PURPOSE: Heterosexuals (HETs) are the second most affected risk group in terms of annual number of HIV diagnoses after men who have sex with men (MSM), yet few studies have evaluated cost-effective screening frequencies for high-risk HETs. One approach to screening high-risk HETs that has demonstrated effectiveness in identifying high-prevalence areas is targeting low socio-economic status, urban communities. We evaluated the cost and effects of screening high-risk HETs at increasing frequency using such an approach.
METHODS: We applied the HOPE model, a dynamic compartmental model of the HIV epidemic, to examine HIV screening at various frequencies for low- and high-risk HET populations. The model examines HIV progression and transmission in the US population aged 13-64, stratified into 195 subpopulations based on HIV transmission risk, risk level and demographic characteristics. It includes 25 compartments defined by HIV disease and continuum-of-care stages. High-risk HETs were defined as sexually active HETs from US Census tracts that were urban, high-poverty, white-minority areas. Low-risk HETs were all other sexually active HETs. Model outcomes from 2016-2035 included HIV incidence and prevalence, discounted costs and quality-adjusted life years (QALYs), and incremental cost-effectiveness ratios (ICERs). We conducted an elementary effects sensitivity analysis, one-way sensitivity analysis utilizing 20% variation of base case values, and threshold analyses.
RESULTS: When screening the low-risk HET population every 20 years, screening high-risk HETs as frequently as annually was cost-effective with an ICER of $70,600 per QALY gained compared to screening high-risk HETS at 3-year intervals. Screening high-risk HETs every 6 months versus annually yielded an ICER of $129,400 per QALY gained (Table). Only extreme parameter values yielded ICERs that crossed the $100,000 cost-effectiveness threshold for annual screening. Screening every 6 months became cost-effective at the $100,000 threshold if testing was over 80% conventional versus rapid and testing costs decreased 33% from base case values. Screening high-risk HETs reduced projected 20-year cumulative HIV incidence for the population by 4.5% and 5.1% at annual and 6-month intervals, respectively versus screening every 20 years. Our findings were generally robust to 20% variations in key parameters including HIV transmission risks, test sensitivity, probability of viral suppression, and treatment costs.
CONCLUSIONS: Screening high-risk HETS can be cost-effective when conducted annually and could be considered economically attractive at 6-month intervals.
