People with opioid use disorder in British Columbia who received methadone had a 37-40 percent lower dropout rate compared to those who received buprenorphine/naloxone.
The new research, published this week in the Journal of the American Medical Associationassessed the risk of discontinuation and mortality in subjects prescribed opioid agonist therapy (OAT) over a 10-year period.
Reducing the risk of treatment discontinuation saves lives. With thousands of lives lost from the introduction of fentanyl into BC’s unregulated drug supply, it is important that we continue to evaluate the best treatment options available. Comparative studies like this one using high-quality administrative health data are one of the best sources of evidence we have to assess the performance of our treatment options as the toxic drug supply continues to evolve.”
Dr. Bohdan Nosyk, Scientist, Center for Advancing Health Outcomes and Professor, School of Health Sciences at Simon Fraser University
The study, buprenorphine/naloxone versus methadone for the treatment of opioid use disorder, was a collaboration between scientists and public health professionals from the Center for Advancing Health Outcomes, Simon Fraser University, BC Center on Substance Use, University of British Columbia (UBC), and McGill University in Canada, and universities and institutions in the United Kingdom, Austria, and throughout the United States.
This study included everyone in BC. who received either methadone or buprenorphine/naloxone for opioid use disorders from January 1, 2010 to March 17, 2020 (30,891 subjects) and compared the effect of these medications on retention and all-cause mortality. Fentanyl was first detected in the drug supply in 2012 and became the leading cause of overdose death in 2016. The study period ended the day before BC declared a public health emergency for COVID-19. Just over 61 percent of people in the cohort were prescribed methadone.
The study found that the risk of treatment discontinuation was lower among methadone recipients compared to buprenorphine/naloxone. The risk of mortality was low during treatment and did not differ significantly between the two drugs (0.13% vs. 0.08%). Importantly, these findings were consistent after the introduction of fentanyl and across patient subgroups, including the young (<24 years), those with severe mental disorders, and those with concurrent chronic pain.
“The benefits of these drugs are only realized when people use them. However, OAT retention has steadily declined over the past 13 years,” said Dr. Paxton Bach, Clinical Assistant Professor in the Department of Medicine at UBC, Co-Medical. Director of the BC Center on Substance Use, and co-author of the study. “Continued evaluation and improvement of clinical guidance based on the strongest available evidence is critical to providing the best possible support to people with opioid use disorder in BC and around the world.”
Previous research shows that the risk of mortality for people with OAT more than doubles after stopping treatment compared with the duration of treatment.
The researchers noted that while this evidence suggests that methadone remains the treatment option with strong evidence of efficacy, decisions about drug choice must be made in collaboration with patients. The development of new treatment regimens, such as prescription hydromorphone, is also an urgent priority. In addition, existing barriers to treatment retention, such as urine drug testing and daily dosing, must be considered, as well as the incorporation of strategies to improve retention, such as the engagement of peer support workers.
Source:
Journal Reference:
Nosyk, B., et al. (2024). Buprenorphine/Naloxone vs Methadone for the Treatment of Opioid Use Disorder. GLASS. doi.org/10.1001/jama.2024.16954.
