Does age matter? The relationship between age and mortality in penetrating trauma.

Purpose: Trauma is a significant cause of mortality among elderly patients, with blunt mechanisms accounting for the majority of deaths in this population. Penetrating trauma promises to evolve as an increasingly important aetiology of mortality in the elderly; particularly as the age composition of the overall population continues to shift. Unfortunately, very little data regarding outcomes following penetrating trauma in the elderly exists. The purpose of this study was to define the relationship between age and mortality following penetrating injuries and determine if differences between outcomes of elderly patients sustaining penetrating and blunt trauma exist.

Methods: After IRB approval, we conducted a retrospective trauma registry review at an urban Level 1 trauma centre between January 1, 1998 and December 31, 2005. Demographic, injury, and mortality data for all patients were recorded. The relationship between age and mortality for both blunt and penetrating injuries was examined by comparison of age-specific mortality and relative risk of mortality for both mechanisms at 10 year age intervals. Additionally, the relative risk and 95% confidence interval for mortality in each age group were compared.

Results: There were 26,333 blunt trauma admissions and 8843 penetrating trauma admissions during the 8-year study period. The mortality following both blunt and penetrating trauma remained stable until the age of 55 and increased steadily thereafter. When differences in mortality following blunt and penetrating mechanisms were examined, the overall mortality of penetrating trauma was found to be 2.63 times that of blunt (11.0% vs. 4.2%, RR 2.63; 95% CI: 2.42, 2.85, p<0.0001). After adjustment for age and other confounding factors, the relative risk of mortality due to penetrating mechanisms was 1.65 (95% CI: 0.88, 2.89, p=0.10) that of blunt mechanism counterparts. Although statistically higher in penetrating trauma, the relative risk of mortality between penetrating and blunt trauma decreased with increasing age.

Conclusion: The mortality rate with respect to penetrating trauma remains relatively constant until the age of 55, increasing thereafter. When compared to blunt trauma, the relationship between age and mortality in penetrating trauma is similar except that the relative mortality in penetrating trauma is significantly higher for each age group.