Between 1997 and 2007, the annual number of emergency department (ED) visits increased by 23 percent1. As visits to the ED rise, policymakers are increasingly concerned about the potential cost, quality, and long-term health and health care system consequences of ED overcrowding, overuse, and inappropriate use.
This Statistical Brief presents nationally representative data from the Healthcare Cost and Utilization Project (HCUP) on ED visits for adults, ages 18 years and older. The information focuses on the reasons why people visited the ED in 2008. Variations in ED visits based on demographic characteristics, discharge status, and expected payer are also discussed. All differences between estimates noted in the text are statistically significant at the 0.05 level or better.
- In 2008, there were about 124.9 million visits to the ED. More than three-quarters of these visits—over 98.5 million—were for adults ages 18 years and older.
- Rates of ED visits were 26 percent higher for women than men, 24 to 60 percent higher for adults 65 years and older than for younger adults, 90 percent higher for those from the lowest income areas than for those from the highest, and 39 percent higher for those from rural areas than for those from urban areas.
- ED visits for adults were billed most frequently to private payers (33.1 percent) followed by Medicare (25.9 percent), uninsured (19.6 percent), and Medicaid (16.1 percent).
- Injuries were related to nearly one-quarter of all ED visits for adults (22.7 percent).
- Over 9 in 10 ED visits were related to acute conditions. Half of these visits also involved chronic conditions. Injuries and abdominal pain were among the most frequent acute conditions seen in the ED, while cardiac conditions and diabetes were among the most frequent chronic conditions seen in the ED.
In 2008, there were over 98.5 million ED visits for adults ages 18 and older (table 1). This represents more than three-quarters (78.8 percent) of the 124.9 million ED visits in the US. Four out of five ED visits for adults were “treat-and-release” in which the patient was released from the ED rather than being admitted to that hospital for further care. However, a substantial portion of ED visits (18.5 percent) resulted in hospital admission.
Rates of ED visits varied by demographic characteristics with rates highest among women, individuals 65 years and older, those from the lowest income areas, and rural areas (figures 1 and 2). Overall ED utilization rates were 26 percent higher for women than men (476.5 visits per 1,000 women versus 377.6 visits per 1,000 men); 24 and 60 percent higher for adults 65 years and older than those 18–44 years and 45–64 years, respectively (550.0 visits per 1,000 65+ year olds versus 444.3 per 1,000 18–44 year olds and 344.8 per 1,000 45–64 year olds); 90 percent higher for adults from the lowest income areas than those from the highest income areas (543.9 per 1,000 adults versus 286.8 per 1,000 adults, respectively); and 39 percent higher for adults from rural areas than for those from urban areas (514.8 per 1,000 adults versus 371.5 per 1,000 adults, respectively). Many of these differences were still evident when treat-and-release ED visits and ED visits resulting in admission were examined separately.
In terms of primary expected payer (table 1), about one-third of ED visits were billed to private insurance (33.1 percent) followed by Medicare (25.9 percent), uninsured (19.6 percent) and Medicaid (16.1 percent). Among treat-and-release ED visits, 35.3 percent were billed to private insurance followed by uninsured (22.3 percent), Medicare (19.8 percent) and Medicaid (16.9 percent). For ED visits resulting in hospital admission, more than half were billed to Medicare (52.9 percent), nearly a quarter to private insurance (23.7 percent), over a tenth to Medicaid (12.7 percent) and only 7.6 percent were billed as uninsured.
Most common all-listed reasons for ED visits among adults
Figure 3 shows the reasons for ED visits, organized by body system, based on all-listed diagnoses. Injuries were the most common reason for all ED visits, comprising 22.7 percent of all ED visits. Respiratory and circulatory disorders were the next most common category of conditions: 12.9 percent and 12.7 percent of all ED visits, respectively. Ill-defined signs and symptoms, digestive disorders, and nervous system disorders each comprised roughly 10 percent of all ED visits.
The proportion of visits related to each condition varied by the type of ED visit. For example, circulatory disorders were seen in only 7.5 percent of treat-and-release ED visits, while among those ED visits resulting in hospital admission, 35.6 percent were for circulatory disorders. The most common conditions for treat-and-release ED visits included injuries (24.1 percent), ill-defined signs and symptoms (11.3 percent), and respiratory conditions (11.0 percent). The most common conditions for ED visits resulting in hospital admission included circulatory disorders (35.6 percent), digestive disorders (22.1 percent), respiratory disorders (21.5 percent), genitourinary disorders (16.3 percent), injuries (16.2 percent) and mental health and substance abuse conditions (13.0 percent).
Most common specific conditions
Figure 4 shows that the majority of ED visits were for patients with acute conditions (93.3 percent—44.7 percent involved only acute conditions and 48.6 percent involved both acute and chronic conditions). Although the majority of treat-and-release ED visits and those resulting in hospital admission involved acute conditions, the distribution of visits associated with acute and chronic conditions varied by type of visit. Both acute and chronic conditions were seen in only 39.4 percent of treat-and-release ED visits, while 89.2 percent of ED visits resulting in hospital admission were related to both types of conditions. Only 6 percent of ED visits resulting in hospital admission were related solely to acute conditions. A remarkably small proportion of all ED visits—6.7 percent—were related solely to exacerbations of chronic conditions, which are potentially preventable with appropriate outpatient care.
