Older patients have increased risk of poor outcomes after low-velocity pedestrian–motor vehicle collisions

Abstract

BACKGROUND Motor vehicle collisions (MVCs) are a leading cause of injury in the US. While the probability of collision with a pedestrian (PMVC) has declined in recent years, the probability of a pedestrian fatality has risen. Our objective was to determine whether older age impacts potential outcomes in patients involved in low-velocity PMVCs. MATERIALS AND METHODS We performed a retrospective-cohort study of adult patients aged >14 years involved in low-velocity pedestrian-MVCs (<15 miles per hour [24.14 km/h]), presenting to an urban level I trauma center from January to November 2013. Subjects were identified via trauma registry and stratified: ages 15-49 years and ≥50 years. Electronic medical records were reviewed for demographics, vital signs, and laboratory results on initial presentation, presence or absence of systemic inflammatory response syndrome (SIRS), shock index (SI), injury-severity score (ISS), length of stay (LOS), and survival to discharge. For statistical analysis, χ(2) or Student's t-tests were utilized. RESULTS Our study included 145 patients (77 female) with a mean age of 41.9±3 years; 95 patients were aged 15-49 years (mean 31.9±2.2 years), and 50 patients were aged ≥50 years or older (mean 62.44±2.9 years). Mean ISS was 10.05±1.95, mean SI was 0.68±0.03, and mean LOS was 3.67±0.57 days. A total of 41 patients met SIRS criteria on arrival, and nine patients expired (6.2%). Mean ISS (15.64±4.42 vs 7.1±1.64, P<0.001) and mean SI (0.75±0.07 vs 0.65±0.03, P=0.002) were higher in patients aged ≥50 years. Mean LOS was longer in older patients (5.22±1.14 vs 2.85±0.58 days, P<0.001). Older age was associated with SIRS on arrival (P=0.023) and associated with mortality (P=0.004). CONCLUSION Age ≥50 years is associated with greater severity of injury and poor outcomes for patients involved in low-velocity PMVCs. Increased clinical attention and resource allocation should be directed toward older patients after low-velocity PMVCs.