Compare clinical characteristics for adult visits to freestanding emergency departments (FEDs) and a hospital-based ED (HBED).

Electronic health records were collected on adult ED visits from 7/1/14 to 6/30/15 from three FEDs and one level 1 trauma tertiary care HBED.

There were 55,909 HBED visits; 44,108 FED visits. The FED population was slightly more female (61% vs 57%), younger (48 vs 46 years), white (86% vs 60%), and employed (67% vs 49%). A higher percent of FED visits had private insurance (43% vs 20%); a lower percent had Medicaid (25% vs 42%) and Medicare (23% vs 30%). The top three presenting problems were the same at the HBED and FEDs, but the order differed: gastrointestinal (HBED 19% vs FED 18%), cardiorespiratory (18% vs 16%), injury-pain-swelling of extremity (14% vs 17%). Differences were seen in primary ICD9 codes. One quarter of FED visits and only 18% of HBED visits were for injury/poisoning. A higher percent of FED visits were for respiratory diseases (12% vs 9%) but a lower percent were for circulatory system diseases (7% vs 11%) and visits for mental illness (2% vs 6%). Nearly 30% of HBED visits resulted in admission, compared to 8% of FED visits. ESI level differed significantly, with a lower percent of high acuity cases at FEDs (level 1: 0.1% vs 1.6%; level 2: 5% vs 26%).

Differences were observed in clinical characteristics of adult HBED visits versus FEDs. Results of this study can help communities plan their emergency care system.