Mortality among individuals prescribed opioid-agonist therapy in Scotland, 2011–2020: a national retrospective cohort study
Background / Aims: Scotland’s drug-related death (DRD) rate has increased rapidly to one of the highest in the world. Our aim was to examine the extent to which opioid-agonist therapy (OAT) in Scotland is protective against drug-related mortality and how this effect has varied over time.
Methods: We included individuals in Scotland with opioid use disorder who received at least one OAT prescription between 1 January 2011 and 31 December 2020. We calculated drug-related mortality rates and used Quasi-Poisson regression models to estimate trends over time and by OAT exposure, adjusting for potential confounding.
Results: In a cohort of 46,453 individuals prescribed OAT with a total of 304,000 person-years of follow-up, DRD rates more than trebled from 6·36 per 1,000 person-years (95% CI: 5·73 to 7·01) in 2011–12 to 21.45 (95% CI: 20·31 to 22·63) in 2019–20. DRD rates were almost three and a half times higher (HR 3·37, 95% CI: 1·74 to 6·53) for those off OAT at the time of death relative to those on OAT after adjustment for confounders. However, DRD risk increased over time after adjustment for both people off and on OAT.
Conclusions: Drug-related mortality rates among people with opioid use disorders in Scotland increased between 2011 and 2020. OAT remains protective, but is insufficient on its own to slow the increase in DRD risk experienced by people who are opioid dependent in Scotland.