Cost-effectiveness of HIV treatment as prevention in serodiscordant couples

Abstract

Background: The cost-effectiveness of early antiretroviral therapy (ART) in persons infected with human immunodeficiency virus (HIV) in serodiscordant couples is not known. Using a computer simulation of the progression of HIV infection and data from the HIV Prevention Trials Network 052 study, we projected the cost-effectiveness of early ART for such persons.

Methods: For HIV-infected partners in serodiscordant couples in South Africa and India, we compared the early initiation of ART with delayed ART. Five-year and lifetime outcomes included cumulative HIV transmissions, life-years, costs, and cost-effectiveness. We classified early ART as very cost-effective if its incremental cost-effectiveness ratio was less than the annual per capita gross domestic product (GDP; $8,100 in South Africa and $1,500 in India), as cost-effective if the ratio was less than three times the GDP, and as cost-saving if it resulted in a decrease in total costs and an increase in life-years, as compared with delayed ART.

Results: In South Africa, early ART prevented opportunistic diseases and was cost-saving over a 5-year period; over a lifetime, it was very cost-effective ($590 per life-year saved). In India, early ART was cost-effective ($1,800 per life-year saved) over a 5-year period and very cost-effective ($530 per life-year saved) over a lifetime. In both countries, early ART prevented HIV transmission over short periods, but longer survival attenuated this effect; the main driver of life-years saved was a clinical benefit for treated patients. Early ART remained very cost-effective over a lifetime under most modeled assumptions in the two countries.

Conclusions: In South Africa, early ART was cost-saving over a 5-year period. In both South Africa and India, early ART was projected to be very cost-effective over a lifetime. With individual, public health, and economic benefits, there is a compelling case for early ART for serodiscordant couples in resource-limited settings. (Funded by the National Institute of Allergy and Infectious Diseases and others.).

Figure 1. HIV Transmissions among Serodiscordant Couples in South Africa, According to the Strategy for the Initiation of Antiretroviral Therapy (ART).

Shown are results for a modeled cohort of 1 million HIV-infected index patients in serodiscordant relationships, according to whether they received no ART, delayed ART, or early ART. Panel A shows the total number of transmissions per year, and Panel B shows the cumulative number of transmissions. The number of transmissions includes both first-order and second-order transmissions.

Figure 2. Results of One-Way Sensitivity Analyses.

Shown are the effects of various treatment and transmission variables on the incremental cost-effectiveness ratio (the change in cost divided by the change in life-years) for early ART, as compared with delayed ART, over a 5-year period in South Africa (Panel A) and India (Panel B). ART efficacy was defined as HIV RNA suppression at 48 weeks. In these tornado diagrams (so named because the data are listed vertically in a funnel pattern, with the most important variables at the top), the solid vertical line indicates the incremental cost-effectiveness ratio for the base-case scenario in the study. The length of the horizontal bars indicates the range of incremental cost-effectiveness ratios over the specified range of variable values; the longer the bar, the greater the sensitivity of the incremental cost-effectiveness ratio to that variable. To the right of the horizontal bars in Panel A, the range of values that were examined is shown in parentheses, with the value producing the lower incremental cost-effectiveness ratio listed first. Incremental cost-effectiveness ratios that met the definition of cost-saving (which was defined as both a decrease in total costs and an increase in life-years) are not shown in the tornado diagram. Instead, the cost-saving range for incremental cost-effectiveness ratios is provided to the left of the horizontal bars. The dashed vertical black line indicates the gross domestic product (GDP) of the country (the threshold for being very cost-effective), and the dashed vertical red line represents three times the GDP of the country (the threshold for being cost-effective, which is shown for India only). The GDPs are shown in dollars (see the Methods section). In South Africa, numerous ranges of values that were examined, including all transmission variables, showed that early ART was cost-saving over a 5-year period. In India, early ART, as compared with delayed ART, was found to be cost-effective over a 5-year period for the base case; with variation in some treatment variables, early ART was very cost-effective (<$1,500 per life-year saved). OD denotes opportunistic disease, and PY person-year.