Study finds antiretroviral therapy cost-effective in South African setting

Contrary to expectations about the expense of antiretroviral therapy (ART), using ART in people with AIDS should be cost-effective for South Africa’s public health sector according to a study published in January’s PLoS Medicine (an 'open-access' medical journal). The cost of not using ART to treat people with AIDS is significantly greater — as patients with AIDS required more expensive time in the hospital and other medical care.

In less ill patients with HIV, the study also found that using ART was still less expensive than medical care without ART, but only if lower cost generic drugs rather than brand name drugs are used.

Cost-effectiveness studies

In industrialised countries, like the United Kingdom and the United States, studies in the late 1990s demonstrated that ART was very cost-effective. ART led to dramatic improvements in health and a shift from inpatient hospital care to outpatient clinic visits. In addition, patients on ART underwent fewer diagnostic procedures and needed fewer costly treatments for opportunistic infections. Finally, ART in industrialised countries extended life, and added years of productivity for people with HIV who were able to get back to work again or continue working.

Until recently, there seemed to be little point in conducting similar studies in the developing world, but in the past few years, dramatic reductions in the cost of antiretroviral drugs has allowed the rollout of ART through the public health sector of several resource-constrained countries, including South Africa.

South Africa’s health system was already under severe stress from the impacts of the HIV epidemic. By the year 2000, HIV-related conditions accounted for nearly one fourth of all public hospital admissions and one eighth of the total public health budget, and the problem is only expected to worsen. Given the scale of the epidemic in the country, the fate of South Africa’s health care system is dependant upon how efficiently the government manages the crisis.

The trial

A team from the University of Cape Town (collaborating with researchers from Chelsea and Westminster Hospital in London and McGill University in Montreal) conducted a study to calculate the cost of HIV care for persons receiving ART and a comparison group not receiving ART in order to determine the cost-effectiveness of ART in the South African setting. The analysis also compared clinical outcomes, in terms of disease progression and how many years of life were gained (LYG) by the clinical stage of HIV infection (with AIDS: WHO stage 4, and without AIDS: WHO stages 1, 2, and 3).

Subjects were drawn from the Cape Town AIDS Cohort (CTAC), a prospective cohort study that accrued patients before ART was freely available in public sector hospitals (between 1995 and December 2000). All of those receiving ART in the study (292 patients: 265 without-AIDS and 27 with AIDS) were actually participating in phase III clinical trials. These were compared to a group of patients from the CTAC — matched for baseline WHO stage, CD4 count, age, and socio-economic status — who received care for HIV but who were not fortunate enough to receive ART. Hospital records were used to compare outcomes (the number of clinic outpatient visits, days spent in the hospital, lab tests and other costs).

The HIV care costs were based on public sector costs in the year 2000 (adjusted for inflation in 2004), using an exchange rate of 7.6 Rand to the US dollar. For the cost of antiretroviral therapy, they used two figures: Scenario 1) the actual cost of branded drugs to the public sector in 2004, $730 per year, and Scenario 2) the cost for generic ART that was expected to be negotiated by the South African government, $181 per year. (This was indeed close to the cost that was negotiated, at least for the first line nevirapine-based regimen).

Results for people without AIDS

Patients without AIDS on ART spent a mean 1.08 (95% CI: 0.97–1.19) days in the hospital PPY versus 3.73 (95% CI: 3.55–3.97) for the No-ART group, and 8.71 (95% CI: 8.40–9.03) versus 4.35 (95% CI: 4.12–5.61), respectively, for mean number of outpatient visits PPY. Average service provision PPY was $950 for the No-ART group versus $1,342 and $793 PPY for the ART group for scenario 1 and 2, respectively, whereas the incremental cost per life-year gained (LYG) was $1,622 for scenario 1 and $675 for scenario 2.

Results for people with AIDS

Patients with AIDS on ART spent a mean of 2.04 (95% CI: 1.63–2.52) days in the hospital per patient year (PPY) compared to 15.36 (95% CI: 13.97–16.85) days for the group not on ART. Patients on ART were more likely to utilise outpatient services: mean outpatient visits PPY was 7.62 (95% CI: 6.81–8.49) compared to 6.60 (95% CI: 5.69–7.62) for those not on ART.

The average cost PPY of providing services to people with AIDS not on ART was $3,520 versus $1,513 for scenario 1 and $964 for scenario 2 for people with AIDS on ART. The incremental cost per LYG was cost-saving for both scenarios.

Limitations and commentary

Current South African guidelines recommend treatment for people with HIV with symptomatic disease and CD4 cell counts below 200. Because the study used clinical definitions for AIDS (WHO stage 4) but not CD4 cell counts, about a third of the patients not considered to have AIDS would have qualified for treatment in South Africa today. It is unfortunate that a separate analysis did divide the two groups into 'those who would qualify for treatment' today and 'those who would not.' The study noted that, indeed, CD4 cell counts were predictive of progression (and hospitalisation) in a univariate analysis so presumably the cost savings from ART would apply to this group as well. However, the other two thirds of the group without AIDS would not be considered to be in immediate need of treatment — and using ART in such patients may not be cost-effective.

The costs in the study included were only direct costs and did not add in the indirect or intangible costs, such as loss of productivity or quality of life associated with HIV/AIDS. In the UK, such indirect costs can comprise between 45% and 124% of total treatment costs. "Currently no such data exist in South Africa,' the authors note, however, "if these costs were all included, it is likely that the cost-effectiveness ratio would even be more favourable."

The researchers also had to deal with measuring a moving target, conducting their analysis at a time when antiretroviral prices and purchasing policy were in a state of flux. Also today’s Rand is somewhat stronger (at around 6 Rand to the US Dollar), and it's not clear how this would affect the price of antiretroviral drugs or cost of care for people with HIV in this study. Nevertheless, even though the actual prices are somewhat different, the most common first-line regimen is generic and its cost is similar to what the researchers projected. However, the most common second-line regimen, which is anchored by the brand name protease inhibitor Kaletra, is roughly three times as costly.

After years of inaction, the South African government finally began to provide ART though the public sector about a year and a half ago (and negotiated the antiretroviral drug purchasing contracts about a year later). Yet the pace of the rollout is much slower than hoped.

The study illustrates that delay in the rollout of ART (and failure to negotiate better drug prices) doesn’t just hurt people (which ought be enough), it can also be quite expensive. And perhaps that might motivate the government to expedite the process.