Abstract. Objectives: To determine how the demographic, clinical, and utilization characteristics of emergency department (ED) frequent users differ from those of other ED patients. Methods: A crosssectional and retrospective cohort study was performed using a database of all 348,858 visits to the San Francisco General Hospital ED during a fiveyear period (July 1, 1993, to June 30, 1998. A ''frequent user'' visited the ED five or more times in a 12-month period. Results: Frequent users constituted 3.9% of ED patients but accounted for 20.5% of ED visits. The relative risk (RR) of frequent use was high among patients who were homeless (RR = 4.5), African American (RR = 1.8), and Medi-Cal sponsored (RR = 2.1). Frequent users were more likely to be seen for alcohol withdrawal (RR = 4.4), alcohol dependence (RR = 3.4), and alcohol intoxication (RR = 2.4). Frequent users were also more likely to visit for exacerbations of chronic conditions, including sickle cell anemia (RR = 8.0), renal failure (RR = 3.6), and chronic obstructive pulmonary disease (RR = 3.3). They were less likely to visit for all forms of trauma (RR = 0.43). Survival analysis showed that only 38% of frequent users for one year remained frequent users the next year. However, 56% of frequent users for two consecutive years remained frequent users in the third year. Conclusions: Frequent use of the ED reflects the urban social problems of homelessness, poverty, alcohol abuse, and chronic illness. Frequent use of the ED shows a high rate of decline from one year to the next. This rate of decline slows after the first year and suggests the existence of a smaller group of chronic frequent users. Key words: frequent users; emergency department. ACADEMIC EMER-GENCY MEDICINE 2000; 7:637-646 I N MOST emergency departments (EDs), a small group of frequent users accounts for a significant proportion of patient visits. It is commonly argued that maintaining ED capacity to care for frequent users is wasteful, that caring for frequent users detracts from the care of other ED patients, and most importantly, that the special needs of frequent users are not appropriately addressed in the ED.1-13 Emergency department frequent users have been characterized as disproportionately poor, male, members of minority groups, chronically ill, psychiatrically ill, alcoholic, and socially isolated. [1][2][3][4][5]7,14 The perceived problem of ED frequent use has prompted multiple proposed solutions. Any strategy to address frequent use of the ED requires a sound understanding of the problem. This report presents a demographic, clinical, and use-pattern comparison of ED frequent users with other ED patients based on a five-year database of all ED visits to an urban, public hospital. METHODSStudy Design. This descriptive, cross-sectional and cohort study compared frequent users with other ED patients using a database of ED visits containing patient-specific demographic information and visit-specific clinical and utilization information. This database was created and maintained ...