The Severity of Disparity: Increasing ISS Accentuates Disparate Outcomes Following Injury

Abstract

Introduction: Multiple studies have demonstrated disparities in trauma mortality based on race and health insurance status. the underlying causes of these disparities are still largely unknown. Elucidating what groups are most at riskmay help in understanding these mechanisms. Given the predictable effect injury severity has on mortality, we sought to determine if injury severity modifies previously reported race and insurance status based disparities in survival after blunt traumatic injury. Methods: Adults (ages 18-64) in the 2003-2008 National Trauma Data Bank were stratified into six groups based on race and insurance status. Patients with Injury Severity Score (ISS) >=9 were included. Multivariable logistic regression compared the odds of death between the six race/insurance groups within different injury severity levels (ISS 9-15; ISS>15 & Systolic Blood Pressure (SBP)>90; ISS>15 & SBP<90). Age, gender, ISS, Glasgow Coma Scale (GCS) motor, presence of hypotension (SBP<90), admission year, and mechanism of injury were controlled for. Clustering was used to control for potential inter facility survival outcomes differences. Results: 760,598 patients met inclusion criteria. Crude mortality for moderately injured white insured patients was 0.75% and 1.52% (p<0.01) for uninsured blacks. for the hypotensive severely injured group, the difference in mortality increased to 34.5% for insured whites compared to 58.9% for uninsured black patients (p<0.01). (Figure) Adjusted analysis revealed an increase in disparities between race/insurance groups as the degree of injury worsened. (Table) Conclusions: Disparities in trauma mortality effecting minority and uninsured patients appear to worsen with increasing injury intensity. Understanding why the most severely injured suffer from even greater disparities may help us develop effective solutions to mitigate these inequities. TableAdjusted Odds Death for 6 Race/Insurance Groups by Injury White Black Hispanic White Black Hispanic Insured Insured Insured Uninsured Uninsured Uninsured Moderately Injured (ISS=9-15) 1(ref) 1.38 ∗ p<0.05 ,Adjusted for age, Gender, GCS motor score, ISS, mechanism of injury, year of admission, and inter-facility differences. (1.21,1.69) 1.39 (0.74,2.56) 1.11 (0.93,1.32) 1.73 ∗ p<0.05 ,Adjusted for age, Gender, GCS motor score, ISS, mechanism of injury, year of admission, and inter-facility differences. (1.34, 2.24) 1.02 (.75,1.37) Normotensive Severely Injured (ISS>=16 & SBP>90) 1 (ref) 1.33 ∗ p<0.05 ,Adjusted for age, Gender, GCS motor score, ISS, mechanism of injury, year of admission, and inter-facility differences. (1.18,1.49) 1.53 ∗ p<0.05 ,Adjusted for age, Gender, GCS motor score, ISS, mechanism of injury, year of admission, and inter-facility differences. (1.22,1.91) 1.59 ∗ p<0.05 ,Adjusted for age, Gender, GCS motor score, ISS, mechanism of injury, year of admission, and inter-facility differences. (1.44,1.75) 2.11 ∗ p<0.05 ,Adjusted for age, Gender, GCS motor score, ISS, mechanism of injury, year of admission, and inter-facility differences. (1.84,2.43) 1.81 ∗ p<0.05 ,Adjusted for age, Gender, GCS motor score, ISS, mechanism of injury, year of admission, and inter-facility differences. (1.50,2.18) Hypotensive Severely Injured (ISS>=16 & SBP<90) 1 (ref) 1.53 ∗ p<0.05 ,Adjusted for age, Gender, GCS motor score, ISS, mechanism of injury, year of admission, and inter-facility differences. (1.29,1.83) 1.60 ∗ p<0.05 ,Adjusted for age, Gender, GCS motor score, ISS, mechanism of injury, year of admission, and inter-facility differences. (1.31,1.94) 2.15 ∗ p<0.05 ,Adjusted for age, Gender, GCS motor score, ISS, mechanism of injury, year of admission, and inter-facility differences. (1.84,2.51) 3.17 ∗ p<0.05 ,Adjusted for age, Gender, GCS motor score, ISS, mechanism of injury, year of admission, and inter-facility differences. (2.25,4.46) 2.76 ∗ p<0.05 ,Adjusted for age, Gender, GCS motor score, ISS, mechanism of injury, year of admission, and inter-facility differences. (2.15,3.55) ∗ p<0.05 ,Adjusted for age, Gender, GCS motor score, ISS, mechanism of injury, year of admission, and inter-facility differences. Open table in a new tab