Methadone Linked to Lower Death Risk for Opioid Survivors

For individuals who have survived an opioid overdose, initiating treatment with methadone was associated with a reduced risk of death within the subsequent year when compared to starting treatment with buprenorphine-naloxone, according to a retrospective cohort study conducted in Canada. The study utilized data from the Ontario healthcare system, encompassing individuals who received their first prescription for either methadone or buprenorphine-naloxone between April 1, 2017, and March 31, 2022. Researchers identified 10,895 individuals who initiated methadone treatment and 10,895 matched individuals who initiated buprenorphine-naloxone treatment. The primary outcome measured was all-cause mortality occurring within 365 days of the index prescription date. The findings indicated a statistically significant difference in mortality rates between the two treatment groups. Specifically, the hazard ratio for death within one year for those starting methadone compared to those starting buprenorphine-naloxone was 0.61, with a 95% confidence interval of 0.46 to 0.81. This suggests that methadone treatment was associated with approximately a 39% reduction in the risk of death. The study also examined secondary outcomes, including hospitalizations for opioid use disorder and emergency department visits related to opioid use. The researchers controlled for a range of demographic and clinical factors, such as age, sex, comorbidities, previous healthcare utilization, and geographic region, to minimize potential confounding variables. The study's design as a retrospective cohort analysis means it can identify associations but cannot definitively establish causation. However, the large sample size and robust statistical methods employed lend weight to the observed association. Methadone and buprenorphine-naloxone are both medications used in Medication for Opioid Use Disorder (MOUD) treatment, aiming to reduce cravings and withdrawal symptoms, thereby supporting recovery and reducing the risk of overdose. Methadone is a full opioid agonist, while buprenorphine is a partial opioid agonist, and naloxone is an opioid antagonist included in some formulations to deter misuse. The study's findings contribute to the ongoing discussion about optimal treatment strategies for opioid use disorder, particularly for individuals at high risk following an overdose. The Canadian healthcare system's comprehensive data collection allowed for a detailed examination of treatment outcomes in a real-world setting. Further research, potentially including randomized controlled trials, would be beneficial to confirm these findings and explore the mechanisms underlying the observed difference in mortality risk. The implications of this study could inform clinical guidelines and public health policies aimed at improving survival rates among opioid overdose survivors. The study was published in JAMA Network Open on May 29, 2024. The research team included individuals from the University of Toronto and the Institute for Clinical Evaluative Sciences.