RESUMO
AIM: Although opioid substitution therapy (OST) immediately after prison release reduces mortality, the cost-effectiveness of treatment has not been examined. Therefore, we undertook a cost-effectiveness analysis of OST treatment upon prison release and the prevention of death in the first 6 months post-release. DESIGN: Population-based, retrospective data linkage study using records of OST entrants (1985-2010), charges and court appearances (1993-2011), prison episodes (2000-11) and death notifications (1985-2011). SETTING: New South Wales, Australia. PARTICIPANTS: A cohort of 16,073 people with a history of opioid dependence released from prison for the first time between 1 January 2000 and 30 June 2011. INTERVENTION: OST treatment compared to no OST treatment at prison release. MEASUREMENTS: Mortality and costs (treatment, criminal justice system-court, penalties, prison-and the social costs of crime) were evaluated at 6 months post-release. Analyses included propensity score matching, bootstrapping and regression. FINDINGS: A total of 13,468 individuals were matched (6734 in each group). Twenty (0.3%) people released onto OST died, compared with 46 people (0.7%) not released onto OST. The final average costs were lower for the group that received OST post-release ($7206 versus $14,356). The incremental cost-effectiveness ratio showed that OST post-release was dominant, incurring lower costs and saving more lives. The probability that OST post-release is cost-effective per life-year saved is 96.7% at a willingness to pay of $500. CONCLUSION: Opioid substitution treatment (compared with no such treatment), given on release from prison to people with a history of opioid dependence, is cost-effective in reducing mortality in the first 6 months of release.