Characteristics of frequent users of emergency departments in Alberta and Ontario, Canada: an administrative data study

Objective Frequent users to emergency departments (EDs) are a diverse group of patients accounting for a disproportionate number of ED presentations. This study examined sociodemographic and ED visit characteristics of adult high-system users in two Canadian provinces. Methods Cohorts of high-system users were created for Alberta and Ontario including patients with the top 10% of presentations in the National Ambulatory Care Reporting System (April 2015-March 2016). Controls were random samples of non-high-system user patients. Sociodemographic and ED visits data were used to predict high-system user group membership in a multivariable logistic regression model. Results There were 579,674 high-system users and 2,115,960 controls. High-system users were more likely to be female [odds ratio (OR) = 1.1, 95% confidence interval (CI) 1.1,1.1], older (OR 1.02 per 5 years, 95% CI 1.02,1.02), from the lowest-income quintile (OR 1.8, 95% CI 1.7,1.8), and more rural (OR 1.6, 95% CI 1.6,1.6) than controls. High-system users had a higher proportion of presentations by ambulance (OR 1.1 per 0.25 increase, 95% CI 1.1,1.1) and disposition was admission/transfer (OR 1.1 per 0.25 increase, 95% CI 1.1,1.1), left without being seen (OR 1.1, 95% CI 1.1,1.1), or left against medical advice (OR 1.1, 95% CI 1.1,1.1) more often than controls. Conclusion High-system users were more likely to be female, older, live in rural areas and within the lowest-income quintile compared to controls. Their heterogeneity in acuity, comorbid chronic diseases, and limited access to primary care suggests that interventions referring high-system users to primary care may be fruitful in reducing ED utilization by high-system users.