BACKGROUND: Two key strategies for reducing HIV incidence in the United States are 1) delivering pre-exposure prophylaxis (PrEP) to persons at high risk of acquiring HIV, and 2) preventing HIV transmission through enhanced diagnosis, care, and treatment of persons living with HIV (PLWH). The efficacy of PrEP for reducing HIV transmission among men who have sex with men (MSM), persons who inject drugs (PWID), and high-risk heterosexuals (HRH) has been well established. The targets for the second strategy, derived from US national goals, include increasing from the current care continuum the proportion of PLWH that are diagnosed to 90%, the proportion of newly diagnosed PLWH that are linked to care to 85%, and the proportion of diagnosed PLWH with viral suppression to 80%. We investigate the marginal cost-effectiveness of PrEP compared with improving the HIV care continuum.
METHODS: We used the HIV Optimization and Prevention Economics (HOPE) compartmental model that simulates the sexually active population in the United States. Our model includes the cost of care and treatment, PrEP costs, and the transition cost of moving from one step of the HIV continuum to another. We set PrEP coverage for 2016 (40% for MSM, 10% for PWID and HRH), allowed it to change until 2020 according to aging, death, and HIV infection, and then assumed it was zero from 2021 onward. We assumed there was no other dropout from PrEP between 2016 and 2020. We assessed cumulative costs, incidence, and quality-adjusted-life-years (QALYs) from 2016 through 2060. We first estimated the cost-effectiveness of delivering PrEP under the current care continuum. We then repeated the analysis for the scenario when national goals were achieved. Finally, we estimated the cost-effectiveness of improving HIV diagnosis, care, and treatment levels to achieve the national goals. We investigated the marginal cost-effectiveness for the entire population as well as for individual transmission groups.
RESULTS: The overall incremental cost-effectiveness ratio (ICER) of PrEP under current care continuum rates was $1.2 million per QALY gained. MSM benefitted the most from PrEP with an ICER of $636,868 per QALY gained. These ICERs were higher when national goals were achieved ($2.5 million per QALY gained for the total population, and $1.4 million per QALY gained for MSM). Our analysis showed that achieving national goals was cost saving compared to maintaining the current care continuum.
CONCLUSIONS/IMPLICATIONS: Improving the HIV care continuum leads to a large reduction in HIV incidence and is cost-saving because the additional cost of becoming virally suppressed and maintaining viral suppression is outweighed by the costs saved on care, treatment, and other programs. Although administering PrEP is not cost-effective by most cost-effective thresholds, the associated ICERs increase as the HIV care continuum is enhanced. The ICER for delivering PrEP to MSM under the current care continuum is the lowest among all categories and is comparable in magnitude to results reported by other studies of MSM.
