Befriending Big Data

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Never before have the cold, hard numbers behind emergency medicine been more accessible. Know how to access the data that will help your department anticipate new challenges.

“Data is my friend!”


A long time ago, a very smart hospital CFO made me say those words to him as we prepared for a meeting with the hospital’s Foundation Board. They were looking to find a project to fund with the contribution of a very generous community member. We delivered a very data-heavy presentation which developed a set of performance measures for our emergency department that convinced the board that the ED was making an impact on community care and the regional health system that could not be matched by a contribution anywhere else in the hospital. We developed some crude comparison measures to other EDs in the region and built a case that this very busy ED – which had just cracked the 100 patients per day average – was going to continue to grow in volume. Even the hospital CEO was skeptical that the ED could keep growing volume, because 40,000 patients per year was an enormous number, and only a few EDs in very large metropolitan areas were seeing those kinds of numbers.

altIt worked, and a month later, as I related the news to my physician colleagues that a new emergency department could be built based on the donation, my newfound love of data could hardly be contained. I knew then that emergency department numbers would never again put me to sleep.

Fast forward to today and emergency department leaders have great access to data, numbers that allow them to manage departments that routinely see 300 patients a day, and to plan for future needs of both patients and staff. There are two large data sources to consider. One focuses on patient populations using the ED and the trends related to their presentation complaints, treatment, and disposition. The other focuses on the performance of the ED, with measures designed to assist managers in understanding operations and predicting future challenges and department needs.


Patient-Focused Data
Most of our high quality patient-focused data is the product of The National Hospital Ambulatory Medical Care Survey (NHAMCS). Within the CDC, a group of scientists has been gathering, analyzing, and disseminating information about hospital outpatient and emergency departments since 1992. NHAMCS and the National Ambulatory Medical Care Survey (NAMCS) are parts of the ambulatory component of the National Health Care Surveys, a family of surveys that measure health care utilization across various types of providers.  

The emergency department elements of the NHAMCS are based on a sampling methodology that takes some time to compile and verify. Therefore the survey publication typically occurs about three years after the data collection year. The latest available report is for care provided in American EDs in the calendar year 2010, and is available on the CDC’s web site. The 2010 data report is based on a sampling of 34,936 ED patient care reports from 357 emergency departments. National population census data was used to estimate utilization of ED services by populations. The CDC data tables are now published without an analysis, and the data reported only in table form. Therefore, it will be important for ED leaders to archive the 2007 report, which was the last that was accompanied by a written analysis. (

The 2010 data tables are 33 pages in length, but they’re a surprisingly easy read. The survey now has 19 years of annual data. With this longevity, the survey has identified trends in the ED visits that are important for hospital and regulatory leaders to understand.

The 2010 report was the second year that the survey staff studied hospital operations and design, including the presence of hospital bed coordinators, the utilization of hospital bed census data, the presence of Clinical Decision (or Observation) Units, the use of electronic medical records, the prevalence of ED boarding and use of diversion, and the actual or planned expansion of ED clinical space. These elements are summarized in the last two pages of the data tables, and should not be overlooked in the review.


Over the history of the project, the leaders of the NHAMCS survey have been insightful in developing data that can address emergency care issues in a timely way. Data from the survey was brought to light in the ACEP 2009 National Report Card; the U.S. Government Accounting Office (GAO) report on ED Crowding; the Institute of Medicine (IOM) 2006 ED Report on on-call issues and pediatric care; and the U.S. Department of Health and Human Service Healthy People 2010 Report.

The NHAMCS data allowed the Government Accountability Office (GAO) to report that the main issue contributing to overcrowding of EDs has been delays in moving the sickest patients to inpatient beds. The boarding of admitted patients in EDs or hospital hallways for hours to days was linked to overcrowding and diversion of incoming ambulances to other hospitals. This report then allowed the IOM to recommend adopting systems to even out the flow of patient admissions and implement clinical decision units. So the NHAMCS data has given ED leaders the material to address hospital C-suites based on patient needs.

ED-Focused Data
The EDBA was founded in 1994, and is composed of ED administrators (physicians, nursing, and management) and dedicated applying of management and service concepts to improve the quality of emergency medical care, patient satisfaction, medical education, and community service. When it started, the EDBA was composed of ED leaders in large EDs, which at the time meant 100 patients per day. It is now an Alliance of 1,000 high performance American emergency departments that served over 37 million patients in the calendar year 2012. Those EDs are from every state, every volume and acuity. The EDBA does an annual data survey, which canvases the members for a small number of well-defined performance measures and descriptive elements of the ED. The Alliance format can produce more timely reports, so it has just published for its members the results of their collective operations for the calendar year 2012.

The Latest Results
Emergency department leaders need both ED performance and patient-focused data sets to plan for the immediate and future needs in design, staffing, and hospital support. Both surveys find that EDs are serving more senior patients, higher acuity patients, and more patients arriving by ambulance. The ED population is aging, in line with the demographics of the country. ED visits have increased over 12 years from 369 visits per 1000 population to 428 per thousand. Those persons over age 75 had 635 visits per 1000 population. For ED leaders, this indicates a need to prepare for larger numbers of patients, and have processes that are more friendly to the older population. This population group is not going to shrink for years, until the boomer population has passed.

Data Worth Celebrating
Emergency leaders have been very successful in their efforts in prevention. Over 40 years in the development of the modern American emergency system, there are few publications that herald the tremendous success in preventing morbidity and mortality from trauma, burns, and cardiac arrest. But in reviewing the data, it is apparent that prevention is working. ED visits related to injuries continue to shrink, and now represent about 29% of patient encounters. The biggest increase in injuries is occurring in the elderly.

The need for precision in defining patient needs has resulted in more use of diagnostic tools in the ED, especially EKGs. The use of CT scanning appears to have plateaued, but MRI, and other special imaging procedures like ultrasound, are increasing.

Matching the increase in acuity is the need for further hospital based service at the end of the ED visits. A growing percentage of hospital admissions are funneled through the ED. There are more patient transfers: 1.9% of all ED patients, or 2.9 million a year. The NHAMCS report is finding an increased number of patients seen for mental health reasons, and their disposition is often difficult and time consuming. About half of patient transfers from EDs are for mental health treatment. Overall, despite increased volumes, flow through the ED is improving. Patient lengths of stay in the ED appear to have peaked in 2008, and the number of patients that walk away from the ED before treatment is complete has decreased.

It is critical that emergency physicians and department leaders understand the data and trends in emergency care. More importantly, they need to be able to use the national data sources to improve the local emergency system and the ED practice site. This is the first of a series of columns that Emergency Physicians Monthly will publish regarding ED data and performance measures. Future columns will cover more results of the NHAMCS and EDBA surveys. These are practice-changing numbers that can result in immediate improvements in your department. Stay tuned.

Dr. Augustine is the director of clinical operations at Emergency Medicine Physicians and is an executive editor at Emergency Physicians Monthly.

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