High mortality in elderly drivers is associated with distinct injury patterns:: Analysis of 187,869 injured drivers

Background: Higher mortality in elderly drivers involved in motor vehicle collisions (MVCs) is a major concern in an aging population. We examined a spectrum of age-related differences in injury severity, outcome, and patterns of injuries using our institution's trauma registry and the National Trauma Data Bank. Methods: Injury severity scores (ISSs) and measures of outcome were compared among five age groups (< 26, 26 - 39, 40 - 54, 55 - 69, 70+ years) using chi(2) tests and analysis of variance. International Classification of Diseases-9th Revision (ICD-9) codes were used to compute the frequency of specific injuries across groups. We used stratified analysis and multiple logistic regression to control for confounding. Results: After the age of 25, injury severity, mortality, and length of stay (LOS) all increased progressively with age, whereas likelihood of discharge home decreased for each group (p < 0.001). Restraint use increased with age. However, age-related adverse outcomes were significantly increased even after adjusting for restraint use (p < 0.0001). Unrestrained elderly drivers had the highest mortality and morbidity (p < 0.001), and were least likely to be discharged home (p < 0.001). Abbreviated Injury Scale scores and ICD-9 codes indicated that poor outcomes with older age were driven primarily by head and chest injuries, especially intracranial hemorrhage, rib fractures, pneumothorax, and injury to the heart and lungs. Conclusions: Elderly drivers involved in MVCs have disproportionately poor outcomes primarily because of a greater incidence of head and chest injuries. Seat belt and airbag use in elderly drivers significantly reduce this trend but do not eliminate it. These observations should help establish clinical guidelines for the evaluation of traumatized elderly drivers, develop specific education programs, and safer vehicle design.