Your chances of surviving brain surgery might be affected by whether you have health insurance.

According to the findings of a new study by Johns Hopkins University researchers, uninsured patients died at a higher rate after receiving brain surgery to remove cancerous tumors than those with private insurance. Uninsured patients had a death rate of 2.6 percent, compared to 1.3 percent among the privately insured, a statistically significant difference.

“If you have some type of insurance, you’re going to do better,” said Dr. Alfredo Quiñones-Hinojosa, the study’s lead researcher, adding that survival rates for patients covered by Medicaid were slightly better than those for the uninsured, but the difference was not significant.

In the study, published this week in the Archives of Surgery, researchers reviewed the records of more than 28,000 patients and compared their in-hospital death rates based on insurance status. The study isn’t the first to link health insurance status to health outcomes. Previous research has documented the same pattern  among patients undergoing surgeries for other conditions, including cardiovascular disease.

But the factors causing uninsured patients to do worse aren’t entirely understood. “Whether we like it or not, this paper raises more questions than it answers,” Quiñones-Hinojosa said.

Researchers looked at several possibilities that could explain the study’s findings.

Previous research suggested that being uninsured may influence a patient’s overall health and ability to access care. The study was unable to address whether uninsured patients had undiagnosed medical conditions that might have contributed to their poorer outcomes, however.

Researchers also speculated that doctors may treat the uninsured differently. Quiñones-Hinojosa said he would like to conduct a future study that would follow surgical patients and analyze the care they receive. As for the higher death rates of Medicaid patients, Quiñones-Hinojosa suggested that one factor may be that doctors generally do not think highly of the federal-state program for the uninsured.

Quiñones-Hinojosa declined to offer an opinion about whether the expansion of coverage expected to take place in 2014 under the 2010 health care law, including an expansion of Medicaid, would improve health outcomes.

“This paper argues that patients with some sort of insurance don’t die as much [as those] without insurance,” he said. “One can logically ask … will having some sort of universal coverage lead to something in favor of patients not dying?”