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

• Published in: PLoS medicine 2018-07, Vol.15 (7), p.e1002625
• Main Authors: Russolillo, Angela, Moniruzzaman, Akm, Somers, Julian M
• Format: Article
• Language: English
• Subjects: Accidental poisoning; Addictions; Adolescent; Adult; Aged; Analgesics, Opioid - administration & dosage; Analgesics, Opioid - adverse effects; Analysis; Biology and Life Sciences; British Columbia - epidemiology; Canada; Care and treatment; Cause of Death; Cohort analysis; Control; Convictions; Criminal sentences; Criminals; Death; Dependence; Drug dependence; Drug dosages; Ex-convicts; Fatalities; Female; Health aspects; Health sciences; Heroin; Humans; Imprisonment; Infectious diseases; Male; Medication Adherence; Medicine and Health Sciences; Methadone; Methadone - administration & dosage; Methadone - adverse effects; Methadone maintenance; Middle Aged; Mortality; Narcotics; Opiate Substitution Treatment - adverse effects; Opiate Substitution Treatment - mortality; Opioid abuse; Opioid-Related Disorders - diagnosis; Opioid-Related Disorders - mortality; Opioid-Related Disorders - rehabilitation; Opioids; Overdose; Patient compliance; Patient outcomes; People and places; Population; Population studies; Population-based studies; Prisoners; Prisons; Protective Factors; Public health; Retrospective Studies; Risk Assessment; Risk Factors; Stigma; Studies; Substance abuse treatment; Systematic review; Time Factors; Treatment Outcome; Young Adult
• ISSN: 1549-1676; 1549-1277; 1549-1676
• DOI: 10.1371/journal.pmed.1002625

Individuals with criminal histories have high rates of opioid dependence and mortality. Excess mortality is largely attributable to overdose deaths. Methadone maintenance treatment (MMT) is one of the best evidence-based opioid substitution treatments (OSTs), but there is uncertainty about whether methadone treatment reduces the risk of mortality among convicted offenders over extended follow-up periods. The objective of this study was to investigate the association between adherence to MMT and overdose fatality as well as other causes of mortality. We conducted a retrospective cohort study involving linked population-level administrative data among individuals in British Columbia (BC), Canada with a history of conviction and who filled a methadone prescription between January 1, 1998 and March 31, 2015. Participants were followed from the date of first-dispensed methadone prescription until censoring (date of death or March 31, 2015). Methadone was divided into medicated (methadone was dispensed) and nonmedicated (methadone was not dispensed) periods and analysed as a time-varying exposure. Hazard ratios (HRs) with 95% CIs were estimated using multivariable Cox regression to examine mortality during the study period. All-cause and cause-specific mortality rates were compared during medicated and nonmedicated methadone periods. Participants (n = 14,530) had a mean age of 34.5 years, were 71.4% male, and had a median follow-up of 6.9 years. A total of 1,275 participants died during the observation period. The overall all-cause mortality rate was 11.2 per 1,000 person-years (PYs). Participants were significantly less likely to die from both nonexternal (adjusted HR [AHR] 0.27 [95% CI 0.23-0.33]) and external (AHR 0.41 [95% CI 0.33-0.51]) causes during medicated periods, independent of sociodemographic, criminological, and health-related factors. Death due to infectious diseases was 5 times lower (AHR 0.20 [95% CI 0.13-0.30]), and accidental poisoning (overdose) deaths were nearly 3 times lower (AHR 0.39 [95% CI 0.30-0.50]) during medicated periods. A competing risk regression demonstrated a similar pattern of results. The use of a Canadian offender population may limit generalizability of results. Furthermore, our observation period represents community-based methadone prescribing and may omit prescriptions administered during hospital separations. Therefore, the magnitude of the protective effects of methadone from nonexternal causes of death should be inte