marston M. Updates to the Spectrum/Estimation and Projection Package (EPP) model to estimate HIV trends for adults and children (2012). Sex Trans Infect 2012; 88:i11–ii16doi:10.1136/sextrans-2012-050640. - PMC - PubMed
    1. United Nations, Department of Economic and Social Affairs, Population Division (2013). World Population Prospects: The 2012 Revision, Volume I: Comprehensive Tables.
    1. Todd J, Glynn J, Marston M, Lutalo T, Biraro S, Mwita W, et al. Time from HIV seroconversion to death: a collaborative analysis of eight studies in six low and middle income countries before highly active antiretroviral therapy. AIDS 2007; 21 Suppl 6:S55–S63. - PMC - PubMed
    1. Marston M, Todd J, Glynn JR, Nelson KE, Rangsin R, Lutalo T, et al. Estimating ‘net’ HIV-related mortality and the importance of background mortality rates. AIDS 2007; 21 Suppl 6:S65–S71. - PMC - PubMed
    1. Yiannoutsos CT, Johnson LF, Boulle A, Musick BS, Gsponer E, Balestre E, et al. Estimated mortality of adult HIV-infected patients starting treatment with combination antiretroviral therapy. Sex Transm Infect 2012; 88:i33–i43doi:10.1136/sextrans-2012-050658. - PMC - PubMed

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