Diagnostic error is thought to be common, costly, and associated with substantial patient harm in the United States (U.S.). A recent report by the Agency for Healthcare Research and Quality (AHRQ) highlighted the importance of addressing diagnostic error in emergency care and called for additional research examining contemporary diagnostic errors rates in U.S. emergency departments (EDs). ED visits are common, with 1 in 5 Americans visiting the ED, leading to over 130 million ED visits annually. Diagnostic accuracy for emergency conditions is essential for optimal patient outcomes. Yet, the very nature of the ED, including unpredictable patient volume, limited time and available information, as well as frequent interruptions, can make diagnostic accuracy in the ED challenging. While there has been substantial attention paid to the variation in the quality of emergency care, there has been relatively less research on diagnostic safety in the ED, as highlighted by the recent AHRQ report. This project will use representative national claims data to provide detailed evidence on the landscape of diagnostic error in U.S. EDs. We will quantify the rate of diagnostic error for high-risk emergency conditions as well as the common symptoms associated with these diseases. Additionally, we will examine the degree to which diagnostic error in emergency care is associated with patient harm. We will identify the patient, clinician, and hospital factors associated with greater risk of diagnostic error. Finally, we will examine if having an ambulatory follow-up visit after an ED diagnostic error can mitigate the harms associated with misdiagnosis. This national study will enable frontline clinicians and policymakers to understand the extent of diagnostic error in U.S. EDs and the factors that may be targeted for quality improvement efforts to address this important public health problem.

Emergency department (ED) visits are common, with 1 in 5 Americans visiting the ED each year. Diagnostic error is an important problem in healthcare, but there is little evidence from U.S. studies to indicate how often patients who visit the ED are misdiagnosed. This project will measure rates of misdiagnosis in emergency care and how misdiagnosis affects death rates and other patient harms. This project will also evaluate which patients, clinician and hospital factors affect misdiagnosis rates.