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

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.