Insurance Status, Not Race, Is a Determinant of Outcomes from Vehicular Injury

Abstract

Hypothesizing that outcomes from specific injury mechanisms should not vary by race or socioeconomic status, we analyzed the relationship of race and ethnicity to fatality in motor vehicle crash victims treated during 2008 and 2009. Logistic regression analysis of pooled administrative data assessed the contribution of patient demographics and injury severity to outcome, defined as mortality during acute hospitalization. Demographic factors included age, sex, race, ethnicity, and insurance. Severe injury was defined using ICD-9 Injury Severity Score (survival probability) p < 0.85, presence of up to 3 comorbidities, and/or diagnosis of spinal cord injury and/or traumatic brain injury. Mortality was stratified by survival time after trauma center arrival to death within 24 hours or thereafter. Factors contributing to outcomes were tested using chi square analysis of the calculated model estimate. For 8,758 motor vehicle crash victims treated in state-designated trauma centers, age, sex, injury severity, and 2 or more comorbidities consistently predicted survival. Neither race nor ethnicity was associated with increased mortality risk. Being uninsured was related to death within 24 hours (p < 0.001). The majority of the uninsured who died within 24 hours had an ICD-9 Injury Severity Score p ≤ 0.5. Mortality risk after 24 hours was driven by traumatic brain injury and comorbidities. The results of this study indicated that higher immediate mortality of the uninsured is a behavioral and socioeconomic rather than physiologic marker. This higher mortality is driven by increased injury severity that increases cost of care in uninsured survivors. This disparity suggests that risk-taking behavior, especially relating to safety practices and licensing regulations, is an important etiologic factor. Improved outcomes require better public education and enforcement in conjunction with improvements in processes of care.