Expanded HIV screening in the United States: Effect on clinical outcomes, HIV transmission, and costs

Background: An extensive literature supports expanded HIV screening in the United States. However, the question of whom to test and how frequently remains controversial. Objective: To inform the design of HIV screening programs by identifying combinations of screening frequency and HIV prevalence and incidence at which screening is cost-effective. Design: Cost-effectiveness analysis linking simulation models of HIV screening to published reports of HIV transmission risk, with and without antiretroviral therapy. Data Sources: Published randomized trials, observational cohorts, national cost and service utilization surveys, the Red Book, and previous modeling results. Target Population: U.S. communities with low to moderate HIV prevalence (0.05% to 1.0%) and annual incidence (0.0084% to 0.12%). Time Horizon: Lifetime. Perspective: Societal. Interventions: One-time and increasingly frequent voluntary HIV screening of all adults using a same-day rapid test. Outcome Measures: HIV infections detected, secondary transmissions averted, quality-adjusted survival, lifetime medical costs, and societal cost-effectiveness, reported in discounted 2004 dollars per quality-adjusted life-year (QALY) gained. Results of Base-Case Analysis: Under moderately favorable assumptions regarding the effect of HIV patient care on secondary transmission, routine HIV screening in a population with HIV prevalence of 1.0% and annual incidence of 0.12% had incremental cost-effectiveness ratios of $30800/QALY (one-time screening), $32300/QALY (screening every 5 years), and $55500/QALY (screening every 3 years). In settings with HIV prevalence of 0.10% and annual incidence of 0.014%, one-time screening produced cost-effectiveness ratios of $60700/QALY. Results of Sensitivity Analysis: The cost-effectiveness of screening policies varied within a narrow range as assumptions about the effect of screening on secondary transmission varied from favorable to unfavorable. Assuming moderately favorable effects of antiretroviral therapy on transmission, cost-effectiveness ratios remained below $50000/QALY in settings with HIV prevalence as low as 0.20% for routine HIV screening on a one-time basis and at prevalences as low as 0.45% and annual incidences as low as 0.0075% for screening every 5 years. Limitations: This analysis does not address the difficulty of determining the prevalence and incidence of undetected HIV infection in a given patient population. Conclusions: Routine, rapid HIV testing is recommended for all adults except in settings where there is evidence that the prevalence of undiagnosed HIV infection is below 0.2%.