National HIV Prevention Conference Atlanta, Georgia, USA — July 27 - 30, 2003

Natl HIV Prev Conf 2003 July 27-30:abstract no. M1-E0601
Tuli K, Sansom SL, the INSPIRE Team
Centers for Disease Control, Atlanta, GA

BACKGROUND/OBJECTIVES:: This study describes a threshold cost-effectiveness analysis of INSPIRE, an HIV prevention intervention for sero-positive injection drug users (IDUs). The intervention is being conducted in four U.S. cities (Baltimore, Miami, New York, and San Francisco) with support from the Centers for Disease Control and Prevention and the Health Resources & Services Administration. The goals are to prevent HIV transmission due to high-risk sexual and drug injection behaviors; to increase access to, use of, and maintenance in primary HIV health care; and to increase access to, use of, and adherence to HIV treatment. The research team has prioritized sexual risk reduction as the most important goal. This analysis was carried out to determine the cost of the INSPIRE intervention and determine whether the intervention is likely to be cost-effective from a societal perspective. The assessment focused primarily on HIV infections prevented through sexual risk reduction (and secondarily on those prevented by safer injection practices). Cost-effectiveness implications of INSPIRE's other goals were not assessed.

METHODS: Researchers at each of the four sites collected data on program and participant costs (the latter included income loss, and costs of child and elderly care and transportation). A mathematical model was developed to estimate the number of sex partners of IDUs expected to become infected with HIV (with and without the intervention), cost of treatment for sex partners who became infected, and the effect of infection on partners' quality-adjusted life expectancy (measured as quality-adjusted life years -- QALYs). The model was used to determine the minimum impact that INSPIRE must have on condom usage among trial participants for the intervention to be considered cost-saving or cost-effective. "Cost-saving" means the cost of the intervention is less than the savings it generates by preventing infection. "Cost-effective" in this analysis means the net cost (that is the cost of the intervention after subtracting the savings) per QALY saved is less than $50,000. Extensive sensitivity analyses were carried out to assess the robustness of threshold values.

RESULTS: The intervention cost $859 per participant, of which 95% was the cost to the program and 5% to participants. In the base case analysis, the intervention would be cost-saving if it were associated with a 52% decrease in the proportion of participants who had unprotected sex over a one-year period. To be cost-effective, the intervention must be associated with a 17% decrease. The thresholds were found to be sensitive to the expected duration of behavior change. If behavior change persisted only for 3 months, the cost-effectiveness threshold was 65%; if participants maintained protective behaviors for three years, the threshold fell to 6%.

CONCLUSIONS: The costs of the INSPIRE intervention are similar to those described in the literature for other small group behavioral interventions for HIV prevention. The costs for IDU participation are low. Cost-effectiveness thresholds under base case and most sensitivity analyses scenarios appear achievable. Cost-saving thresholds do not.

030727
M1-E0601

Copyright notice: The National HIV Prevention Conference is collaborative effort by the Centers for Disease Control and Prevention, a U.S. Government agency and other governmental and non-government organizations. All abstracts published in by the conference organizers are in the public domain and can be used without permission. Proper citation, however, is required.