Increased access to antiretroviral therapy has raised adult life expectancy by more than 11 years since 2004 in a community with high HIV prevalence, according to a study published today in the journal ‘Science’. The observed increase in life expectancy - one of the most rapid in the history of public health - confirms that the benefits ofantiretroviral therapy far outweigh the costs of providing treatment and have important implications for government investment decisions in public health programmes.
Researchers at the Wellcome Trust Africa Centre for Health and Population Studies (Africa Centre) followed more than 100 000 people in rural KwaZulu-Natal, South Africa, collecting data on births and deaths to measure adult life expectancy between 2000 and 2011.
The study reveals a dip in adult life expectancy between 2000 and 2003 to just 49 years; however, from 2004 onwards, asantiretroviral therapy (ART) became available through the public sector health system, life expectancy began to rise dramatically, reaching over 60 years in 2011.
When deaths from HIV-related causes were excluded from the analysis, life expectancy remained constant over the observation period at 70 years, suggesting that the improvements in life expectancy overall were due to HIV patients living for longer.
Till Bärnighausen, Senior Epidemiologist at the Africa Centre and Associate Professor of Global Health at Harvard School of Public Health, the senior author of the study, explains: "It's well known that ART significantly improves survival among ART patients, but this is the first study to look at the full population-level impact of a public sector ART program on adult life expectancy.
"We demonstrate that the dramatic observed life expectancy gains in this community in rural KwaZulu-Natal are most likely due to ART, and we did not find any evidence that the ART scale-up has increased mortality unrelated to HIV.
"This latter finding is important: since the start of the large ART scale-up in southern Africa, people have been worried that this massive public health intervention will divert funds and attention from general health services, and so negatively affect populations who do not suffer from HIV but need care for other diseases."
From the late 1980s, the HIV epidemic has led to a huge decline in life expectancy among working-age adults. In addition to the direct loss of life, these declines have a profound negative impact on households, communities and governments, with large increases in the numbers of orphans and the loss of skilled workers such as teachers and doctors.
Previous studies have modelled the future effects and costs of ART for clinical and epidemiological populations. Such predictive models, however, require a range of assumptions about the future development of parameters affecting ART effects and costs, which may not hold in real life.
"In this study, we compare for the first time observed changes in adult survival at the population level with the estimated costs of providing ART in an entire community to empirically establish the cost-effectiveness of the past ART delivery," explains Jacob Bor, a doctoral student at the Harvard School of Public Health and first author of the study.
"It is important to note that we are directly measuring the total population health effects of a real-life public sector ART programme in rural Africa, where retention and adherence are imperfect and levels of treatment failure are high."
An ART investment of $1593 in this community saved one life year. Investments in health interventions that require spending of less than the annual per-capita gross national income to save one year of life are conventionally considered highly cost-effective. South Africa's per capita gross national income in 2011 was $6960.
"This is the clearest evidence yet that well-designed public sector ART programmes are highly effective and worth every penny spent," said Jimmy Whitworth, Head of International Activities at the Wellcome Trust. "The study sends a clear message to governments and donors around the world who are debating levels of support for such programmes."
In 2011, there were 30.7 million people living with HIV infection around the world. The most recent estimates indicate that around 54 per cent of those eligible for ART are currently receiving the treatment.
KwaZulu-Natal is a largely rural community in South Africa. It has a very high rate of HIV prevalence: almost a third of the adult population are infected with the virus, and more than half of women aged 25-29 in this region are living with HIV. In 2010, about one-third of adults living with HIV in the area had initiated ART through the public sector treatment program.