Over the last 50 years, emergency departments (EDs) have become the hub of acute care, with relentless increases in patient volumes and unprecedented access to high level diagnostic technology and hospital resources, with the majority of patient visits paid by public funds. EDs have evolved in a relatively short time to become the de facto site for acute, unscheduled care. The development of data sources and record-keeping has struggled to keep pace, with a resulting gap in the ability of policymakers and payors to structure surveillance methods, measure quality, and determine fiscal effectiveness.

There are two sources of national data on ED visits. The Nationwide Emergency Department Sample (NEDS), performed by the Agency for Healthcare Research and Quality (AHRQ), is a portion of the Healthcare Cost and Utilization Project (HCUP). NEDS data is available from 2006 through 2020. The 2020 NEDS database year includes discharge data for ED visits from 995 hospitals located in 40 states and the District of Columbia, approximating a 20-percent stratified sample of U.S. hospital-owned EDs.

The other source is the Center for Disease Control and Prevention’s (CDC’s) National Center for Health Statistics (NCHS), which has conducted and released data from the National Hospital Ambulatory Medical Care Survey (NHAMCS) since 1992. The ED component of the National Ambulatory Medical Care Survey (NHAMCS) has been a nationally representative survey of nonfederal, general, and short-stay hospitals that is conducted annually. NHAMCS uses a multistage probability design with samples of geographic primary sampling units (PSUs), hospitals within PSUs, and patient visits within EDs. The latest NHAMCS ED survey report is from 2020 and consists of 26 data tables that were constructed from NAHMCS data. The survey is based on a sampling of 14,860 ED patient case reports from 294 emergency departments.

Major Changes to Come: ACEP Working for You

The CDC’s NCHS announced plans to update their ED data collection in coming years with the expansion of its NHCS, which collects ED data from a national sample of hospitals through the submission of UB-04 claims and EHR encounters for the entire calendar year. This is a change which reflects the importance of ED data. It has become even more important in following pandemic effects on ED visits, and creating dashboards that continue to track troubling impacts of infectious diseases, mental health care gaps, and increasing health care implications of substance use.

ACEP has been a driver of this change. ACEP has strongly supported the efforts of the CDC for the timely collection, analysis, and reporting of NHAMCS data, which supports emergency physicians and the changing practice of emergency medicine. The ACEP Qualified Clinical Data Registry—Clinical Emergency Data Registry (CEDR)—was launched in 2015 and has built secure data pipelines to a large nationwide network of EDs. The network has compiled structured and blinded data on more than 100 million ED visits and has become the primary submission source of standardized ED patient care data to the NCHS. The CDC has realized the efficiency and quality of this data source, and has begun to use this as a supplemental data source for their NHCS.