The Evolving Role of Emergency Departments in the United States

Emergency departments (EDs) emerged with the rise of hospital-based medicine in the aftermath of World War II. Today, they play a pivotal role in the delivery of acute ambulatory and inpatient care. As our health care system evolves in response to economic, clinical, and political pressures, the role of EDs is evolving as well.

Because EDs charge higher prices for minor illness and injury care than other ambulatory care settings, ED care is frequently characterized as “the most expensive care there is.” But this depiction ignores the many roles that EDs fill, and the statutory obligation of hospital EDs to provide care to all in need without regard for their ability to pay. To develop a more complete picture of how EDs contribute to our modern health care system, the Emergency Medicine Action Fund asked RAND to conduct this mixed-methods study.

At the outset of our effort, we reviewed recently published literature regarding ED use and used it to craft a conceptual model that depicts the various choices ED patients and providers make over the course of an episode of care. To quantify the importance of EDs as a major portal of entry to inpatient care, we analyzed four datasets compiled and maintained by the U.S. Department of Health and Human Services. Given a growing focus at the national and state levels on preventing non-urgent patients from seeking care in EDs, we analyzed data from the Community Tracking Study, a decade-long effort that describes changing patterns of health care utilization and delivery in 60 communities nationwide. To add context to the quantitative observations derived from these analyses, we conducted three focus groups with emergency medicine and hospitalist physicians, and interviewed 16 practicing primary care physicians who work in a variety of communities.

Key findings include the following:

• Between 2003 and 2009, inpatient admissions to U.S. hospitals grew at a slower rate than the population overall. However, nearly all of the growth in admissions was due to a 17 percent increase in unscheduled inpatient admissions from EDs. This growth in ED admissions more than offset a 10 percent decrease in admissions from doctors' offices and other outpatient settings. This pattern suggests that office-based physicians are directing to EDs some of the patients they previously admitted to the hospital.
• In addition to serving as an increasingly important portal of hospital admissions, EDs support primary care practices by performing complex diagnostic workups and handling overflow, after-hours, and weekend demand for care. Almost all of the physicians we interviewed—specialist and primary care alike—confirmed that office-based physicians increasingly rely on EDs to evaluate complex patients with potentially serious problems, rather than managing these patients themselves.
• As a result of these shifts in practice, emergency physicians are increasingly serving as the major decisionmaker for approximately half of all hospital admissions in the United States. This role has important financial implications, not only because admissions generate the bulk of facility revenue for hospitals, but also because inpatient care accounts for 31 percent of national health care spending.
• Although the core role of EDs is to evaluate and stabilize seriously ill and injured patients, the vast majority of patients who seek care in an ED walk in the front door and leave the same way. Data from the Community Tracking Study indicate that most ambulatory patients do not use EDs for the sake of convenience. Rather, they seek care in EDs because they perceive no viable alternative exists, or because a health care provider sent them there.
• Medicare accounts for more inpatient admissions from EDs than any other payer. To gain insight into whether care coordination makes a difference in the likelihood of hospital admission from an ED, we compared ED admission rates among Medicare beneficiaries enrolled in a Medicare Choice plan versus beneficiaries enrolled in Medicare fee-for-service (FFS). We found no clear effect on inpatient admissions overall, or on a subset of admissions involving conditions that might be considered “judgment calls.”
• Irrespective of the impact of care coordination, EDs may be playing a constructive role in constraining the growth of inpatient admissions. Although the number of non-elective ED admissions has increased substantially over the past decade, inpatient admissions of ED patients with “potentially preventable admissions” (as defined by the Agency for Healthcare Research and Quality) are flat over this time interval.

Our study indicates that: (1) EDs have become an important source of admissions for American hospitals; (2) EDs are being used with increasing frequency to conduct complex diagnostic workups of patients with worrisome symptoms; (3) Despite recent efforts to strengthen primary care, the principal reason patients visit EDs for non-emergent outpatient care is lack of timely options elsewhere; and (4) EDs may be playing a constructive role in preventing some hospital admissions, particularly those involving patients with an ambulatory care sensitive condition. Policymakers, third party payers, and the public should be aware of the various ways EDs meet the health care needs of the communities they serve and support the efforts of ED providers to more effectively integrate ED operations into both inpatient and outpatient care.

The research described in this article was sponsored by the Emergency Medicine Action Fund, a consortium sponsored by the American College of Emergency Physicians. The work was conducted in RAND Health, a division of the RAND Corporation.