About the Project
Hypothesis: There may be varying individual-level clinical and sociodemographic factors, area-level socioeconomic patterns, and temporal trends in risks for natural and unnatural causes of death in patients receiving opiate substitution treatment across the UK that may provide important novel insights into prevention.
Why is this unique? In the UK, much routine treatment for opiate addiction is provided by general practitioners - the so-called “British system” - and prescribing of opioid agonist substitution treatment via methadone or buprenorphine in primary care has increased markedly since the 1990s. The central ethos of this approach has been harm minimisation, and other countries are now expanding provision of opiate substitution treatment (OST) into primary care in a similar way. However, treatment with methadone in primary care has been described as a “double-edged sword” because, although opioid substitution treatment is associated with substantial reductions in mortality risk, methadone itself is associated with drug-related deaths. Findings from this work have the potential to improve care for vulnerable populations and inform both national and international public health guidance on risk minimisation via opiate substitution pathways in primary care.
Why is this important? Opiate users have an elevated risk of death and contribute substantially to adult mortality. Eighty percent of deaths related to drug misuse involve opiate users. The risk of death during and after opiate substitution treatment appears to be non-uniform. Treatment guidelines and recent studies have suggested that the start of treatment (the first 28 days) may be associated with an increased risk of death. Furthermore, findings in large cohorts in England, Italy and Australia have suggested that an excess risk of death exists in the period immediately after treatment ends. Concurrent use/misuse of sedative drugs is a known risk factor for fatal overdose and high levels of co-prescribing of sedative drugs have been observed in primary care settings in the UK. Emerging evidence indicates that risk of methadone-specific overdose may be increasing in the UK’s ageing opioid misusing population, potentially as a consequence of elevated physical (liver) co-morbidity and thus slow metabolism in this group. Thus higher prescribed doses may present particular risks to some patients. Conversely, concerns have also been raised about under-dosing, which may elevate risk due to the increased likelihood of illicit use “on top”. We plan to examine the relationship between opiate substitution treatment delivered in UK primary care and cause-specific mortality, investigate whether risk of death is elevated in the first few weeks of treatment and in the period immediately after treatment, consider the potential impact of OST dose on risk, co-prescription of sedative drugs and physical co-morbidities, and examine the potential influence of opiate substitution treatment on drug-related mortality for different durations of treatment.
Entry Requirements
Candidates are expected to hold, or about to obtain, a minimum upper second class undergraduate degree (or equivalent) in a health sciences, statistical or social sciences subject; a relevant master’s degree in one of these disciplines is also desirable, with a particular preference for public health, & epidemiology or statistics.
For information on how to apply for this project, please visit the Faculty of Biology, Medicine and Health Doctoral Academy website (https://www.bmh.manchester.ac.uk/study/research/apply/).If you are interested, please make direct contact with the Supervisor to discuss the project. You MUST also submit an online application form - choose PhD Epidemiology.
References
Hickman, M., Steer, C., Tilling, K., Lim, A., Marsden, J., Millar, T., Strang, J., Telfer, M., Vickerman, P. & Macleod, J. The impact of buprenorphine and methadone on mortality: a primary care cohort study in the United Kingdom. Addiction 2018: 113, (8): 1461-1476.
Pierce, M., Millar, T., Robertson, J.R., Bird, S.M., (2018) ‘Ageing opioid users' increased risk of methadone-specific death in the UK’ International Journal of Drug Policy 55:121-127
Pierce, M., Bird, S.M., Hickman, M., Marsden, J., Dunn, G., Seddon, T., Millar, T. (2018) ‘Effect of initiating drug treatment on the risk of drug-related poisoning death and acquisitive crime among offending heroin users’ International Journal of Drug Policy 51: 42-51
Pierce, M., Bird, SM., Hickman, M., Marsden, J., Dunn, G., Jones, A., Millar, T. (2016) ‘Impact of treatment for opioid dependence on fatal drug-related poisoning: a national cohort study in England’ Addiction 11(2): 298-308
Pierce, M., Bird, S.M., Hickman M., & Millar, T. (2015) ‘National record linkage study of mortality for a large cohort of opioid users ascertained by drug treatment or criminal justice sources in England, 2005–2009’ Drug & Alcohol Dependence, 146, 17-23