Scaling up antiretroviral therapy in South Africa: the impact of speed on survival

Abstract

Background: Only 33% of eligible human immunodeficiency virus (HIV)-infected patients in South Africa receive antiretroviral therapy (ART). We sought to estimate the impact of alternative ART scale-up scenarios on patient outcomes from 2007-2012.

Methods: Using a simulation model of HIV infection with South African data, we projected HIV-associated mortality with and without effective ART for an adult cohort in need of therapy (2007) and for adults who became eligible for treatment (2008-2012). We compared 5 scale-up scenarios: (1) zero growth, with a total of 100,000 new treatment slots; (2) constant growth, with 600,000; (3) moderate growth, with 2.1 million; (4) rapid growth, with 2.4 million); and (5) full capacity, with 3.2 million.

Results: Our projections showed that by 2011, the rapid growth scenario fully met the South African need for ART; by 2012, the moderate scenario met 97% of the need, but the zero and constant growth scenarios met only 28% and 52% of the need, respectively. The latter scenarios resulted in 364,000 and 831,000 people alive and on ART in 2012. From 2007 to 2012, cumulative deaths in South Africa ranged from 2.5 million under the zero growth scenario to 1.2 million under the rapid growth scenario.

Conclusions: Alternative ART scale-up scenarios in South Africa will lead to differences in the death rate that amount to more than 1.2 million deaths by 2012. More rapid scale-up remains critically important.

Figure 1

No. of patients alive and on antiretroviral therapy (ART) at the end of each year, according to scale-up scenario (dashed and dotted lines), compared with previously published South African projections (solid lines). The constant growth scenario modeled in the study best approximates the projections of the Actuarial Society of South Africa (ASSA), whereas the moderate growth scenario best approximates the projections of the South African Joint Task Team on HIV Care in the Public Sector [6, 28, 31].

Figure 2

Percentage of patients eligible and alive who received antiretroviral therapy, for each modeled scenario. The rapid-growth scenario met 100% of need by 2011, and the moderate-growth scenario met 97% of need by 2012. The constant-growth scenario remained relatively unchanged and met 52% of need by 2012. The percentage of need met in the zero-growth scenario declined steadily to 28% in 2012.

Figure 3

Annual projected no. of deaths through 2012, stratified by scale-up scenario and year. All scale-up scenarios (except full capacity) involved the same number of treatment slots in 2007, and all scenarios included the availability of 2 successive lines of therapy. The estimated number of deaths each year for those awaiting antiretroviral therapy (ART) and those receiving ART were calculated for each scale-up scenario by use of mortality rates generated from model output. Annual mortality rates for both the prevalent and incident cohorts were stratified by treatment status (awaiting ART or receiving ART) and length of time awaiting therapy.

Figure A1

Percentage of total patients eligible for antiretroviral therapy (ART) (both those awaiting and those receiving ART) who were alive by year, for each modeled scenario. The cumulative total of all eligible patients is noted below the graph, by year. The changing denominator and rapid increase in access to ART account for the change in slope of the moderate-growth and rapid-growth curves. Nonprioritized cases are indicated with open symbols, and prioritized cases are indicated with solid symbols.