A new study from researchers at the University of Maryland School of Medicine has found that nearly half of all medical care in the United States happens in emergency rooms — and it may mean that vulnerable populations aren’t getting care that meets all their needs.

The study examined data between 1996 and 2010 and found that emergency rooms provided, on average, 47.7% of medical care in the U.S.

Among certain populations, those numbers were even higher. African-Americans, women, and Medicare and Medicaid recipients, for example, were more likely to get their medical care at emergency rooms.

In this photo taken, Nov. 30, 2010, nurses at University of Chicago Medical Center in Chicago work in the emergency room at the hospital. M. Spencer Green/AP

“I was stunned by the results,” Dr. David Marcozzi, an author of the study and an associate professor in the UMSOM Department of Emergency Medicine, said in a statement from the university. “This really helps us better understand health care in this country. This research underscores the fact that emergency departments are critical to our nation’s healthcare delivery system.”

According to Marcozzi, these findings mean that emergency rooms are providing vital care, especially for groups that face other barriers to accessing health care. “The data might suggest that emergency care provides the type of care that individuals actually want or need, 24 hours a day,” Marcozzi said.

In a phone call to Mic on Wednesday, Marcozzi explained that the reality of his research — that emergency care is filling vital health care needs — means that policy should adjust to reflect that reality.

“The emergency care system provides comprehensive care, anytime, day or night ... [emergency care] fills a very valuable need for the nation,” Marcozzi said, and policy changes to support emergency care in that function, and to better strengthen the connection between emergency care and outpatient primary care, are necessary.

According to Dr. Arefa Cassoobhoy, senior medical director at WebMD and senior medical correspondent at Medscape, the findings of this latest study also indicate that, while emergency rooms are providing necessary care, using them as a primary method of health care may mean that patients aren’t getting all their needs met — and that emergency rooms are becoming overcrowded.

“It’s not incredibly surprising reading this, but it is harsh looking at these numbers on paper,” Cassoobhoy said Tuesday.

The wait time at the Bayonne Medical Center’s emergency room is displayed on a billboard, April 12, 2011 in Jersey City, New Jersey. Julio Cortez/AP

Cassoobhoy said that it makes sense that so many people would turn to the emergency room for medical care. For people who face economic or language barriers that make it hard to access regular care, or for those with inadequate health insurance, “they can go there, and get their medical issues evaluated right there and then without having to go through the barriers of making an appointment.”

However getting care from an emergency room may mean that those patients are missing out on the kind of care that comes with seeing a primary care doctor. “The emergency room isn’t the place to meet that full spectrum of medical needs they may have … in terms of that long term relationship with a physician,” Cassoobhoy said.

It also means, she said, that an emergency room is “not working as efficiently as it could … because we’ve got so many people coming in for what isn’t an emergency.”

Cassoobhoy cautioned that the study only covered up to 2010, so its most recent data was from seven years ago, but the findings do indicate that more work needs to be done in addressing the needs of groups that are using the emergency room for their health care needs.

What needs to happen, Cassoobhoy said, is “really honing in on those populations and unpacking what the barriers are so we can address them systematically, that’s where we need to go.”

Speaking on Wednesday, Marcozzi acknowledged that there are systemic issues at play that lead to so many people relying on emergency care. “There’s absolutely an access problem with regard to our vulnerable populations ... and if we fixed that tomorrow, that would be wonderful,” Marcozzi said.

But that’s not the reality, Marcozzi said, and it’s crucial that policy reflect the importance of emergency care in the health care system.

“I’m all about trying to improve our system and improve access points,” he said. “But the data indicates that … this is a signifiant component of our health care system.”

Oct. 25, 2017, 11:35 a.m.: This story has been updated.

Correction: Nov. 21, 2017