The Impact of Area Deprivation Index, Geography, and Mechanism on Incidence of Ballistic Injury to the Upper Extremity.

INTRODUCTION This study investigates the intersection of ballistic injuries, geography, and Area Deprivation Index (ADI). We hypothesized that both ADI and geography are correlated with incidence of upper extremity ballistic injuries. Further, we characterize and compare 2 distinct upper extremity gunshot injury populations presenting to our institution: those sustaining violent ballistic injuries and those who suffer an accidental, self-inflicted injury. Our purpose is to evaluate the impact of geography and ADI on the pattern of upper extremity gunshot injuries in Illinois and Missouri. MATERIALS AND METHODS This was a retrospective review of adult patients sustaining ballistic injury to the upper extremity at a single urban level I trauma center over 10 years (n = 797). Seven hundred thirty patients had home addresses in Illinois or Missouri; these addresses were geocoded and included for analysis. Mechanism of injury was self-reported. ADI was measured from the 2019 Neighborhood Atlas, in which deprivation increases from 1 to 100. Comparisons between groups were conducted with unpaired t tests, Fisher exact test, or χ2 testing, where appropriate. RESULTS Addresses constituted 259 unique census tracts, and the average number of upper extremity gunshot wound incidents per tract was 3, with a maximum of 22; 15.4% of census block tracts made up almost half (48.4%) of the total ballistic injuries in the study period; 97.7% of violent injuries occurred in Urban areas, as compared with only 60% of accidental injuries (P < 0.05). ADI and incidence of upper extremity ballistic injury were positively correlated. ADI varied significantly between patients sustaining violent (median, 94; mean, 86.1) versus accidental self-inflicted (median, 79; mean, 70.9) injuries (P < 0.05). Fifty percent of violent injuries in our data set occurred in block groups from the 2 most deprived quintiles. CONCLUSIONS Upper extremity gunshot wounds in general are concentrated in census blocks with high ADI. Violent injuries in particular are more likely to occur in urban areas with high ADI, whereas patients with accidental, self-inflicted injuries are more geographically and socioeconomically diverse. These differing populations require unique approaches to reduce incidence and morbidity.