Using economic threshold analysis to determine the intensity of HIV prevention services for HIV-seropositive persons

Studies of the effectiveness of HIV prevention interventions for persons living with HIV have examined interventions with very wide variation in intensity (from single session interventions to those offered twice-weekly for 6 months); this raises questions about cost-effectiveness. Herein the question is asked: at varied (but specified) levels of HIV transmission rates and intervention effectiveness, how much money can be spent per HIV-seropositive client on HIV prevention services and still be considered cost-saving to society (in the United States)?

Standard methods of economic evaluation (threshold analysis, in particular) were used. Per-client HIV transmission rates and intervention effectiveness were specified and then allowed to vary widely. The threshold for intervention cost (as well as number of sessions per client) that could be justified on the basis of societal cost savings was then calculated.

If HIV transmissions are permanently prevented and lifetime medical costs are avoided in an HIV-seronegative partner, then monthly counseling sessions, even after high quality pre- and post-test counseling, and even at moderate levels of effectiveness, may be cost-saving to society (and at higher transmission rates and effectiveness, dozens of sessions per client could be cost-saving). If these interventions delay (but do not permanently prevent) HIV infection among HIV-seronegative partners, then the cost and number of session thresholds are substantially lower.

Even with considerable uncertainty in input parameters, an economic evaluation threshold analysis framework can yield useful insights for guiding the selection of intensity of HIV prevention services for persons living with HIV.