Opioid substitution therapy includes supplying illicit drug users with replacement drugs like methadone and buprenorphine. The objective of this study is to compare the risk of all-cause and overdose mortality in people with opioid dependence during and after receiving opioid substitution treatment.

This systematic review and meta-analysis included a total of 19 eligible cohorts that comprised people with opioid dependence and reported deaths from all causes or overdose after or during an opioid substitution treatment with methadone or buprenorphine. The primary outcome of the study was all-cause and overdose mortality.

The 19 eligible cohorts included 12,885 people treated with methadone and 15,831 people treated with buprenorphine. Pooled analysis indicated a mortality rate of 11.3 and 36.1 per 1,000 person-years in and out of methadone treatment. The rate was reduced to 4.3 and 9.5 per 1,000 person-years in and out of buprenorphine treatment. The pooled trend analysis exhibited a strong decline in all-cause mortality over the first 4 weeks, followed by a gradual decline over the next 2 weeks. The rate of overdose mortality was 2.6 and 12.7 per 1,000 person-years in and out of methadone treatment and 1.4 and 4.6 in and out of buprenorphine treatment.

The research concluded that retention in methadone and buprenorphine treatment was associated with a reduced risk of all-cause and overdose mortality.

Ref: https://www.bmj.com/content/357/bmj.j1550