Expanded HIV testing in low-prevalence, high-income countries: a cost-effectiveness analysis for the United Kingdom

Abstract

Objective: In many high-income countries with low HIV prevalence, significant numbers of persons living with HIV (PLHIV) remain undiagnosed. Identification of PLHIV via HIV testing offers timely access to lifesaving antiretroviral therapy (ART) and decreases HIV transmission. We estimated the effectiveness and cost-effectiveness of HIV testing in the United Kingdom (UK), where 25% of PLHIV are estimated to be undiagnosed.

Design: We developed a dynamic compartmental model to analyze strategies to expand HIV testing and treatment in the UK, with particular focus on men who have sex with men (MSM), people who inject drugs (PWID), and individuals from HIV-endemic countries.

Methods: We estimated HIV prevalence, incidence, quality-adjusted life years (QALYs), and health care costs over 10 years, and cost-effectiveness.

Results: Annual HIV testing of all adults could avert 5% of new infections, even with no behavior change following HIV diagnosis because of earlier ART initiation, or up to 18% if risky behavior is halved. This strategy costs £67,000-£106,000/QALY gained. Providing annual testing only to MSM, PWID, and people from HIV-endemic countries, and one-time testing for all other adults, prevents 4-15% of infections, requires one-fourth as many tests to diagnose each PLHIV, and costs £17,500/QALY gained. Augmenting this program with increased ART access could add 145,000 QALYs to the population over 10 years, at £26,800/QALY gained.

Conclusions: Annual HIV testing of key populations in the UK is very cost-effective. Additional one-time testing of all other adults could identify the majority of undiagnosed PLHIV. These findings are potentially relevant to other low-prevalence, high-income countries.

Figure 1. Projected annual HIV incidence over time in the UK under different testing strategies.

The six graphs correspond to six different risk groups in the UK, with projected annual HIV incidence per 100,000 people shown under current testing and treatment levels (black solid line), universal annual testing of all adults (blue dashed), or universal annual testing coupled with antiretroviral therapy (ART) initiation of 75% at CD4 <350 cells/mm³ (red dotted). The cumulative number of new HIV infections over 10 years is given in Table 3.

Figure 2. Projected total new HIV infections in the UK (2013–2022) under different HIV testing and treatment strategies.

Each bar corresponds to modeled estimates of new HIV infections over the next 10 years, assuming a 25% reduction in sexual partnerships following HIV diagnosis. For each strategy, the higher estimate (top of black line) corresponds to the scenario with no partnership reduction, and the lower estimate (bottom of black line) corresponds to a 50% partnership reduction following diagnosis. The time in parentheses corresponds to the testing interval, and “once” refers to one-time testing of individuals not in the key populations we considered. “ART (75%)” refers to 75% antiretroviral therapy initiation of at CD4 <350 cells/mm³.

Figure 3. Cost-effectiveness of alternative HIV testing and treatment strategies in the UK.

The incremental costs (x-axis) and QALYs (y-axis) of different HIV testing and treatment scenarios are shown, relative to status quo levels. The blue points correspond to universal HIV testing strategies for all adults, with testing every one, two, or three years. The green points correspond to targeted strategies, with annual testing for high-risk persons and testing every two years or one-time for all other persons. The red points correspond to an expanded HIV testing program coupled with 75% antiretroviral therapy initiation of at CD4 <350 cells/mm³. The solid black line marks the cost-effectiveness frontier, or the set of strategies that is most economically efficient, and the corresponding incremental cost-effectiveness ratios are given. Costs and QALYs are discounted at 3% annually, and include the direct costs of the programs over 10 years, as well as the lifetime costs and QALYs of all individuals in the population. HR = high-risk, and includes men who have sex with men (MSM), people who inject drugs (PWID), and men and women from HIV-endemic countries. LR = low-risk, and includes men and women who do not belong to the identified key populations. ART = antiretroviral therapy. QALY = quality-adjusted life year.