By Matthias Pierce, Tim Millar, J. Roy Robertson, Sheila M. Bird 

What is known already

•The first evidence that the hazard ratio (HR) for methadone-specific death rises more steeply with age-group than for all drug-related deaths (DRDs) came from Scotland’s cohort of 33,000 methadone-prescription clients. We aim to examine, for England, whether illicit opioid users’ risk of methadone-specific death increases with age; and to pool age-related HRs for methadone-specific deaths with those for Scotland’s methadone-prescription clients.

• Despite harm reduction measures, such as opioid substitution therapy, UK’s DRDs have increased markedly in the past decade, in a strongly age-related manner.

• One powerful record-linkage study on Scotland’s methadone-prescription clients in 2009–2013 has shown that their adjusted hazard ratios for methadone-specific DRD increased sharply by age-group, irrespective of gender.

What this study adds

• By analysing the opioid-specificity of deaths for England’s National Drug Treatment Monitoring System (NDTMS) cohort of nearly 130,000 opioid users who started a prescribing treatment modality, predominantly methadone, during 1 April 2005 to 31 March 2009, we confirmed that their hazard ratios for methadone-specific DRDs also increased sharply by age-group.

• Importantly, nearly half of the cohort’s person-years were aged 35+ years; and age-effects persisted after adjustment for risk-behaviours.