Mortality among opioid dependent persons in pharmacotherapy, NSW 1985-2006
NDARC Staff
Louisa Degenhardt, Lucy Burns, Deborah Randall, Amy Gibson and Richard Mattick
Other Investigators
Wayne Hall (School of Population Health, University of Queensland), Matthew Law (National Centre in HIV Epidemiology and Clinical Research, UNSW), Tony Butler (National Drug Research Institute, Curtin University of Technology) and Janaki Amin (Justice Health, NSW Health)
Aims
The aims of this project are to:
- examine overall mortality rates of persons enrolled in NSW opioid maintenance treatment (methadone or buprenorphine) between 1985 and 2006
- examine possible changes in both the rates and causes of mortality over this period
- examine the rates and causes of mortality according to factors such as age and gender
- examine the impact of opioid maintenance treatment on rates and causes of mortality among this cohort
Design and Method
The study involves an historical cohort linking identified individuals in existing datasets on opioid maintenance treatment and mortality. All people who commenced an episode of methadone or buprenorphine treatment in NSW between 1985 and 2006 (approximately 45,000 people) have been included in the study. Data on all patients entering methadone or buprenorphine treatment since 1985 are kept by NSW Health; these data have been linked to mortality and causes of death data managed by the Australian Institute of Health and Welfare.
Predictors of mortality have been examined using Poisson regression, stratified according to the different causes of death. Other analyses include: predictors of treatment retention, analysed using survival analysis; whether the incidence of any causes of death have changed over time; and how treatment exposure has impacted on mortality rates.
Progress
- Ethics approval obtained from the Department of Health and University of New South Wales ethics committees.
- Professional Research Person (PRP) employed in August 2007.
- The Pharmaceutical Drugs of Addiction System (PHDAS) data has been successfully linked to the National Death Index by AIHW, including clerical review by the PRP.
- Extensive data cleaning and preparation has been done on the linked data, including auditing against PHDAS hard copy files.
- Analysis conducted on the predictors of length of time in the first treatment program, overall mortality rates over time, causes of mortality, and risk of death in treatment and out of treatment.
- Further papers being prepared on cause-specific mortality rates over time and other topics.
Output
- Burns, L., Randall, D., Hall, W.D., Law, M., Butler, T., Bell, J. & Degenhardt, L. (2009), Opioid agonist pharmacotherapy in New South Wales from 1985 to 2006: patient characteristics and patterns and predictors of treatment retention, Addiction, 104, 1363-1372.
- Degenhardt, L., Randall, D., Hall, W., Law, M., Butler, T., & Burns, L. (in press), Mortality among clients of a State-wide opioid pharmacotherapy program over 20 years: Risk factors and lives saved, Drug and Alcohol Dependence.
- Degenhardt, L. (2008). Opioid pharmacotherapy and mortality in New South Wales from 1985 to 2006: Rates, patterns, and risk both in and out of treatment. Oral presentation at the APSAD Conference, Sydney, Australia.
- Two poster presentations at APSAD, one on characteristics and patterns of treatment retention, and one on cause-specific mortality over time.
Funding
National Health and Medical Research Council