Home > Do interruptions to the continuity of methadone maintenance treatment in specialist addiction settings increase the risk of drug-related poisoning deaths? A retrospective-cohort study.

Durand, Louise and O'Driscoll, Denis and Boland, Fiona and Keenan, Eamon and Ryan, Benedict and Barry, Joseph and Bennett, Kathleen and Fahey, Tom and Cousins, Gráinne (2020) Do interruptions to the continuity of methadone maintenance treatment in specialist addiction settings increase the risk of drug-related poisoning deaths? A retrospective-cohort study. Addiction , Early online .

URL: https://onlinelibrary.wiley.com/doi/abs/10.1111/ad...

AIMS: To examine the risk of mortality associated with interruptions to the continuity of methadone maintenance treatment (MMT), including transfers between services, in opioid dependent individuals attending specialist addiction services.

DESIGN: Retrospective cohort study using addiction services and primary care dispensing records, the national methadone register and national drug related death index (NDRDI).
SETTING: Geographically defined population in Dublin, Ireland.
PARTICIPANTS: A total of 2,899 people prescribed and dispensed methadone in specialist addiction services between January 2010 and December 2015. There were 5 exposure groups: weeks 1-4 following transfer between treatment providers; weeks 1-4 out of treatment; weeks 5-52 out of treatment; weeks 1-4 of treatment initiation; and weeks 5+ of continuous treatment (reference category).

MEASUREMENTS: Primary outcome: drug related poisoning (DRP) deaths. Secondary outcome: all-cause mortality (ACM). Mortality rates calculated by dividing number of deaths (DRP; ACM) in exposure groups by person-years exposure. Unadjusted and adjusted Poisson regression (covariates age, sex, incarceration, methadone dose and co-morbidities) estimated differences in mortality rates.

FINDINGS: There were 154 ACM deaths, 55 (35.7%) identified as DRP deaths. No deaths were observed in the first month following transfer between treatment providers. The risk of DRP mortality was highest in weeks 1-4 out of treatment (ARR 4.04, 95% CI 1.43-11.43, p=0.009) and weeks 1-4 of treatment initiation (ARR 3.4, 95% CI 1.2-9.64, p =0.02). Similarly, risk of ACM was highest in weeks 1-4 out of treatment (ARR 11.78, 95% CI 7.73-17.94, p<0.001), weeks 1-4 of treatment initiation (ARR 5.11, 95% CI 2.95-8.83, p<0.001) and weeks 5-52 off treatment (ARR 2.04, 95% CI 1.2-3.47, p=0.009).

CONCLUSIONS: Interruptions to the continuity of methadone maintenance treatment by treatment provider do not appear to be periods of risk for drug related poisoning or all-cause mortality deaths. Risk of drug related poisoning and all-cause mortality deaths appears to be greatest during the first four weeks of treatment initiation/re-initiation and after treatment cessation.


Item Type:Article
Date:February 2020
Volume:Early online
EndNote:View
Related URLs:
Subjects:HJ Treatment method > Substance disorder treatment method > Substance replacement method (substitution) > Methadone maintenance
P Demography, epidemiology, and history > Population dynamics > Substance related mortality / death
VA Geographic area > Europe > Ireland

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