With nearly 150 million emergency department (ED) visits each year, of which over 20 million result in a hospital admission, emergency care plays a significant role in health care delivery and population health [1]. Disparities in emergency care by sex, race, and ethnicity are well documented [[2], [3], [4], [5]]. These disparities are likely due to a complex interplay of factors, including explicit and implicit biases, sociocultural differences, and systemic sexism and racism. With an increasingly diverse patient population, the ED is an ideal setting in which to understand, address, and achieve equity in health care.

In 2021, the American College of Emergency Physicians (ACEP) convened a multi-disciplinary work group on the development of quality measures to address disparities in ED care [6]. The workgroup suggested measurement of disparities should focus on the processes of care delivery. There is growing evidence that women and racial and ethnic minorities are undertriaged in the ED compared to male and White patients [[7], [8], [9], [10], [11]]. With some inherent subjectivity, the triage nurse's initial assessment and assignment of acuity level are prone to inequitable decisions [12]. Prior research has also identified significant sex-race interactions in ED triage although the results vary by ED setting and populations [11,13]. Further, inequities in triage could be exacerbated during suboptimal ED operating conditions (e.g., crowding) because cognitive stress can cause clinical decision makers to rely on personal biases [14]. Investigation of the factors that influence the ED triage disparities can inform the development of measures and interventions to monitor and promote equitable emergency care delivery [6].

There is limited research on the role of ED conditions and settings in sex, racial, and ethnic disparities in ED triage. Therefore, with retrospective data from three diverse EDs, we estimated sex, racial, and ethnic differences in the assignment of Emergency Severity Index (ESI) [15], adjusting for patient age, clinical factors, and ED operating conditions. Female and minority race and ethnicity patients were hypothesized to have lower acuity ESIs assigned compared to male and White counterparts. Further, we tested whether ED-wide wait times modified any observed differences in ESI assignment by patient sex, race, and ethnicity. Results were stratified and compared by ED site to describe how ED triage disparities vary across different health care setting.