Citation

Pierce M, Millar T, Robertson JR, Bird SM. Int. J. Drug Policy 2018; 55: 121-127.

Affiliation

Usher Institute of Population Health Sciences and Informatics, University of Edinburgh, Edinburgh EH16 4UX, United Kingdom; MRC Biostatistics Unit, University of Cambridge, School of Clinical Medicine, Institute for Public Health, Cambridge CB2 0SR, United Kingdom; Department of Mathematics and Statistics, University of Strathclyde, Glasgow G1 1XH, United Kingdom. Electronic address: sheila.bird@mrc-bsu.cam.ac.uk.

Copyright

(Copyright © 2018, Elsevier Publishing)

DOI

10.1016/j.drugpo.2018.02.005

PMID

29573622

Abstract

BACKGROUND: 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.

METHODS: The setting is all services in England that provide publicly-funded, structured treatment for illicit opioid users, the methodology linkage of the English National Drug Treatment Monitoring System and mortality database, and key measurements are DRDs, methadone-specific DRDs, or heroin-specific DRDs, by age-group and gender, with proportional hazards adjustment for substances used, injecting status and periods in/out of treatment.

RESULTS: Linkage was achieved for 129,979 adults receiving prescribing treatment modalities for opioid dependence during April 2005 to March 2009 and followed-up for 378,009 person-years (pys). There were 1,266 DRDs: 271 methadone-specific (7 per 10,000 pys: irrespective of gender) and 473 heroin-specific (15 per 10,000 pys for males, 7 for females). Methadone-specific DRD-rate per 10,000 person-years was 3.5 (95% CI: 2.7-4.4) at 18-34 years, 8.9 (CI: 7.3-10.5) at 35-44 years and 18 (CI: 13.8-21.2) at 45+ years; heroin-specific DRD-rate was unchanged with age. Relative to 25-34 years, pooled HRs for UK clients' methadone-specific deaths were: 0.87 at <25 years (95% CI: 0.56-1.35); 2.14 at 35-44 years (95% CI: 1.76-2.60); 3.75 at 45+ years (95% CI: 2.99-4.70).

CONCLUSION: International testing and explanation are needed of UK's sharp age-related increase in the risk of methadone-specific death. Clients should be alerted that their risk of methadone-specific death increases as they age.

Copyright © 2018 The Authors. Published by Elsevier B.V. All rights reserved.

Language: en

Keywords

Age-related hazard ratios; Age-relatedness; Drug-related deaths; Gender; Methadone-specific deaths; Pooling; Risk behaviours