The Epidemiologic and Economic Impact of Improving HIV Testing, Linkage, and Retention in Care in the United States

Abstract

Background: Recent guidelines advocate early antiretroviral therapy (ART) to decrease human immunodeficiency virus (HIV) morbidity and prevent transmission, but suboptimal engagement in care may compromise impact. We sought to determine the economic and epidemiologic impact of incomplete engagement in HIV care in the United States.

Methods: We constructed a dynamic transmission model of HIV among US adults (aged 15-65 years) and conducted a cost-effectiveness analysis of improvements along the HIV care continuum : We evaluated enhanced HIV testing (annual for high-risk groups), increased 3-month linkage to care (to 90%), and improved retention (50% relative reduction in yearly disengagement and 50% increase in reengagement). Our primary outcomes were HIV incidence, mortality, costs and quality-adjusted life-years (QALYs).

Results: Despite early ART initiation, a projected 1.39 million (95% uncertainty range [UR], 0.91-2.2 million) new HIV infections will occur at a (discounted) cost of $256 billion ($199-298 billion) over 2 decades at existing levels of HIV care engagement. Enhanced testing with increased linkage has modest epidemiologic benefits and could reduce incident HIV infections by 21% (95% UR, 13%-26%) at a cost of $65 700 per QALY gained ($44 500-111 000). By contrast, comprehensive improvements that couples enhanced testing and linkage with improved retention would reduce HIV incidence by 54% (95% UR, 37%-68%) and mortality rate by 64% (46%-78%), at a cost-effectiveness ratio of $45 300 per QALY gained ($27 800-72 300).

Conclusions: Failure to improve engagement in HIV care in the United States leads to excess infections, treatment costs, and deaths. Interventions that improve not just HIV screening but also retention in care are needed to optimize epidemiologic impact and cost-effectiveness.

Keywords: HIV; cost-effectiveness; economics; mathematical model.

Figure 1.

Model schematic of human immunodeficiency virus (HIV) transmission, disease progression, and engagement in HIV care. The population is divided into compartments based on HIV status (and stage of HIV for HIV-infected), and engagement with HIV care. HIV⁺ represents HIV-infected individuals; HIV⁻, HIV-uninfected individuals. Each compartment is stratified further by sex and risk group (heterosexual, men who have sex with men, persons who inject drugs). The model incorporates transmission through sex and injection drug use. *Persons living with HIV (at any point in the HIV continuum of care) progress through a series of HIV stages from acute HIV to AIDS if not receiving antiretroviral therapy (ART), shown in subset. Individuals experience immunologic recovery if receiving ART and virally suppressed. CD4 represents CD4 cell count (in cells per microliter).

Figure 2.

Impact of interventions to improve human immunodeficiency virus (HIV) screening and engagement in care. Shown are the model projections of total numbers (boldface) and percentage reductions (in parentheses) of new HIV infections (blue) and AIDS deaths (red) during the next 20 years, after implementation of 5 different interventions (95% UR). Intervention A includes yearly screening of young heterosexuals, all men who have sex with men, and all persons who inject drugs; intervention B, general population screening every 3 years, coupled with intervention A; intervention C, an intervention that results in 90% of newly diagnosed individuals achieving linkage to care within 3 months, coupled with intervention A (targeted screening); intervention D, an intervention that reduces the annual rate of disengagement by 50%, and increases the rate of reengagement in care by 50%; and intervention E, a comprehensive package of interventions that includes interventions C (targeted screening plus improved linkage to care) and D (improved retention in care). All scenarios (including current standard of care) assume antiretroviral eligibility at all CD4 cell counts. Abbreviation: UR, uncertainty range.

Figure 3.

Sensitivity analysis of key parameters comparing current levels of engagement in care with comprehensive enhancements in human immunodeficiency virus (HIV) continuum of care (targeted yearly screening of high-risk groups, improved linkage to care, and improved yearly retention). A, Incremental cost-effectiveness ratio (ICER) comparing a comprehensive intervention to improve HIV continuum of care with current HIV care. B, Incident HIV cases averted comparing a comprehensive intervention to improve HIV continuum of care with current HIV care. Solid vertical line represents base-case values (ie, base-case ICER [$45 300 per QALY gained] in A, and base-case incremental HIV cases averted [n = 752 000] in B); blue bars, low values of parameter range; red bars, high values of parameter range. Abbreviations: ART, antiretroviral therapy; CD4, CD4 cell count (in cells per microliter); IDU, injection drug use; MSM, men who have sex with men; PWID, persons who inject drugs; QALY, quality-adjusted life-year.