Simon Fraser UniversityOct 21 2024

People with opioid use disorder in British Columbia who received methadone had a 37-40 per cent lower rate of treatment discontinuation compared with those who received buprenorphine/naloxone.

The new research, published this week in the Journal of the American Medical Association, evaluated the risk of treatment discontinuation and mortality in people prescribed opioid agonist treatment (OAT) over a 10-year period.

Reducing the risk of treatment discontinuation saves lives. With thousands of lives lost since the introduction of fentanyl into B.C.'s unregulated drug supply, it is important that we continue to evaluate the best available treatment options. Comparative studies like this using high-quality health administrative data are one of the best sources of evidence we have to evaluate how our treatment options are performing as the toxic drug supply continues to evolve."

Dr. Bohdan Nosyk, Scientist, Centre for Advancing Health Outcomes and Professor, Faculty 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 Centre for Advancing Health Outcomes, Simon Fraser University, BC Centre on Substance Use, University of British Columbia (UBC), and McGill University in Canada, and universities and institutions in the United Kingdom, Austria, and across the United States.

This study included everyone in B.C. who received either methadone or buprenorphine/naloxone for opioid use disorders from Jan 1, 2010 to Mar 17, 2020 (30,891 people) and compared the impact of these medications on retention and all-cause mortality. Fentanyl was first detected in the drug supply in 2012 and became the primary driver of overdose mortality in 2016. The study period ended the day before BC declared a public health emergency for COVID-19. Just over 61 per cent of people in the cohort were prescribed methadone.

The study found that the risk of treatment discontinuation was lower among recipients of methadone compared with buprenorphine/naloxone. The risk of mortality was low during treatment and did not differ meaningfully between the two medications (0.13% vs. 0.08%). Importantly, these findings were consistent after the introduction of fentanyl and across patient subgroups, including youth (<24 years), people with severe mental disorders, and people with concurrent chronic pain.

"The benefits of these medications are only realized while people are using them. However, retention in OAT 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 for the BC Centre on Substance Use, and a co-author on the study. "Continuous evaluation and refinement of clinical guidance based on the strongest available evidence is vital in order to provide the best possible support to people with opioid use disorder in BC and around the world."

Earlier research shows that mortality risk for people on OAT more than doubles after treatment discontinuation versus while on treatment.

The researchers noted that while this evidence suggests that methadone remains the treatment option with the strong evidence of effectiveness, decisions about medication choice must be made in collaboration with patients. Developing novel therapeutic regimens, like co-prescription of hydromorphone, is also an urgent priority. Additionally, there needs to be consideration the existing barriers to treatment retention, like urine drug screening and daily witnessed doses, and incorporation of strategies to improve retention, like engagement of peer support workers.

Simon Fraser University

Journal reference:

Nosyk, B., et al. (2024). Buprenorphine/Naloxone vs Methadone for the Treatment of Opioid Use Disorder. JAMA. doi.org/10.1001/jama.2024.16954.