Methadone maintenance and the likelihood of risky needle-sharing.

Survey data were used to study the association of methadone maintenance and needle-sharing. An ordinal scale of HIV risk was derived from the number of persons from whom subjects reported accepting a used needle and syringe in the 6 months prior to interview. The odds of respondents in methadone maintenance being in the higher risk group were half those of daily heroin users not in treatment for all three transitions in a four-level ordinal scale of risk (OR 0.55, 95% CL 0.33 to 0.90, ordinal logistic regression). This association disappeared when methadone patients who had not injected in the month prior to interview were excluded from the analysis. Subjects' knowledge concerning HIV and AIDS had no measurable association with the outcome. It is concluded that methadone maintenance reduces heroin addicts' risk of infection with HIV by reducing the likelihood of their injecting drugs rather than by changing their injecting behavior.