Table 2 provides details on the most frequent reasons for ED visits. These conditions accounted for approximately 52 percent of all ED visits, 53 percent of all treat-and-release ED visits, and 82 percent of ED visits resulting in hospital admission. Essential hypertension, a chronic condition, was the top most common condition for ED visits, being related to nearly 20 million (19.8 percent) ED visits. This was followed by several other chronic conditions including coronary atherosclerosis (11.9 percent), diabetes mellitus without complications (9.3 percent), and hyperlipidemia (8.0 percent). Top 10 specific reasons for ED visits also included acute conditions such as fluid and electolyte disorders (8.8 percent), superficial injury (8.7 percent), abdominal pain (7.4 percent), and sprains and strains (7.2 percent). Dominated by acute conditions, the top 3 common conditions for treat-and-release ED visits were essential hypertension (14.9 percent), superficial injury (10.0 percent), and sprains and strains (8.7 percent). The top 3 common conditions for ED visits resulting in hospital admission included two chronic conditions—coronary atherosclerosis (42.6 percent) and essential hypertension (41.1 percent) followed by an acute condition—fluid and electrolyte disorders (35.4 percent).
The estimates in this Statistical Brief are based upon data from the HCUP 2008 Nationwide Emergency Department Sample (NEDS). Population estimates were obtained from the US Census Bureau, Population Division, Table 2. Annual Estimates of the Resident Population by Sex and Selected Age Groups for the United States: April 1, 2000 to July 1, 2009 (NC-EST2009-02) as well as Claritas Population Estimates, 2008. Many of the statistics can also be generated from HCUPnet, a free, online query system that provides users with immediate access to the largest set of publicly available, all-payer national, regional, and State-level hospital care databases from HCUP.
Types of hospitals included in HCUP
HCUP is based on data from community hospitals, defined as short-term, non-Federal, general and other hospitals, excluding hospital units of other institutions (e.g., prisons). HCUP data include OB-GYN, ENT, orthopedic, cancer, pediatric, public, and academic medical hospitals. They exclude long-term care, rehabilitation, psychiatric, and alcoholism and chemical dependency hospitals, but these types of ED visits are included if they are from community hospitals.
Unit of analysis
The unit of analysis is the ED visit, not a person or patient. This means that a person who visits the ED multiple times in one year will be counted each time as a separate ED visit.
Treat-and-release ED visits
Treat-and-release ED visits were those ED visits in which patients are treated and released from that ED (i.e., they are not admitted to that specific hospital). While the majority of treat-and-release patients (93.7%) were discharged home, some were transferred to another acute care facility (1.7%), left against medical advice (1.7%), went to another type of long-term or intermediate care facility (nursing home or psychiatric treatment facility) (1.6%), referred to home health care (0.2%) or died (0.2%), or discharged alive but the destination is unknown (0.9%).
ED visits resulting in hospital admission
ED visits resulting in a hospital stay included those patients initially seen in the ED and then admitted to the same hospital.
Urban-rural location of patient residence
Urban-rural location is one of six categories as defined by the National Center for Health Statistics:
- Large Central Metropolitan: Central counties of metropolitan areas with a population of 1 million or greater
- Large Fringe Metropolitan: Fringe counties of counties of metropolitan areas with a population of 1 million or greater
- Medium Metropolitan: Counties in metro area of 250,000–999,999 population
- Small Metropolitan: Counties in metro areas of 50,000–249,999 population
- Micropolitan: Micropolitan counties, i.e. a non-metropolitan county with an area of 10,000 or more population
- Non-core: Non-metropolitan and non-micropolitan counties
These six categories are aggregated into four groups, including urban (large central metropolitan), suburban (large fringe metropolitan), medium and small metropolitan and rural (micropolitan and non-core areas).
Median community-level income
Median community-level income is the median household income of the patient’s ZIP Code of residence. The cut-offs for the quartile designation are determined using ZIP Code demographic data obtained from Claritas. The income quartile is missing for homeless and foreign patients.
Payer is the primary expected payer for the ED visit. To make coding uniform across all HCUP data sources, payer combines detailed categories into more general groups:
Medicare includes fee-for-service and managed care. Medicare is a Health Insurance Program for people age 65 or older, some disabled people under age 65 (social security disability insurance), and people of all ages with End-Stage Renal Disease (permanent kidney failure treated with dialysis or a transplant).
Medicaid includes fee-for-service and managed care Medicaid patients.
Private insurance includes Blue Cross, commercial carriers, and private HMOs and PPOs.
Other includes Workers’ Compensation, TRICARE/CHAMPUS, CHAMPVA, Title V, and other government programs.
Uninsured includes an insurance status of “self-pay” and “no charge.”
When more than one payer is listed for a hospital discharge, the first-listed payer is used.
