Characteristics of frequent emergency department users in British Columbia, Canada: a retrospective analysis.

BACKGROUND:Frequent emergency department users disproportionately account for rising health care costs. We aimed to characterize frequent emergency department users in British Columbia, Canada. METHODS:We performed a retrospective analysis using health administrative databases. We included patients aged 18 years or more with at least 1 emergency department visit from 2012/13 to 2015/16, linked to hospital, physician billing, prescription and mortality data. We used annual emergency department visits made by the top 10% of patients to define frequent users (≥ 3 visits/year). RESULTS:Over the study period, 13.8%-15.3% of patients seen in emergency departments were frequent users. We identified 205 136 frequent users among 1 196 353 emergency department visitors. Frequent users made 40.3% of total visits in 2015/16. From 2012/13 to 2015/16, their visit rates per 100 000 BC population showed a relative increase of 21.8%, versus 13.1% among all emergency department patients. Only 1.8% were frequent users in all study years. Mental illness accounted for 8.2% of visits among those less than 60 years of age, and circulatory or respiratory diagnoses for 13.3% of visits among those aged 60 or more. In 2015/16, frequent users were older and had lower household incomes than nonfrequent users; the sex distribution was similar. Frequent users had more prescriptions (median 9, interquartile range [IQR] 5-14 v. 1, IQR 1-3), primary care visits (median 15, IQR 9-27 v. 7, IQR 4-12) and hospital admissions (median 2, IQR 1-3 v. 1, IQR 1-1), and higher 1-year mortality (10.2% v. 3.5%) than nonfrequent users. INTERPRETATION:Emergency department use by frequent users increased in BC between 2012/13 and 2015/16; these patients were heterogenous, had high mortality and rarely remained frequent users over multiple years. Our results suggest that interventions must account for heterogeneity and address triggers of frequent use episodes.