L-1 COMPARATIVE EFFECTIVENESS AND COST-EFFECTIVENESS OF ANTIRETROVIRAL THERAPY AND PRE-EXPOSURE PROPHYLAXIS FOR HIV PREVENTION IN SOUTH AFRICA

Friday, October 19, 2012: 4:00 PM
Regency Ballroom D (Hyatt Regency)
Health Services, and Policy Research (HSP)
Candidate for the Lee B. Lusted Student Prize Competition

Sabina S. Alistar, MS, Philip M. Grant, MD and Eran Bendavid, MD, MS, Stanford University, Stanford, CA

Purpose: Recent evidence shows both antiretroviral therapy (ART) and oral pre-exposure prophylaxis (PrEP) are effective in reducing HIV transmission in heterosexual adults in resource-limited settings. The epidemiologic impact and cost-effectiveness of combined prevention approaches remain unclear.

Method: We develop a dynamic mathematical model of the adult South African HIV epidemic. We consider 3 disease stages: early (CD4 > 350 cells/µL), late (200-350 cells/µL) and advanced (< 200 cells/µL). Infectiousness is based on disease stage, number of sexual partnerships, ART, and PrEP. We assume ART reduces HIV transmission by 95% and PrEP by 60%.  We model 2 ART strategies: scaling up access for those with CD4 counts ≤ 350 cells/µL (Guidelines) and for all identified HIV-infected individuals (Universal).  PrEP strategies include use in the general population (General) and in high-risk individuals (Focused). We consider strategies where ART, PrEP, or both are scaled up to recruit 25%, 50%, 75% or 100% of remaining eligible individuals yearly. We assume annual costs of $150 for ART and $80 for PrEP. We measure infections averted, quality-adjusted life-years (QALY) gained and incremental cost-effectiveness ratios over 20 years.

Result: Scaling up ART to 50% of eligible individuals in South Africa averts 1,513,000 infections over 20 years using the Guidelines and 3,591,000 infections using a Universal strategy. Universal ART is more cost-effective than Guidelines ($310-$340/QALY gained compared with status quo). Expanding Guidelines ART to recruit 50% of those eligible yearly costs $410/QALY gained versus status quo, and this estimate is stable with higher coverage rates. General PrEP is costly and provides relatively small benefits beyond those of ART scale-up. Cost-effectiveness of General PrEP becomes less favorable when ART is given more widely ($1,050-$2,800/QALY gained). However, Focused PrEP is cost saving compared with the status quo and when added to any ART strategies except 75% or 100% Universal, where it is highly cost-effective.

Conclusion: Expanded ART coverage to individuals in early disease stages is more cost-effective than expansion of treatment per current guidelines. PrEP can be cost-saving if it can be delivered to individuals at increased risk of infection.