Diagnoses, ICD-9-CM, and Clinical Classifications Software (CCS)
The principal diagnosis is that condition established after study to be chiefly responsible for the patient’s admission to the hospital. Secondary diagnoses are concomitant conditions that coexist at the time of admission or that develop during the stay. All-listed diagnoses include the principal diagnosis plus these additional secondary conditions.
ICD-9-CM is the International Classification of Diseases, Ninth Revision, Clinical Modification, which assigns numeric codes to diagnoses. There are about 13,600 ICD-9-CM diagnosis codes.
CCS categorizes ICD-9-CM diagnoses and procedures into clinically meaningful categories.2 This “clinical grouper” makes it easier to quickly understand patterns of diagnoses and procedures.
A chronic condition is defined as a condition that lasts 12 months or longer and meets one or both of the following tests: (a) it places limitations on self-care, independent living, and social interactions; (b) it results in the need for ongoing intervention with medical products, services, and special equipment. The identification of chronic conditions is based on all 5-digit ICD-9-CM codes. E Codes, or external cause of injury codes, are not classified because all injuries are assumed to be acute. Additional information on the Chronic Condition Indicator (CCI) HCUP tool can be found at http://www.hcup-us.ahrq.gov/toolssoftware/chronic/chronic.jsp.
ED visits were further classified as having only chronic conditions listed, only acute conditions listed or both chronic and acute conditions listed on the record.
For More Information
For more information about HCUP, visit www.hcup-us.ahrq.gov.
For additional HCUP statistics, visit HCUPnet, our interactive query system, at www.hcup.ahrq.gov.
For information on hospitalizations in the U.S., download HCUP Facts and Figures: Statistics on Hospital-based Care in the United States in 2008, located at http://www.hcup-us.ahrq.gov/reports.jsp.
For a detailed description of HCUP, more information on the design of the NEDS, and methods to calculate estimates, please refer to the following publications:
Steiner, C., Elixhauser, A., Schnaier, J. The Healthcare Cost and Utilization Project: An Overview. Effective Clinical Practice 2002;5(3):143–51.
Introduction to the HCUP Nationwide Emergency Department Sample, 2008. Online. January, 2010. U.S. Agency for Healthcare Research and Quality. http://www.hcup-us.ahrq.gov/db/nation/neds/NEDS2008Introductionv3.pdf
Houchens, R., Elixhauser, A. Final Report on Calculating Nationwide Inpatient Sample (NIS) Variances, 2001. HCUP Methods Series Report #2003-2. Online. June 2005 (revised June 6, 2005). U.S. Agency for Healthcare Research and Quality. http://www.hcup-us.ahrq.gov/reports/CalculatingNISVariances200106092005.pdf
Niska R, Bhuiya F, Xu J. National Hospital Ambulatory Medical Care Survey: 2007 Emergency Department Summary. National Health Statistics Reports: No. 26. Hyattsville, MD: National Center for Health Statistics. 2010.
Note: Overall ED visit rate
Note: Overall ED visit rate
HCUP CCS. Healthcare Cost and Utilization Project (HCUP). December 2009. U.S. Agency for Healthcare Research and Quality, Rockville, MD. www
Owens P.L., Mutter R. Emergency Department Visits Abuse for Adults in Community Hospitals, 2008. HCUP Statistical Brief #100. November 2010. Agency for Healthcare Research and Quality, Rockville, MD. http://www
About the NEDS: The HCUP Nationwide Emergency Department Database (NEDS) is a unique and powerful database that yields national estimates of emergency department (ED) visits. The NEDS was constructed using records from both the HCUP State Emergency Department Databases (SEDD) and the State Inpatient Databases (SID). The SEDD capture information on ED visits that do not result in an admission (i.e., treat-and-release visits and transfers to another hospital); the SID contain information on patients initially seen in the emergency room and then admitted to the same hospital. The NEDS was created to enable analyses of ED utilization patterns and support public health professionals, administrators, policymakers, and clinicians in their decision-making regarding this critical source of care.
About HCUPnet: HCUPnet is an online query system that offers instant access to the largest set of all-payer health care databases that are publicly available. HCUPnet has an easy step-by-step query system, allowing for tables and graphs to be generated on national and regional statistics, as well as trends for community hospitals in the U.S. HCUPnet generates statistics using data from HCUP's Nationwide Inpatient Sample (NIS), the Kids' Inpatient Database (KID), the Nationwide Emergency Department Sample (NEDS), the State Inpatient Databases (SID) and the State Emergency Department Databases (SEDD).
Pamela L Owens, PhD and Ryan Mutter, PhD.
Published: November 2010.
Agency for Health Care Policy and Research (US), Rockville (MD)
Owens PL, Mutter R. Emergency Department Visits for Adults in Community Hospitals, 2008: Statistical Brief #100. 2010 Nov. In: Healthcare Cost and Utilization Project (HCUP) Statistical Briefs [Internet]. Rockville (MD): Agency for Health Care Policy and Research (US); 2006 Feb-.