Should they stay or should they go? Who benefits from interfacility transfer to a higher-level trauma center following initial presentation at a lower-level trauma center Tessa Adzemovic, Thomas Murray, PhD, Peter Jenkins, MD, Julie Ottosen, MD, Uroghupatei Iyegha, MD, Krishnan Raghavendran, MD, Lena M. Napolitano, MD, Mark R. Hemmila, MD, Jonathan Gipson, MD, Pauline Park, MD, and Christopher J. Tignanelli, MD, Minneapolis, Minnesota BACKGROUND: Interfacility transfer of patients from Level III/IV to Level I/II (tertiary) trauma centers has been associated with improved out- comes. However, little data are available classifying the specific subsets of patients that derive maximal benefit from transfer to a tertiary trauma center. Drawbacks to transfer include increased secondary overtriage. Here, we ask which injury patterns are as- sociated with improved survival following interfacility transfer. METHODS: Data from the National Trauma Data Bank was utilized. Inclusion criteria were adults (≥16 years). Patients with Injury Severity Score of 10 or less or those who arrived with no signs of life were excluded. Patients were divided into two cohorts: those admitted to a Level III/IV trauma center versus those transferred into a tertiary trauma center. Multiple imputation was performed for miss- ing values, and propensity scores were generated based on demographics, injury patterns, and disease severity. Using propensity score–stratified Cox proportional hazards regression, the hazard ratio for time to death was estimated. RESULTS: Twelve thousand five hundred thirty-four (5.2%) were admitted to Level III/IV trauma centers, and 227,315 (94.8%) were trans- ferred to a tertiary trauma center. Patients transferred to a tertiary trauma center had reduced mortality (hazard ratio, 0.69; p < 0.001). We identified that patients with traumatic brain injury with Glasgow Coma Scale score less than 13, pelvic fracture, penetrating mechanism, solid organ injury, great vessel injury, respiratory distress, and tachycardia benefited from interfacility transfer to a tertiary trauma center. In this sample, 56.8% of the patients benefitted from transfer. Among those not transferred, 49.5% would have benefited from being transferred. CONCLUSION: Interfacility transfer is associated with a survival benefit for specific patients. These data support implementation of minimum evidence-based criteria for interfacility transfer. (J Trauma Acute Care Surg. 2019;86: 952–960. Copyright © 2019 American As- sociation for the Surgery of Trauma.) LEVEL OF EVIDENCE: Therapeutic/Care Management, Level IV. KEY WORDS: Interfacility transfer; triage; secondary overtriage; undertriage; trauma systems. T he goal of interfacility transfer of severely injured trauma patients is to ensure that patients are at the right place at the right time to receive safe, reliable, high-quality care. American College of Surgeons (ACS)-verified trauma centers voluntarily maintain four categories (I–IV) of readiness based on the quan- tity of human and material resources at the respective centers. 1 Level I and II centers are considered tertiary trauma centers and are expected to have similar clinical outcomes. 2 Current evidence suggests that interfacility transfer of some injured patients from Level III/IV trauma centers to Level I/II centers is associated with improved outcomes, including reduction in mortality. 3,4 Currently, it is agreed that the decision to transfer should be made based on the patient's clinical status and the facility's available resources. 1 The advantages are presumed to vary de- pending with the mechanism and severity of injury sustained by the patient; however, there are limited data regarding which specific patients actually derive a mortality benefit from interfacility transfer. 5 In addition, secondary overtriage—patient transfers from a nontertiary trauma center to a tertiary trauma center with a length of stay shorter than 48 hours and not requiring operative intervention—poses a burden to already saturated tertiary trauma centers and can potentially jeopardize the care of severely injured patients at these centers. Studies suggest secondary overtriage oc- curs in approximately 7% to 38% of tertiary trauma transfers, with the majority being patients with head and neck injuries. 6–8 The overall lack of benefit data renders clinical practice ambigu- ous, and it continues to vary from center to center. Submitted: September 7, 2018, Revised: December 19, 2018, Accepted: January 2, 2019, Published online: March 1, 2019. From the University of Michigan Medical School (T.A.), Ann Arbor, Michigan; Division of Biostatistics (T.M.), University of Minnesota, Minneapolis, Minnesota; Department of Surgery (P.J.), Indiana University, Indianapolis, Indiana; Department of Surgery (J.O., C.J.T.), University of Minnesota, Minneapolis, Minnesota; Department of Surgery (J.O., J.G.P., C.J.T.), North Memorial Health Hospital, Robbinsdale, Minnesota, Department of Surgery (U.I.), Regions Hospital, St. Paul, Minnesota; Department of Surgery (K.R., L.M.N., M.R.H., P.P.), University of Michigan, Ann Arbor, Michigan; and Institute for Health Informatics (C.J.T.), University of Minnesota, Minneapolis, Minnesota. This study was presented as a plenary presentation at the 77 th annual meeting of American Association for the Surgery of Trauma Meeting, September 26–29, 2018, in San Diego, California. Address for reprints: Christopher J. Tignanelli, MD, Department of Surgery, University of Minnesota, 420 Delaware St SE, MMC 195, Minneapolis, MN 55455; email: ctignane@umn.edu. DOI: 10.1097/TA.0000000000002248 AAST 2018 PODIUM P APER 952 J Trauma Acute Care Surg Volume 86, Number 6 Copyright © 2019 Wolters Kluwer Health, Inc. All rights reserved.