Retention in methadone treatment is associated with a substantial reduction in the risk for all-cause and overdose mortality in patients dependent on opioids, according to a study published in the BMJ.
Luis Sordo, MD, PhD, from the National Centre for Epidemiology at the Carlos III Institute of Health in Madrid, and colleagues conducted a systematic review and meta-analysis of prospective or retrospective cohort studies in people with opioid dependence that reported deaths from all causes or overdose during follow-up periods in and out of opioid substitution treatment with methadone or buprenorphine.
There were 19 eligible cohorts, following 122,885 people treated with methadone for 1.3 to 13.9 years and 15,831 people treated with buprenorphine for 1.1 to 4.5 years. Pooled all-cause mortality rates were 11.3 and 36.1 per 1000 person years in and out of methadone treatment (unadjusted out-to-in rate ratio, 3.20) and reduced to 4.3 and 9.5 in and out of buprenorphine treatment (2.20).
In pooled trend analysis, all-cause mortality decreased during the first 4 weeks of methadone treatment and decreased gradually 2 weeks after leaving treatment. All-cause mortality remained stable during induction and remaining time on buprenorphine treatment. Overdose mortality had a pooled overdose mortality rate of 2.6 and 12.7 per 1000 person years in and out of methadone treatment (unadjusted out-to-in rate ratio, 4.80), and 1.4 and 4.6 in and out of buprenorphine treatment.
“Our review suggests that time spent in opioid substitution treatment with methadone is associated with an average reduction of 25 deaths/1000 person years,” the authors stated. “Findings also suggest that opioid substitution treatment with buprenorphine could be associated with a reduction in mortality, with a similar risk across all time in treatment (about 4 deaths/1000 person years) consistent with its safety profile and a risk after cessation higher in the first 4 weeks than in the remainder of time out of treatment.”
- Sordo L, Barrio G, Bravo MJ, et al. Mortality risk during and after opioid substitution treatment: systematic review and meta-analysis of cohort studies. BMJ. 26 April 2017. doi: 10.1136/bmj.j1550