Secondary overtriage: impact of trauma center designation and trauma system integration

Background: Secondary overtriage in trauma refers to the interfacility transfer of minimally and moderately injured patients who do not require major interventions, resulting in short stays at tertiary receiving facilities. Secondary overtriage rates are commonly used as a measure of trauma system efficiency, focused on the optimal allocation and use of healthcare resources. However, limited data exist examining the impact of Level III trauma centers (L3TC) on secondary overtriage rates. Therefore, this study aimed to determine whether transfer from L3TCs, compared with non-trauma facilities, was associated with a lower rate of secondary overtriage among patients subsequently admitted to a Level I trauma center. Methods: This was a single-center, retrospective cohort study of trauma patients transferred to a tertiary trauma center between 1 August 2021 and 31 July 2023. The primary exposure was the American College of Surgeons-verified or state-designated trauma center level of the referring facilities. Multiple variable regression analysis was applied to three models: (1) unadjusted, (2) adjusted for patient characteristics and (3) adjusted for patient and hospital characteristics. Results: A total of 2309 patients were transferred to our tertiary trauma center from 20 referring facilities, including 15 non-L3TCs and 5 L3TCs. Secondary overtriage rates were significantly lower at L3TCs (23.5% vs 28.4%, p=0.009). On multivariable regression analysis, even after adjusting for patient and hospital characteristics, the odds of secondary overtriage from non-L3TCs remained 31% higher compared with L3TCs (OR: 1.31 (1.02, 1.67)). Non-L3TC transfer patients had a 12% shorter average hospital length of stay (LOS), a 21% shorter average intensive care unit LOS, and a 39% shorter average ventilator LOS (all p