Starting treatment at a CD4 count of 350 would be cost-effective in South Africa, with a maximum extra expenditure of $1.5 billion over five years if everyone eligible was treated, according to findings from a collaborative study by American and South African researchers published in the August 4th edition of the Annals of Internal Medicine.
South Africa’s Department of Health is currently considering a recommendation from the South African National AIDS Council (SANAC) to revise national guidelines so that people diagnosed with HIV infection can receive treatment once their CD4 counts fall below 350 cells/mm3. This would bring the South African public sector into line with recommendations in the United States and Europe, and align the public sector with the recommendations of the South African HIV Clinicians Society, which are already followed by most private sector providers.
Earlier treatment has the potential to reduce deaths and illness, but only if people with HIV infection are tested and then initiated on treatment before experiencing a serious CD4 cell decline.
At a symposium during the International AIDS Society conference in Cape Town last month Dr Francois Venter, President of the South African HIV Clinicians Society, warned that South Africa was still failing to initiate treatment promptly in people diagnosed with very low CD4 counts. He said that the health system needed to address this issue urgently, and that current debates about earlier treatment were simply ignoring this question.
In their analysis, Rochelle Walensky and colleagues in the Cost-Effectiveness of Preventing AIDS Complications (CEPAC) International group used a computer-based model of HIV disease progression and 2006 South African health system costs, together with WHO estimates of the number of people infected with HIV, in order to assess the potential increase in treatment costs and gains in life expectancy if treatment guidelines were to recommend earlier HIV treatment for South Africans.
The full methodology of the study can be reviewed in the published journal article, which is freely available online.
Patients in the hypothetical cohort were assumed to have a baseline CD4 count of 375, and their disease course over the next five years was projected, together with the costs of providing care to those who either became eligible for treatment under current South African guidelines, or who required medical care as a result of falling ill due to HIV infection, or who died.
The study assumed that in people who received treatment according to different potential guidelines, 84% would achieve a viral load below 50 copies/ml after 48 weeks, with a mean CD4 cell increase of 184 cells within the same period. Of those who failed first-line treatment, 71% would be assumed to achieve undetectable viral load. These estimates were based on data from South African cohorts already receiving treatment.
They found that over a five-year period 4.7 million people in South Africa would become eligible for treatment if the CD4 count threshold was raised to 350, of whom 1.2 million are already judged to be eligible, with a further 1.6 million becoming eligible within one year. In years three, four and five, another 1.9 million people would become eligible, indicating that the impact of changing the guidelines could be felt very quickly by the health system.
However, not all these patients are likely to be identified. The researchers analysed the impact of three different levels of diagnosis and linkage to care. If 10% of people eligible for treatment under new guidelines actually started treatment the effect on deaths and illness would be modest (just 25,000 fewer deaths over a five-year period), and taking into account the reduced cost of treating opportunistic infections, health spending would rise by $142 million over five years.
If fifty per cent of those eligible were diagnosed and started treatment, around 600,000 deaths would be averted (a one-third reduction), while health spending would rise by a net $1.1 billion over five years.
One hundred per cent success in diagnosing and treating everyone eligible would avert around 1.5 million deaths and lead to additional health expenditure of $1.5 billion over five years, even taking into account the money saved through illness averted.
Current debates over earlier treatment in resource-limited settings also focus on the long-term financial sustainability of treating larger numbers of patients. Cost-effectiveness analysis can also demonstrate how changes in life expectancy and health service utilisation in people who receive treatment translate into long-term costs, and the extent to which the investment is affordable within a country’s own resources.
In the case of South Africa, the CEPAC International analysis shows that earlier treatment would be affordable within the framework endorsed by the World Health Organization for measuring the cost-effectiveness of new health interventions in developing countries. The incremental cost-effectiveness ratio is the ratio of the cost per life year saved by the intervention to GDP per capita. Where the ratio is less than 1, the investment represents very good value for money, and where it is less than 3, the investment is cost-effective.
If starting treatment at a CD4 count of 350 results in a superior outcome to treatment at 250, as a recent trial in Haiti has shown, earlier treatment is highly cost-effective for South Africa, with an incremental cost-effectiveness ratio of $1200 per life year saved compared to starting treatment at a CD4 count of 250 (South African GDP in 2006 was $5400).
However, treatment advocates have criticised current levels of funding in South Africa, and say they are inadequate to meet current needs, let alone expanded demand for treatment.
Walensky RP et al. When to start antiretroviral therapy in resource-limited settings. Ann Int Med 151: 157-166, 2009.