While previous studies have shown that ART significantly improves survival in clinical cohorts of HIV patients receiving ART, this is the first study to directly measure the full population-level impact of a public-sector ART program on adult life expectancy.
"This is one of the most rapid life expectancy gains observed in the history of public health" said Till Bärnighausen, associate professor of global health in the HSPH Department of Global Health and Population and senior author of the study, which was published online in Science
on February 21, 2013.
"The public-sector scale-up of ART has largely reversed the decline in adult life expectancy due to HIV that occurred in the 1990s and early 2000s in the region," said Jacob Bor, the lead author of the study and an HSPH doctoral candidate in the Department of Global Health and Population.
The researchers measured dates of death using data from a large community-based population surveillance system that included information on all births and deaths among more than 100,000 people living in rural KwaZulu-Natal, in South Africa, between 2000 and 2011. Data were collected twice a year, through household surveys, by the Africa Centre for Health and Population Studies at the University of KwaZulu-Natal.
In 2003, the year before ART became widely available to people in KwaZulu-Natal, adult life expectancy was 49.2 years; by 2011, it had increased to 60.5 years. Both men and women experienced large gains in life expectancy—9 years and 13.3 years, respectively. Using cause of death data, the researchers calculated life expectancy among people dying of causes other than HIV. They found that the observed life expectancy gains were almost exclusively due to changes in HIV-related mortality, with no changes in mortality rates from other causes.
"Many people have been worried that the ART scale-up, which is a massive public health intervention, would negatively affect populations who do not suffer from HIV but need care for other diseases. We do not find any evidence to support this worry," said Bor.
Previous studies have attempted to predict the effects and costs of ART programs. Such predictive models, however, require many assumptions about ART effects and costs, which may not hold in reality. This study compared observed changes in adult survival at the population level with the costs of providing ART in this community between 2004 and 2011 to empirically establish the cost-effectiveness of past ART delivery. The ART cost-effectiveness ratio was $1593 per life year saved, that is, less than a quarter of South Africa's 2011 per-capita gross national income (GNI) needed to be invested in the ART scale-up to save one life year.
"Interventions that cost less than per-capita GNI per life year saved are usually considered highly cost-effective," said Bärnighausen. "We find that a real-life public-sector ART program in rural Africa is a very worthwhile investment, despite the fact that treatment failures rates in this program are high because of problems with retention and medication adherence. This information is important for governments and donors debating future investments for ART programs."
Bärnighausen was co-author on another study, also published online in Science
on February 21, 2013, that provides the first empirical evidence that the risk of acquiring HIV among HIV-uninfected individuals in a typical rural population with high HIV prevalence in southern Africa declines significantly with ART coverage in their surrounding communities. For this study, researchers used data from one of Africa's largest population-based HIV surveillance systems to follow up with almost 17,000 individuals who were HIV-uninfected at baseline, to observe individual HIV infections from 2004 to 2011.