The surprising finding suggests that patients with insurance are less likely to receive high-quality care than those without insurance, the Stanford University School of Medicine researchers said.
The study authors analyzed more than 4,500 critically injured patients seen at 636 hospital emergency departments across the United States in 2009. They found that insured patients taken to non-trauma hospitals were 13 percent to 15 percent less likely to be transferred to trauma centers than uninsured patients.
"Insured patients may, ironically, get worse outcomes because they are taken care of at a center where there's a lower volume of resources for critically injured patients," study author Dr. M. Kit Delgado, a former Stanford emergency medicine instructor, said in a university news release.
"We hypothesize that non-trauma center hospitals are more likely to want to admit insured patients presumably because they can get reimbursed for their services," said Delgado, who is now an emergency care research scholar at the University of Pennsylvania.
The study was published online Feb. 19 in the journal JAMA Surgery.
In the United States, shootings and traffic collisions are the most common causes of death among people younger than 44. Previous research has shown that severely injured patients are 25 percent less likely to die if treated at a top-ranked trauma center than at a non-trauma center.
"Finding disparities in quality of trauma care based on insurance is very disturbing," study senior author Dr. Nancy Wang, an associate professor of emergency medicine at Stanford, said in the news release.
"It is important for researchers to identify and call attention to these disparities in access to care and outcomes so that all people can receive the appropriate, high-quality care, regardless of their insurance status," she added.
The American College of Emergency Physicians offers injury prevention tips.