Opioid substitution treatment (OST) with methadone maintenance to reduce mortality — evidence summary

Summary of the evidence


Opioid substitution treatment (OST) with methadone maintenance was found to be effective in systematic reviews (Mattick et al., 2009, Bargagli A.M. et al., 2007, Mathers et al., 2013) in:

  • reducing the risk of death:
    • mortality (any cause): three RCTs (N= 435) (RR 0.493, 95 % CI, 0.06 to 4.23) (1)
    • mortality (any cause): five observational studies (N= 69970) (RR 0.3795, 95 % CI 0.29 to 0.48)
    • mortality during in-treatment and off-treatment periods at follow-up: six observational studies (RR 2.52, 95 % CI 1.50 to 4.00)
    • reducing risk of overdose death for those retained in treatment compared to those waiting for treatment, those who have left treatment or those that are in detoxification treatment:
    • five observational studies (N=69 970) (RR 0.17, 95 % CI 0.05 to 0.63)

(1): the measure from the RCT is not statistically significant, nevertheless the evidence when considered together with the results of the observational studies, is significant.


Note: this evidence summary is only valid for the outcomes, target groups, settings and substances/patterns of use described below.

Name of response option:
Pharmacological treatment
Desired outcome(s):
reduce mortality
Harm reduction
Specific substance or pattern of use:
Target group(s) or setting(s):
PWID – people who inject drugs