Background

Recent attention has been paid to the role trauma centers play in responding to mass shootings. Although high-profile public events are the primary focus of media and policy makers, firearm-injured patients (FIPs) present in clusters to urban trauma centers every day. We examined the burden of FIP clusters from an urban trauma system perspective.

Study Design

In this descriptive epidemiologic study, we used data from the Philadelphia Police Department registry of shootings from 2005-2015. Variables included patient demographics, injury date and time, receiving hospital, and mortality. We defined clustered FIPs as those arriving within 15 minutes of another FIP. We used rolling temporal windows to calculate the number of FIP clusters for each hospital, assessed patient demographic characteristics and mortality, and used linear regression models to evaluate trends in FIP cluster rates.

Results

Of the 14,217 FIPs included, 22.1% were clustered. There were 54 events when ≥ 4 FIPs presented within 15 minutes and 92 events when ≥ 4 FIPs presented within 60 minutes. FIP clusters occurred most frequently during night shifts (19:00-7:00) (73.1%) at Level I trauma centers (93.6%), with geographic clustering demonstrated at the hospital level. Compared to the overall FIP population, clustered FIPs were more likely to be female (p=0.039), injured at night (p=0.031), but less likely to die (p=0.014). The rate of FIP clusters and mortality remained steady over the course of the study.

Conclusions

In the trauma system studied, FIP clusters are common and likely to occur at similar rates in other urban centers. Thus, the immediate burden on healthcare resources caused by multiple FIPs presenting within a short period of time is not limited to traditionally defined mass shootings.