Self-Pay Trauma Victims Have a Higher Mortality Rate than Patients with Different Payment Methods

INTRODUCTION

The purpose of this study was to determine the association between a trauma patient’s health insurance status and their outcomes. Access to care was measured by using a patient’s method of payment. Previous studies have been conducted on a national scale but few have used a state registry as their primary data source. The Arizona State Trauma Registry (ASTR) provides this opportunity. We hypothesize that trauma patients who self-pay will have a higher in-hospital mortality when compared to others.

METHODOLOGY

The data for this study were obtained from the ASTR for years 2008 to 2011. Data on all patients involved in traumatic injury were collected from 8 Level I trauma centers, 15 Level IV trauma centers and 4 non-designated hospitals. Data processing and statistical analyses were performed using the Statistical Analysis Software (SAS, SAS Institute, Carry, N.C.). We evaluated the association between survival and insurance status (private insurance, Medicare, Medicaid, and self-pay) by multiple logistic regression analyses after adjusting for ethnicity (White, Black/African American, Hispanic, and American Indian/Alaska Native), age, gender, injury severity score, injury type (penetrating or blunt) and mode of transportation (EMS-air, EMS-ground, private vehicle).

RESULTS

Of the 109,497 cases meeting inclusion criteria, 14,573 (13.3%) were excluded due to missing data on insurance status, ISS or race/ethnicity. Of the 94,924 cases analyzed, 38% were Medicaid, 35.4% were private insurance, 13.7% were self-pay, and 12.8% were Medicare. The Self-pay group (17.3%) and Medicaid group (15%) were more likely to suffer from penetrating trauma when compared to the privately insured group (5.7%) and Medicare group (4.3%), p<0.0001. Additionally, the Self-pay group (4.5%) and Medicare group (5.1%) had higher mortality than the private (1.8%) and Medicaid insurance group (2.1%), p<0.0001. There were more Hispanic self-pay patients (41.4%) compared to the private insurance group (21.8%), Medicaid (37.2%) and Medicare group (12.6%) p<0.0001.

A simple logistic regression revealed higher in-hospital mortality for self-pay patients as compared to Medicaid (crude odds ratio [OR] 2.2, 95% confidence interval [CI] 2.0–2.5) and private insurance (crude OR 2.5, 95% CI 2.2–2.8). After adjusting for age, gender, race/ethnicity, ISS, and trauma type, a multiple logistic regression revealed highest in-hospital mortality for self-pay patients as compared to Medicare (adjusted OR 2.0, 95% CI 1.6–2.4), Medicaid (adjusted OR 2.9, 95% CI 2.5–3.3), and private insurance (adjusted OR 3.1, 95% CI 2.6–3.5).

Insurance Group	Unadjusted OR and 95% CI	Adjusted OR and95% CI
Self-pay group vs. Private	2.5 (2.2–2.8)	3.1 (2.6–3.5)
Self-pay group vs. Medicaid	2.2 (2.0–2.5)	2.9 (2.5–3.3)
Self-pay group vs. Medicare	0.8 (0.7–0.9)	2.0 (1.6–2.4)

CONCLUSIONS

These results demonstrate that after controlling for age, ISS, gender, type of injury and race/ethnicity, self-pay group has a significantly higher risk of in-hospital mortality following a traumatic injury as compared to any other insurance type groups in the ASTR. Limitations of the study include a lack of other available measures of socio-economic status (SES) such as income, occupation status and education, which may act as potential confounders. This conclusion should be analyzed across different states with varying insurance rates to fully consider its implications. Further research is needed to determine potential explanations for the increased mortality in this population.