Frequent emergency department (ED) users are inconsistently defined and poorly studied in Canada. The purpose of this study was to develop uniform definitions, quantify ED burden, and characterize adult frequent users of a suburban community ED.

We retrospectively reviewed the administrative database of the WestView ED in Alberta for patients ≥ 18 years of age presenting during the fiscal year of 2010. Adult frequent users and extreme frequent users were defined as patients with yearly visit numbers greater than the 95th and 99th percentiles, respectively. Demographic information including age, sex, ED length of stay, diagnoses, Canadian Triage and Acuity Scale (CTAS) level, and disposition were collected and stratified by ED frequency of use categories.

The study included 22,333 ED visits by 14,223 patients. Frequent users represented 3.1% of patients and 13.8% of visits. Extreme frequent users represented 0.8% of patients, 5.4% of visits, and 568,879 cumulative ED minutes (395 days). Nonfrequent users had one to four, frequent users had five or more, and extreme frequent users had eight or more visits over a 12-month period. Frequent users and extreme frequent users had a significantly longer ED length of stay overall and in most age categories. Alcohol-related behavioural disorders, anxiety, nausea/vomiting, and chronic obstructive pulmonary disease were prominent diagnoses, suggesting that psychiatric, somatic, and chronic illnesses may underlie recurrent visits. Admission rates were significantly higher for frequent compared to nonfrequent users.

We propose reproducible definitions for adult frequent and extreme frequent ED users and provide information on the characteristics and burden of care of these groups at a community Canadian suburban ED. Adoption of these definitions would allow comparison across centres in future research and facilitate targeted interventions for frequent and extreme frequent ED users.