Health Policy Journal Club, Health Policy, Administration & Operations, Social EM

Health Policy Journal Club: Final Destination

ESI Level Often Leads to Under- and Over-Triage

More than 70 percent of emergency departments across the United States utilize the Emergency Severity Index (ESI) system— a 5-tier category combining vital signs with a subjective need assessment — to triage patients by perceived acuity. Both over- and under-triage are linked to worsened patient outcomes and misappropriation of hospital resources.

Given the severity of ED crowding, a precise triage process is necessary for prompt identification of individuals at risk of decompensation and to distinguish those who may be safely discharged with minimal resource investment. Prior studies have suggested the inaccuracy of the ESI system, though a standardized methodology to characterize patient mistriage is lacking. The study authors developed an algorithm combining the number of resources utilized with the presence of any 4-tiered "critical" interventions (medication or procedure) to characterize objective definitions of over- and under-triage.

The algorithm was applied to a 5-year retrospective cohort of all adult patients across 21 community EDs in the Kaiser Permanente Health System. Calculated rates of mis-triage were analyzed against patient and visit characteristics to assess for trends. In more than 3 million encounters, the authors determined 3.3% to have been under- and 28.9% to have been over-triaged, respectively. Of those, 32.8% of all under-triaged and 24.3% of all over-triaged encounters were determined to be "meaningful" based upon predetermined criteria. Recent ICU admission and insulin or sulfonylurea use significantly increased the risk of under-triage — the latter due to the frequent need for dextrose administration. Black and Hispanic patients were also at significant risk for mis-triage in both directions. Importantly, the sensitivity of ESI to identify critically ill patients (ie, appropriate ESI I or II) was just 65.9%.

Accurate patient triage is a vital component of efficient patient throughput and optimal ED function. Effective triage methodology is especially important given our current rates of ED crowding, attributable to a national boarding crisis and rising patient volumes and acuity. ESI is an inherently subjective measure, and this subjectivity is a likely contributor to significant rates of mis-triage— especially for Black and Hispanic patients.

While the study does not outline an alternative triage method, it does suggest objective measures that may improve the accuracy of the triage process, such as recent admissions or certain medications, and provides the tools necessary for health systems to assess their own triage accuracy. Given ESI largely determines a patient's disposition within the ED, physicians must be aware of the inaccuracy of this widely used system and its poor sensitivity in identifying critically ill patients. Patients assigned to low acuity areas may well harbor dangerous pathology, and physicians must not let ESI sway their clinical judgment or risk falling prey to the triage cueing bias.

Sac SR, Warton EM, Mark DG, et al. Evaluation of the Emergency Severity Index in US Emergency Departments for the Rate of Mistriage. JAMA Netw Open. 2023;6(3):e233404.

Background: Accurate emergency department (ED) triage is essential to prioritize the most critically ill patients and distribute resources appropriately. The most used triage system in the U.S. is the Emergency Severity Index (ESI).

Objectives: To derive and validate an algorithm to assess the rate of mistriage and to identify characteristics associated with mistriage.

Design, setting, and participants: This retrospective cohort study created operational definitions for each ESI level that use ED visit electronic health record data to classify encounters as undertriaged, overtriaged, or correctly triaged. These definitions were applied to a retrospective cohort to assess variation in triage accuracy by facility and patient characteristics in 21 EDs within the Kaiser Permanente Northern California (KPNC) health care system. All ED encounters by patients 18 years and older between Jan. 1, 2016, and Dec. 31, 2020, were assessed for eligibility. Encounters with missing ESI or incomplete ED time variables and patients who left against medical advice or without being seen were excluded. Data were analyzed between Jan. 1, 2021, and Nov. 30, 2022.

Exposures: Assigned ESI level

Main outcomes and measures: Rate of under-triage and over-triage by assigned ESI level based on a mistriage algorithm and patient and visit characteristics associated with under-triage and over-triage

Results: A total of 5,315,176 ED encounters were included. The mean (SD) patient age was 52 (21) years; 44.3% of patients were men and 55.7% were women. In terms of race and ethnicity, 11.1% of participants were Asian, 15.1% were Black, 21.4% were Hispanic, 44.0% were non-Hispanic White, and 8.5% were of other (includes American Indian or Alaska Native, Native Hawaiian or other Pacific Islander, and multiple races or ethnicities), unknown, or missing race or ethnicity. Mistriage occurred in 1,713,260 encounters (32.2%), of which 176,131 (3.3%) were under-triaged and 1,537,129 (28.9%) were over-triaged. The sensitivity of ESI to identify a patient with high-acuity illness (correctly assigning ESI I or II among patients who had a life-stabilizing intervention) was 65.9%. In adjusted analyses, Black patients had a 4.6% (95% CI, 4.3%-4.9%) greater relative risk of over-triage and an 18.5% (95% CI, 16.9%-20.0%) greater relative risk of under-triage compared with White patients, while Black male patients had a 9.9% (95% CI, 9.8%-10.0%) greater relative risk of over-triage and a 41.0% (95% CI, 40.0%-41.9%) greater relative risk of under-triage compared with White female patients. High relative risk of under-triage was found among patients taking high-risk medications (30.3% [95% CI, 28.3%-32.4%]) and those with a greater comorbidity burden (22.4% [95% CI, 20.1%-24.4%]) and recent intensive care unit utilization (36.7% [95% CI, 30.5%-41.4%]).

Conclusions and relevance: In this retrospective cohort study of more than 5 million ED encounters, mistriage with ESI was common. Quality improvement should focus on limiting critical undertriage, optimizing resource allocation by patient need, and promoting equity.

EMRA + PolicyRx Health Policy Journal Club: A collaboration between Policy Prescriptions and EMRA

As emergency physicians, we care for all members of society, and as such have a unique vantage point on the state of health care. What we find frustrating in our EDs - such as inadequate social services, the dearth of primary care physicians, and the lack of mental health services - are universal problems. As EM residents and fellows,  we learn the management of myocardial infarctions and traumas, and how to intubate, but we are not taught how health policy affects all aspects of our experience in the ED. Furthermore, given our unique position in the health care system, we have an incredible opportunity to advocate for our patients, for society, and for physicians. Yet, with so many competing interests vying for our conference education time, advocacy is often not included in the curricula. This is the gap this initiative aims to fill.  Each month, you will see a review of a new health policy article and how it is applicable to emergency physicians.  

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