Cost-effectiveness of an HIV risk reduction intervention for adults with severe mental illness.

Small-group HIV prevention interventions that focus on individual behavioural change have been shown to be especially effective in reducing HIV risk among persons with severe mental illness. Because economic resources to fund HIV prevention efforts are limited, health departments, community planning groups and other key decision-makers need reliable information on the cost and cost-effectiveness (not solely on effectiveness) of different HIV prevention interventions. This study used an economic evaluation technique known as cost-utility analysis to assess the cost-effectiveness of three related cognitive-behavioural HIV risk reduction interventions: a single-session, one-on-one intervention; a multi-session small-group intervention; and a multi-session small-group intervention that taught participants to act as safer sex advocates to their peers. For men, all three interventions were cost-effective, but advocacy training was the most cost-effective of the three. For women, only the single-session intervention was cost-effective. The gender differences observed here highlight the importance of focusing on gender issues when delivering HIV prevention interventions to men and women who are severely mentally ill.