Emergency department care in the United States: a profile of national data sources.

STUDY OBJECTIVE: Emergency departments (EDs) are an integral part of the US health care system, and yet national data sources on the care received in the ED are poorly understood, thereby limiting their usefulness for analyses. We provide a comparison of data sources that can be used to examine utilization and quality of care in the ED nationally. DATA SOURCES AND COMPARISONS: This article compares 7 data sources available in 2005 for conducting analyses of ED encounters: the American Hospital Association Annual Survey Database(), Hospital Market Profiling Solution(c), National Emergency Department Inventory, Nationwide Emergency Department Sample, National Hospital Ambulatory Medical Care Survey, National Electronic Injury Surveillance System-All-Injury Program, and the National Health Interview Survey. In addition to describing the type and scope of data collection, available characteristics, and sponsor of the ED data sources, we compare (where possible) estimates of the total number of EDs, national and regional volume of ED visits, national and regional admission rates (percentage of ED visits resulting in hospital admission), patient characteristics, hospital characteristics, and reasons for visit generated by the various data sources.

MAJOR FINDINGS: The different data sources yielded estimates of the number of EDs that ranged from 4,609 to 4,884 and the number of ED encounters from more than 109 million to more than 116 million. Admission rates across data sources varied from 12.0% to 15.3%. Although comparisons of the 7 data sources were somewhat limited by differences in available information and operational definitions, variation in estimates of utilization and patterns of care existed by region, expected payer, and patient and hospital characteristics. The rankings and estimates of the top 5 first-listed conditions seen in the ED are relatively consistent between the 2 data sources with diagnoses, although the Nationwide Emergency Department Sample estimates 1.3 to 5.8 times more ED visits for each chronic and acute all-listed condition examined relative to the National Hospital Ambulatory Medical Care Survey.

CONCLUSION: Each of the data sources described in this article has unique advantages and disadvantages when used to examine patterns of ED care, making the different data sources appropriate for different applications. Analysts should select a data source according to its construction and should bear in mind its strengths and weaknesses in drawing conclusions based on the estimates it yields.