The cost-effectiveness and population outcomes of expanded HIV screening and antiretroviral treatment in the United States

Abstract

Background: Although recent guidelines call for expanded routine screening for HIV, resources for antiretroviral therapy (ART) are limited, and all eligible persons are not currently receiving treatment.

Objective: To evaluate the effects on the U.S. HIV epidemic of expanded ART, HIV screening, or interventions to reduce risk behavior.

Design: Dynamic mathematical model of HIV transmission and disease progression and cost-effectiveness analysis.

Data sources: Published literature.

Target population: High-risk (injection drug users and men who have sex with men) and low-risk persons aged 15 to 64 years in the United States.

Time horizon: Twenty years and lifetime (costs and quality-adjusted life-years [QALYs]).

Perspective: Societal.

Intervention: Expanded HIV screening and counseling, treatment with ART, or both.

Outcome measures: New HIV infections, discounted costs and QALYs, and incremental cost-effectiveness ratios.

Results of base-case analysis: One-time HIV screening of low-risk persons coupled with annual screening of high-risk persons could prevent 6.7% of a projected 1.23 million new infections and cost $22,382 per QALY gained, assuming a 20% reduction in sexual activity after screening. Expanding ART utilization to 75% of eligible persons prevents 10.3% of infections and costs $20,300 per QALY gained. A combination strategy prevents 17.3% of infections and costs $21,580 per QALY gained.

Results of sensitivity analysis: With no reduction in sexual activity, expanded screening prevents 3.7% of infections. Earlier ART initiation when a CD4 count is greater than 0.350 × 10(9) cells/L prevents 20% to 28% of infections. Additional efforts to halve high-risk behavior could reduce infections by 65%.

Limitation: The model of disease progression and treatment was simplified, and acute HIV screening was excluded.

Conclusion: Expanding HIV screening and treatment simultaneously offers the greatest health benefit and is cost-effective. However, even substantial expansion of HIV screening and treatment programs is not sufficient to markedly reduce the U.S. HIV epidemic without substantial reductions in risk behavior.

Primary funding source: National Institute on Drug Abuse, National Institutes of Health, and Department of Veterans Affairs.

Figure 1. Complementary Effects of Expanded HIV Screening and Treatment

The horizontal axis displays varying levels of HIV screening (current levels, every three years, every two years, or annually), and the vertical axis displays antiretroviral therapy (ART) utilization levels (50%, 60%, 70%, 80%, or 90% utilization). The curves are iso-contours showing a given number (and fraction) of HIV infections prevented over 20 years, compared to the status quo. The point at the origin corresponds to current screening and treatment levels. Assumes HIV screening reduces sexual behavior by 20% among HIV+ identified individuals, and treatment with ART reduces sexual infectivity by 90%. Under the status quo, an estimated 1.23 million HIV infections occur over 20 years.

Figure 2. Cost-Effectiveness of Alternative Screening and Treatment Strategies

Incremental costs and quality-adjusted life years (QALYs) of expanded HIV screening and counseling, expanded access to antiretroviral therapy (ART), or a combination of screening and ART. Expanded screening occurs once, annually, or every three years. Expanded ART includes treatment utilization of 75%. The cost-effectiveness frontier (solid line) includes strategies that may be cost-effective if the incremental cost-effectiveness ratio (ICER) is less than the accepted threshold. Strategies that are not on the frontier are dominated, meaning that these are not an efficient use of resources. Costs and QALYs are calculated over a 20-year time horizon and are discounted to the present.

Figure 3. Fraction of HIV Infections Prevented with Varying HIV Screening Effectiveness

Each bar corresponds to the fraction of HIV infections prevented over 20 years, with varying degrees of screening effectiveness at reducing sexual partners among HIV+ identified individuals (base case: 20%). The benefits from earlier ART are due to infected individuals who are identified through a screening program and can initiate treatment, thereby reducing their infectivity. The benefits from reduced behavior result from reduced sexual partnerships among HIV+ identified individuals – and hence reduced HIV transmission – following screening and counseling. Expanded screening occurs once for low-risk individuals and annually for high-risk individuals. Expanded ART includes treatment utilization of 75%. Under the status quo, an estimated 1.23 million HIV infections occur over 20 years.