Evaluation of the American Hospital Association Annual Survey for health services research in emergency medicine

OBJECTIVES: Emergency department (ED) data are often used to address questions about access to and quality of emergency care. Our objective was to compare one of the most commonly used data sources for national ED information, the American Hospital Association (AHA) Annual Survey, with a criterion database: the National Emergency Department Inventory (NEDI)–USA data set. METHODS: We compared the 2015 and 2016 AHA surveys to the following 3 criterion standards: (1) the 2015 and 2016 NEDI‐USA databases, which have information about all US EDs, including merged data from (2) Council of Teaching Hospitals (COTH) and (3) the Critical Access Hospital (CAH) program. We present descriptive results about the number of EDs in each data set; total and median visit volumes; locations in rural areas; and COTH, CAH, and freestanding ED (FSED) status. RESULTS: The AHA survey identified 3893 US EDs in 2015. These EDs had a total annual visit volume of 129,197,493 visits, with a median of 22,772 visits (interquartile range, 8311–47,938). Compared with the NEDI‐USA, the AHA included 1433 fewer EDs (−27%; 95% confidence interval [CI], −28% to −26%) and 23,615,163 (−15%) fewer visits. Specifically, AHA was missing 245 (−22%; 95% CI, −24% to −19%) of those located in rural areas, 268 (−20%; 95% CI, −22% to −18%) in a CAH, and 240 (−47%; 95% CI, −51% to −42%) FSEDs. We saw similar results using 2016 data. CONCLUSIONS: Although several aggregated results were similar between the compared data sources, the AHA data set excluded many US EDs, including many rural EDs and FSEDs. Consequently, the AHA underreported total ED visits by 15%. We encourage data users to be cautious when interpreting results from any 1 ED data source, including the AHA.