Are People Who Inject Drugs Frequent Users of Emergency Department Services? A Cohort Study (2008–2013)

ABSTRACT

Background: Although people who inject drugs (PWID) have been described as frequent users of emergency services, the majority of research is cross-sectional and involves records from a single emergency department (ED). Objectives: We describe characteristics of state-wide ED presentations in a cohort of PWID, and compare presentation rates to the general population. We also examine characteristics associated with frequent ED use. Methods: We used data from a retrospective linkage of public ED presentations from a cohort of 678 PWID between January 2008 and June 2013. Common principal diagnoses were described using the International Classification of Diseases, Tenth Revision, Australian Modification (ICD-10-AM) chapter headings. The ED presentation trend was estimated using negative-binomial regression. Characteristics associated with frequent use of EDs were identified using generalized estimating equations (GEEs). Results: There were 3437 presentations over 4163.5 person-years (PY) and the most common principal diagnosis was injury, poisoning and other externalities (19%). ED presentations increased by 4% every six months (95% confidence interval (CI) 0.1%–0.8%) and were three times greater than the general population. A quarter (24%) of the cohort presented frequently, and they were more likely to have noninjury-related diagnoses and be aged below 30 years, and less likely to have nonurgent presentations and be male. Conclusions: PWID use EDs at a higher rate than the general population, and typically present with injuries and mental and behavioral disorders. Referrals to drug treatment, mental health, and social support services can improve patient care and reduce the burden on EDs.

KEYWORDS:

• Australia
• cohort
• emergency service
• health resources
• hospital
• injecting drug use
• longitudinal studies

Acknowledgments

The authors thank study participants, interviewers, and organizations involved in the recruitment. We thank Simon Brown, Katy Greenland, Ying Chen, Likhesh Mahajan, and Pradeep Wijayaratne from the Department of Health and Human Services for extracting the data. We also thank Dr. Helen Ackland of the Alfred hospital and Kate Cantwell of Ambulance Victoria who were consulted regarding risk factors for frequent ED presentations.

Funding

The MIX study is funded by The Colonial Foundation Trust and the National Health and Medical Research Council (NHMRC Grant #545891). D. Nambiar receives support from the National Health and Medical Research Council (NHMRC) through a postgraduate scholarship awarded through the Burnet Institute Centre for Research Excellence into Injecting Drug Use (CREIDU—APP1001144). P. Dietze is an NHMRC Senior Research Fellow and M. Stoové is an NHMRC Career Development Fellow and receives support through CREIDU. The authors gratefully acknowledge the contribution to this work of the Victorian Operational Infrastructure Support Program. The funding bodies played no role in the study design, data analysis, or preparation of the manuscript for publication.