Methadone maintenance treatment and mortality in people with criminal convictions: a population-based retrospective cohort study from Canada.

Why was this study done? • Individuals with criminal histories experience high rates of opioid dependence and premature mortality. • Deaths caused by opioids are rising acutely and offenders are at risk. • Adherence to opioid substitution treatments (OSTs), such as methadone, has been shown to reduce the risk of death during custody and immediately following release. • Little is known about the long-term association between methadone adherence and mortality. What did researchers do and find? • This study integrated population-level data including prescriptions, convictions, and deaths in British Columbia (BC), Canada spanning 1998–2015. • We examined the risk of all-cause and cause-specific death among 14,530 people with criminal convictions who had been prescribed methadone. • Overall and cause-specific mortality rates were compared between periods when methadone was and was not dispensed. • Periods when methadone was dispensed were associated with lower risk of mortality, including overdose fatalities, after controlling for covariates. What do these findings mean? • Practices to increase methadone adherence among opioid-dependent offenders are required and may reduce overdose-related, as well as other causes of, premature death.