Factors influencing secondary overtriage in trauma patients undergoing interhospital transfer: A 10-year multi-center study in Hong Kong.

Background: With the development of regionalised trauma networks, interhospital transfer of trauma patients is an inevitable component of the trauma system. However, unnecessary transfer is a common phenomenon, and it is not without risk and cost. A better understanding of secondary overtriage would enable emergency physicians to make better decisions about trauma transfers and allow guidelines to be developed to support this decision making. This study aimed to describe the pattern of secondary overtriage in Hong Kong and identify its associated factors.

Methods: This was a retrospective review of 10-years of prospectively collected multi-center data from two trauma registries in the New Territories of Hong Kong (2013-2022). The primary outcome is secondary overtriage, which was defined as early discharge alive within 48 h, Injury Severity Score (ISS) <15, and no surgical operation done. Patient characteristics, physiology, anatomy and investigation variables were compared against secondary overtriage using univariate and multivariable analyses.

Results: During the study period, 3852 patients underwent interhospital transfer from a non-trauma center to a trauma center, and 809 (21 %) of the transfers were considered secondary overtriage. The secondary overtriage rate was higher in pediatric age groups at 34.8 % (97/279). Logistic regression analysis showed secondary overtriage to be associated with blunt trauma and an Abbreviated Injury Scale (AIS) score of <3 for head or neck, thorax, abdomen and extremities.

Conclusion: Interhospital transfer is an essential component of the trauma system. However, over one-fifth of the transfers were considered unnecessary in Hong Kong, and this could be considered to be an inefficient use of resources as well as cause inconvenience to patients and their families. We have identified related factors including blunt trauma, AIS <3 scores for head or neck, thorax, abdomen and extremities, and opportunities to establish and improve on transfer protocols. Further research should be aimed to safely reduce interhospital transfers in the future to improve the efficiency of the Hong Kong trauma system.