Survival and cessation in injecting drug users: prospective observational study of outcomes and effect of opiate substitution treatment
BMJ 2010; 341 doi: https://doi.org/10.1136/bmj.c3172 (Published 01 July 2010) Cite this as: BMJ 2010;341:c3172
- Jo Kimber, NHMRC postdoctoral fellow12,
- Lorraine Copeland, researcher3,
- Matthew Hickman, professor in public health and epidemiology1,
- John Macleod, professor in clinical epidemiology and primary care2,
- James McKenzie, research community psychiatry nurse3,
- Daniela De Angelis, senior statistician45,
- James Roy Robertson, reader and general practice principal36
- 1Department of Social Medicine, University of Bristol, Bristol BS8 2PS
- 2National Centre in HIV Epidemiology and Clinical Research, University of New South Wales, Sydney 2052, Australia
- 3Muirhouse Medical Group, Edinburgh EH4 4P
- 4MRC Biostatistics Unit, Institute of Public Health, University of Cambridge
- 5Health Protection Agency, Centre for Infections, London
- 6Division of Community Health Sciences, University of Edinburgh, Edinburgh EH8 9AG
- Correspondence to: M Hickman matthew.hickman{at}bristol.ac.uk
- Accepted 13 April 2010
Abstract
Objectives To examine survival and long term cessation of injecting in a cohort of drug users and to assess the influence of opiate substitution treatment on these outcomes.
Design Prospective open cohort study.
Setting A single primary care facility in Edinburgh.
Participants 794 patients with a history of injecting drug use presenting between 1980 and 2007; 655 (82%) were followed up by interview or linkage to primary care records and mortality register, or both, and contributed 10 390 person years at risk; 557 (85%) had received opiate substitution treatment.
Main outcome measures Duration of injecting: years from first injection to long term cessation, defined as last injection before period of five years of non-injecting; mortality before cessation; overall survival.
Results In the entire cohort 277 participants achieved long term cessation of injecting, and 228 died. Half of the survivors had poor health related quality of life. Median duration from first injection to death was 24 years for participants with HIV and 41 years for those without HIV. For each additional year of opiate substitution treatment the hazard of death before long term cessation fell 13% (95% confidence interval 17% to 9%) after adjustment for HIV, sex, calendar period, age at first injection, and history of prison and overdose. Conversely exposure to opiate substitution treatment was inversely related to the chances of achieving long term cessation.
Conclusions Opiate substitution treatment in injecting drug users in primary care reduces this risk of mortality, with survival benefits increasing with cumulative exposure to treatment. Treatment does not reduce the overall duration of injecting.
Footnotes
We gratefully acknowledge the provision of data from the Scottish Prison Service (Jim Carney), Lothian and Borders Police Force, the General Register Office for Scotland, and Information Services Division of the Scottish Government and the daily support and accommodation of the study by the partners and staff of the Muirhouse Medical Group.
Contributors: JRR is principal investigator of the Edinburgh Addiction Study. MH, JM, and JRR conceived the present follow-up study and obtained funding. LC and JMcK undertook the fieldwork. DDA oversaw the analytic strategy with JK and MH. LC assembled the dataset, organised the contact tracing and external sources, and transposed case records into the dataset and managed the essential administration for the study. JK undertook data cleaning and descriptive analyses with LC, JK, MH, and DDA. JK wrote the first draft of the paper with all authors contributing to the final draft. JRR is study guarantor.
Funding: The present follow-up study of the Edinburgh Addiction Cohort was supported by the Chief Scientist Office for Scotland (CZH/4/318). At the time they undertook this work JM and MH were supported by career scientist fellowship awards from the National Institute of Health Research. JK is supported by an Australian National Health and Medical Research (NHMRC) postdoctoral training fellowship. The National Centre in HIV Epidemiology and Clinical Research is core-funded by the Australian Government Department of Health and Ageing. LC and JMcK were funded by the chief scientist office grant (CZH/4/318), with the latter being seconded to the study by the community drug problem service, (CDPS), Lothian. DDA is funded by Health Protection Agency and the Medical Research Council (grant No U.1052.00.007).
Competing interests: All authors have completed the Unified Competing Interest form at www.icmje.org/coi_disclosure.pdf (available on request from the corresponding author) and all authors want to declare (1) Financial support for the submitted work from Chief Scientist Office for Scotland (above). All authors also declare (2) No financial relationships with commercial entities that might have an interest in the submitted work; (3) No spouses, partners, or children with relationships with commercial entities that might have an interest in the submitted work; (4) No non-financial interests that may be relevant to the submitted work.
Ethical approval: This study was approved by Lothian health ethics committee (LREC/2003/7/12) and informed consent was given by all participants.
Data sharing: Data on the sensitivity analysis and further interview data are available from the corresponding author.
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