Four-year follow-up of imprisoned male heroin users and methadone treatment: mortality, re-incarceration and hepatitis C infection

Abstract

Aims: To examine the long-term impact of methadone maintenance treatment (MMT) on mortality, re-incarceration and hepatitis C seroconversion in imprisoned male heroin users.

Design, setting and participants: The study cohort comprised 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.

Measurements: All-cause mortality, re-incarceration, hepatitis C and HIV serostatus and MMT retention.

Findings: There were no deaths 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% CI, 1.2-3.2). Re-incarceration risk was lowest during MMT episodes of 8 months or longer (adjusted hazard ratio 0.3 (95% 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% CI, 5-76; < P = 0.001)] and MMT episodes less than 5 months [adjusted hazard ratio 4.2 (95% 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% CI, 7.0-15.7; P < 0.001). HIV incidence was 0.3 per 100 person-years (95% CI, 0.03-0.99).

Conclusions: Retention in MMT was associated with reduced mortality, re-incarceration rates and hepatitis C infection. Prison-based MMT programmes are integral to the continuity of treatment needed to ensure optimal outcomes for individual and public health.