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 30,800 dollars/QALY (one-time screening), 32,300 dollars/QALY (screening every 5 years), and 55,500 dollars/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 60,700 dollars/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 50,000 dollars/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%.