Research Paper
Ageing opioid users’ increased risk of methadone-specific death in the UK

https://doi.org/10.1016/j.drugpo.2018.02.005Get rights and content
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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.

Keywords

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

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