This study examined the long-term impact of methadone maintenance treatment (MMT) on mortality, re-incarceration, and hepatitis C seroconversion in imprisoned male heroin users.
The study cohort consisted of 382 imprisoned male heroin users who had participated in a randomized controlled trial of prison-based MMT in 1997/98. Subjects were followed up between 1998 and 2002 either in the general community or in prison. The study collected data on all-cause mortality, re-incarceration, hepatitis C, and HIV serostatus and MMT retention. No deaths were recorded while subjects were enrolled in MMT. Seventeen subjects died while out of MMT, representing an untreated mortality rate of 2.0 per 100 person-years (95 percent CI, 1.2-3.2). Re-incarceration risk was lowest during MMT episodes of 8 months or longer (adjusted hazard ratio 0.3 (95 percent CI, 0.2-0.5; P<0.001), although MMT periods 2 months or less were associated with greatest risk of re-incarceration (P<0.001). Increased risk of hepatitis C seroconversion was significantly associated with prison sentences of less than 2 months [adjusted hazard ratio 20 (95 percent CI, 5-76;<=0.001)] and MMT episodes less than 5 months [adjusted hazard ratio 4.2 (95 percent CI, 1.4-12.6; P=0.01)]. Subjects were at greatest risk of MMT dropout during short prison sentences of 1 month or less (adjusted hazard ratio 10.4 (95 percent CI, 7.0-15.7; P<0.001). HIV incidence was 0.3 per 100 person-years (95 percent CI, 0.03-0.99). The study concluded that retention in MMT was associated with reduced mortality, re-incarceration rates, and hepatitis C infection. Prison-based MMT programs are integral to the continuity of treatment needed to ensure optimal outcomes for individual and public health. (publisher abstract modified)