Pooled Analysis of Trauma Centers Better Predicts Risk Factors for Firearm Violence Reinjury.

Introduction: Many trauma centers use the first firearm injury admission as a reachable moment to mitigate reinjury. Understanding repeat firearm violence can be difficult in metropolitan areas with multiple trauma centers and laws that prohibit sharing private health information across health systems. We hypothesized that risk factors for repeat firearm violence could be better understood using pooled data from two major metropolitan trauma centers.

Methods: Two level I trauma center registries were queried (2007-2017) for firearm injury admissions using International Classification of Diseases, Ninth and Tenth Revision (ICD9/10) Ecodes. A pseudo encryption tool allowed sharing of deidentified firearm injury and repeat firearm injury data without disclosing private health information. Factors associated with firearm reinjury admissions including, age, sex, race, payor, injury severity, intent, and discharge, were assessed by multivariable logistic regression.

Results: We identified 2145 patients with firearm injury admissions, 89 of whom had a subsequent repeat firearm injury admission. Majority of repeat firearm admissions were assaulted (91%), male (97.8%), and non-Hispanic Black (86.5%). 31.5% of repeat firearm injury admissions were admitted to a different trauma center from their initial admission. Independent predictors of repeat firearm injuries were age (adjusted odds ratio [aOR] 0.94, P < 0.001), male sex (aOR 6.18, P = 0.013), non-Hispanic Black race (aOR 5.14, P = 0.007), or discharge against medical advice (aOR 6.64, P=<0.001).

Conclusions: Nearly a third of repeat firearm injury admissions would have been missed in the current study without pooled metropolitan trauma center data. The incidence of repeat firearm violence is increasing and those at the highest risk for reinjury need to be targeted for mitigating interventions.