Using health surveillance systems data to assess the impact of AIDS and antiretroviral treatment on adult morbidity and mortality in Botswana.

Introduction: Botswana's AIDS response included free antiretroviral treatment (ART) since 2002, achieving 80% coverage of persons with CD4<350 cells/µl by 2009-10. We explored impact on mortality and HIV prevalence, analyzing surveillance and civil registration data.

Methods: Hospital natural cause admissions and deaths from the Health Statistics Unit (HSU) over 1990-2009, all-cause deaths from Midnight Bed Census (MNC) over 1990-2011, institutional and non-institutional deaths recorded in the Registry of Birth and Deaths (RBD) over 2003-2010, and antenatal sentinel surveillance (ANC) over 1992-2011 were compared to numbers of persons receiving ART. Mortality was adjusted for differential coverage and completeness of institutional and non-institutional deaths, and compared to WHO and UNAIDS Spectrum projections.

Results: HSU deaths per 1000 admissions declined 49% in adults 15-64 years over 2003-2009. RBD mortality declined 44% (807 to 452/100,000 population in adults 15-64 years) over 2003-2010, similarly in males and females. Generally, death rates were higher in males; declines were greater and earlier in younger adults, and in females. In contrast, death rates in adults 65+, particularly females increased over 2003-2006. MNC all-age post-neonatal mortality declined 46% and 63% in primary and secondary level hospitals, over 2003-2011. We estimated RBD captured 80% of adult deaths over 2006-2011. Comparing empirical, completeness-adjusted deaths to Spectrum estimates, declines over 2003-2009 were similar overall (47% vs. 54%); however, Spectrum projected larger and earlier declines particularly in women. Following stabilization and modest decreases over 1998-2002, HIV prevalence in pregnant women 15-24 and 25-29-years declined by >50% and >30% through 2011, while continuing to increase in older women.

Conclusions: Adult mortality in Botswana fell markedly as ART coverage increased. HIV prevalence declines may reflect ART-associated reductions in sexual transmission. Triangulation of surveillance system data offers a reasonable approach to evaluate impact of HIV/AIDS interventions, complementing cohort approaches that monitor individual-level health outcomes.