Characteristics of methadone related overdose deaths and comparisons between those dying on and off methadone substitution treatment: a national cohort study.

Abstract

Background: Opioid users, particularly those with a history of injecting and dependence, have a high risk of fatal polysubstance and methadone related overdose. Aim: To describe characteristics of methadone related overdose deaths and assess if differences exist between those dying on and off opioid agonist treatment (OAT). Methods: A descriptive study of all persons dying of drug overdose involving methadone on the Irish National Drug Related Deaths Index (NDRDI) in 2012 and 2013. Results: A total of 182 methadone implicated deaths were recorded . 78% (n=142) were male; with a mean age of 36 years. Of the cohort, 61% (n=111) were not in receipt of opiate agonist treatment (OAT) at the time of death, 15.9% (n=29) had a previous history of non-fatal overdose and 24.7% (n=45) a history of alcohol dependence. Analysis and interpretations are limited by incomplete data on other characteristics but where available show that 89% (n=73) were injecting drug users, with 57.8% (n=26) injecting drugs at the time of death. History of mental illness was recorded in 96.3% (n=77) of cases, with 94.7% (n=107) having history of substance dependency treatment. Polysubstances were implicated in 86.8% (n=158) of deaths. The majority died in a private dwelling (74.7% n= 127) and were not alone 67.4% (n=114). Conclusions: Methadone related fatal overdose is a significant cause of death in young Irish, who share many characteristics with other drug related deaths. Improved monitoring, risk assessment and OAT retention strategies is warranted to inform national drug overdose plans and overdose prevention