Factors Associated With Injury Severity in Oklahoma City Bombing Survivors

Background. Terrorist bombings are an increasing source of violent death and injury worldwide. Injuries in building bombings have been previously reported in descriptive studies, but no comparative analyses have quantitatively assessed factors influencing the severity of nonfatal bombing injuries. The objective of this study was to identify personal and environmental risk factors for injury severity in the Oklahoma City bombing, on April 19, 1995. Methods: We conducted a retrospective comparative analysis of 509 nonfatally injured occupants of four buildings surrounding the detonation site. The source of data was the 1995 Oklahoma City Bombing database, a registry of all injuries and fatalities related to the bombing. Multivariable logistic regression was used to assess two outcomes: (1) medically-attended injury among injured occupants; and (2) hospital admission among occupants with medically attended injuries. Results: Increased odds of sustaining medically attended injuries were associated with being struck by flying glass (adjusted odds ratio [AOR], 5.3; 95% confidence interval [CI], 1.9-14.8) and location above the first floor of buildings (OR, 4.0; 95% CI, 1.4-11.7) after adjustment for other factors. Adjusted odds of hospital admission were associated with location in the collapsed region (AOR, 43.4; 95% CI, 4.4-434.1), being blown by the blast wind (AOR, 5.3; 95% CI, 2.1-13.8), and being trapped (AOR, 3.1; 95% CI, 1.2-7.7). Conclusions. The severity of nonfatal injury in the Oklahoma bombing was primarily associated with structural and environmental factors. Improved architectural design may prevent many injuries in building bombings. These finding provide evidence for future injury prevention activities.