Hospital emergency departments vary greatly across country

New database reveals great diversity in patient volume, could help guide future planning efforts

A large percentage of hospital emergency departments across the U.S. are very different from the high-intensity setting familiar to viewers of the television program "ER." A database developed by a research team based at Massachusetts General Hospital – the first comprehensive list of emergency departments (EDs) across the country – shows that one-third of all EDs care for less than one patient each hour, on average. Based on information from 2001, the database is the first step in a process that may lead to the development of an ED classification system, similar to what currently exists for trauma centers. The creation of national standards for ED categorization was recommended in the 2006 Institute of Medicine report "The Future of Emergency Care in the U.S. Health System."

"Our results suggest that EDs are quite different from one another and that we may need to consider a variety of approaches to ensure access to emergency care for all Americans," says Ashley Sullivan, MS, MPH, of the MGH Department of Emergency Medicine, lead author of the report in the December Annals of Emergency Medicine.

The new database – known as the National ED Inventory (NEDI) – is a project of the Emergency Medicine Network (EMNet,, 180 medical centers that focus on public health research in emergency medicine. To conduct nationwide investigations of emergency services, the EMNet team needed an accurate, comprehensive listing of all EDs in the U.S. Combining material from two existing but conflicting databases, the team gathered additional information to characterize all US hospital facilities that were open 24 hours a day, 7 days a week, accessible to the general public and not limited to a particular specialty.

The information compiled on almost 4,900 hospitals revealed a wide range of patient visits per year. One third of EDs receive fewer than 8,760 visits a year – an average of less than one patient each hour. Higher volume facilities – which account for 94 percent of all visits nationwide – are concentrated in metropolitan areas, while most lower volume EDs are in rural settings.

While the Northeast had the fewest EDs, 89 percent of facilities in the region were higher volume. Higher volume EDs accounted for 72 percent of the facilities in the South, 66 percent in the West and only 55 percent of EDs in the Midwest. Regional patient visits per capita, which account for differences in population density, were highest in the South and lowest in the West. These differences could reflect factors such as patients’ need for ‘safety net’ medical services, the availability of community primary care physicians and the challenge of traveling long distances to reach the nearest ED, the research team notes.

"We were struck by the different visit volume of the average U.S. ED, which sees about 16,000 patients per year, compared to sites where future emergency physicians are trained, with average volumes of 49,000 visits per year," says Carlos Camargo Jr., MD, DrPH, of MGH-Emergency Medicine, director of EMNet and senior author of the Annals report. "We need to confirm that we are giving our emergency medicine residents the best training for future work in these smaller EDs. We also may want to re-examine other pathways to ensure continued emergency care in smaller EDs, which face many challenges in the recruitment and retention of physicians." Camargo is an associate professor of Medicine at Harvard Medical School.

The MGH-based group will be updating the NEDI every two years to monitor national trends; information has been gathered for 2003 and is currently being compiled for 2005. To broaden the type of data gathered for NEDI, the team will conduct additional surveys to examine likely differences among EDs regarding the types of conditions cared for, staffing and available consultants, and the availability of diagnostic and therapeutic services. They also have launched a pilot survey of EDs in Singapore that will be followed by similar surveys in other countries.

"We need to further examine the characteristics of EDs to better understand the landscape of emergency medicine in the U.S.," Sullivan says. "NEDI provides a way to better understand the literally thousands of smaller EDs that may be overlooked in the development and implementation of policy decisions affecting emergency medicine."


Additional co-authors of the Annals of Emergency Medicine report are Ilana Richman, Christina Ahn and Sunday Clark, MPH, ScD, of the MGH; Bruce Auerbach, MD, Sturdy Memorial Hospital, Attleboro, Mass.; Daniel Pallin, MD, MPH, Brigham and Women’s Hospital; and Robert Schafermeyer, MD, Carolinas Medical Center in Charlotte, N.C. The study was supported by an EMF Center of Excellence Award and a grant from the Agency for Healthcare Research and Quality.

Massachusetts General Hospital, established in 1811, is the original and largest teaching hospital of Harvard Medical School. The MGH conducts the largest hospital-based research program in the United States, with an annual research budget of nearly $500 million and major research centers in AIDS, cardiovascular research, cancer, computational and integrative biology, cutaneous biology, human genetics, medical imaging, neurodegenerative disorders, regenerative medicine, transplantation biology and photomedicine. MGH and Brigham and Women's Hospital are founding members of Partners HealthCare System, a Boston-based integrated health care delivery system.

Last reviewed: By John M. Grohol, Psy.D. on 30 Apr 2016
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