Black patients are less likely than whites to be hospitalized at private academic medical centers in New York City, a new study has found. Those findings resurrect the hot-button belief that some private hospitals with deep pockets leave care for the sickest and poorest patients to a struggling public hospital system. Some hospitals already have pushed back against the study’s findings and its implications that New York City’s hospital system is a highly segregated one.

The study, published Thursday in the International Journal of Health Services, concluded that in New York City, black patients were two to three times less likely than whites to be discharged from these private academic medical centers, which are often perceived as providing superior medical care. It also found that uninsured patients were five times less likely than privately insured patients to be discharged from these hospitals.

“In a lot of U.S. cities, academic medical centers do function as safety net hospitals,” said Roosa Tikkanen, the lead author of the study, who was a research assistant at City University New York Hunter College at the time of the study and is now a policy analyst at the University of Massachusetts Medical School. “But in New York City, the system is different because there is this public hospital system,” she added.

Tikkanen was referring to New York City Health + Hospitals Corporation, the largest public hospital system in the U.S., with 11 acute-care hospitals across the city’s five boroughs serving more than one million patients every year.

Patients who are on Medicaid or have no insurance at all represent nearly 70% of New York City Health + Hospital Corporation’s hospital stays, and the system faces a budget gap of $1.8 deficit in 2020. NYC H+H was unable to provide a comment for this story by deadline.

But as not-for-profit hospitals, the city’s academic medical centers are also required by state law to provide community benefits, such as charity care, Tikkanen pointed out. Their not-for-profit status grants them subsidies in the form of certain tax exemptions, yet the state does not specify a minimum level of community benefits they must provide.

“What we are trying to raise is that perhaps there should be a shared responsibility in New York City,” Tikkanen said. “If we do require them to operate as charities, we should perhaps be setting some minimum requirements for how much charity care they do provide.”

One reason academic medical centers might see fewer minority and uninsured patients is become some of them lack publicly available emergency rooms, which is often the entry point to hospitals for uninsured patients. For a variety of reasons, minorities are more likely to lack health insurance than whites.

The inspiration for the study stemmed in part from the desire to see whether the findings of a 2006 study still held true, Tikkanen said. That report, by the Bronx Health REACH coalition, showed in part that private hospitals in New York City saw fewer minority or poor patients than their public counterparts, even in the same geographic areas, still held true, especially after the enactment of the Affordable Care Act in 2010.

In general, researchers found, patients at New York academic medical centers were older and more likely to be white and commercially insured, compared to patients at non-academic medical centers. They compared those statistics to academic medical centers in Boston, where minorities were overrepresented and patients were younger, more likely to be privately insured, and less likely to be white.

In both cities, a patient who was uninsured or who had Medicaid was less likely to end up at an academic medical center than a privately insured patient, the study found.

For their study, the researchers, who also came from Boston Medical Center and Harvard Medical School, analyzed the race/ethnicity and insurance coverage of adults discharged from hospitals in New York City in 2009 and 2014 and in Boston in 2009. They used data from New York City’s Statewide Planning and Research Cooperative System database and from the Massachusetts Center for Health Information and Analytics.

Tikkanen acknowledged that the study had certain limitations. The researchers used data from 2009 to compare the cities because that was the only year for which data for Boston were available, she said. And the 2014 data for New York City were the most recent available at the time the study began.

Another significant limitation of the study was that if it excluded the Boston Medical Center as an academic medical study, black patients in Boston became 40% less likely than whites to be discharged from an academic medical center.

Although Boston Medical Center is a private academic medical center, it behaves like a public hospital, Tikkanen said, because it was born of a merger between a public hospital and a university medical center. “The results were not so encouraging for Boston either, if we discount Boston Medical Center,” she said. However, the researchers also applied a system-wide index of segregation, which suggested that New York City hospitals still had higher levels of overall segregation between public and private hospitals.

The Greater New York Hospital Association called the study “significantly flawed” and an “apples to beans” comparison whose conclusions were incorrect.

“Academic medical centers in every city have a lower proportion of disadvantaged patients than the community hospitals in their cities because AMCs serve large geographic areas encompassing the cities they’re located in as well as the cities’ suburbs,” Kenneth Raske, the association’s president, said in a statement. “Community hospitals tend to serve city residents only,” he added.

Raske further disputed the study’s findings by adding that the use of 2014 data did not fully capture mergers among New York City hospitals since then, such as Mount Sinai Medical Center’s taking over St. Luke’s-Roosevelt Medical Center and Beth Israel Medical Center, two institutions that serve high proportions of Medicaid patients.

Dr. Andrew Racine, the senior vice president and chief medical officer of Montefiore Health System, of which two hospitals were included in the study, said the basis of the findings were “not untrue, in the sense that I do think that the distribution of patients in New York City with respect to who’s going to academic medical centers for treatment probably is different from Boston.”

“The question is, what does that mean?” he asked. There was probably greater variation in patient mixes among hospitals within New York City than between New York and Boston, he said. He cautioned against jumping to the conclusion that hospitals were discriminating against or refusing to provide care to poor people and minorities, suggesting that geography — where the academic institutions were, compared to where patients lived — could play a role.

Still, the study is not the first to suggest that brand-name not-for-profit hospitals, including academic medical centers, are not providing their fair share of charity care.

In 2014, the New York Post reported that top nonprofit hospitals spent less than 2% of revenues on charity care, while compensating CEOs with millions of dollars. In 2012, it reported, New York Presbyterian took in $3.9 billion in revenue but spent $37.6 million on charity care. That year, it paid its executive vice chairman $5.5 million and its CEO $3.58 million.

The private academic medical centers in New York included in the study were Hospital for Special Surgery, Memorial Sloan-Kettering Hospital for Cancer, Montefiore Medical Center’s Jack D. Weiler Hospital and Henry and Lucy Moses Division, Mount Sinai Medical Center, New York University Hospital for Joint Diseases, NYU Langone Medical Center/Tisch Hospital, New York Presbyterian-Columbia University Medical Center, NYP Weill Cornell Medical Center and Long Island Jewish Medical Center.

In Boston, the study looked at Beth Israel Deaconess Medical Center, Boston Medical Center, Brigham and Women’s Hospital, Massachusetts General Hospital, Tufts Medical Center and Dana Farber Cancer Institute.