(Reuters Health) - Care at freestanding emergency departments may cost about 10 times more than similar treatment at urgent care centers, according to a Texas study that highlights the potential for patients to be surprised by their bills.

The average cost of care at a freestanding emergency room in Texas was $2,199 in 2015, compared with $168 at urgent care, the study found. Either way, patients had to pay roughly one third of the tab out-of-pocket.

“We think patients may confuse freestanding emergency rooms with urgent care,” said lead study author Vivian Ho of Rice University in Houston.

“In Texas, they are both commonly found in suburban strip malls,” Ho said by email. “When people see a health care facility in that setting, they assume it won’t be as expensive as going to the hospital.”

For the study, Ho and colleagues analyzed insurance claims processed by Blue Cross and Blue Shield of Texas from 2012 to 2015.

While hospital emergency rooms and urgent care clinics accounted for the bulk of these claims, freestanding emergency departments experienced much more growth in use during the study period, researchers report in the Annals of Emergency Medicine.

In 2015, there were 1,046,545 visits to hospital emergency rooms and 926,933 to urgent care clinics, compared with just 183,971 visits to freestanding emergency departments.

During the study period, the number of freestanding emergency departments visited by patients in the database surged from 52 to 207 and the total number of visits jumped by 236 percent, from 54,696.

Prices at urgent care centers only rose 2 percent over the study period, while prices at hospital-based emergency rooms climbed 23 percent and prices at freestanding emergency departments soared 54 percent.

By the end of the study, average prices at hospital emergency rooms were $2,259, or about $60 more than at freestanding emergency departments.

When researchers looked at prices in different settings for the most common conditions treated, they found average prices were much higher at freestanding emergency departments than at urgent care.

For example, treatment for upper respiratory infections cost $1,351 at freestanding emergency rooms and $165 at urgent care clinics. At hospital-based emergency rooms, the price was $1,074.

One limitation of the study is that the severity of diseases or injuries might have varied at the different facilities, the authors note. They also lacked data on the total amount of money patients ultimately paid out-of-pocket for their care.

Another shortcoming is that the study didn’t include patients with other types of insurance including government programs like Medicare, Medicaid and Tricare.

Treating patients with these other types of insurance might bring down the average amounts paid out to hospital emergency rooms because those programs typically reimburse at a lower rate than private insurance, said Dr. Erin Simon, a researcher at Cleveland Clinic Akron General in Ohio who wasn’t involved in the study.

“Independent freestanding emergency departments are not able to bill those patients and must absorb those costs, and neither of those factors are addressed in this study,” Simon said by email.

Freestanding emergency departments may offer better access to care because they’re often located closer to where patients live and can cut travel time in emergencies, noted Dr. Nitish Patidar, a researcher at Quinnipiac University in Hamden, Connecticut who wasn’t involved in the study.

In some emergencies, patients might need to be transferred to a hospital, but the quality of care should generally be similar between freestanding emergency departments and hospital-based emergency rooms, Patidar said.

Patients do need to know when to try urgent care and when to visit emergency rooms, said Dr. Benjamin Lawner, medical director of prehospital care services for LifeFlight and EMS at Allegheny General Hospital in Pittsburgh, Pennsylvania.

“Urgent care centers are most suitable for convenience type of care,” Lawner said by email. “If a patient has a sore throat, cough, cold, or laceration, the urgent care center represents an accessible and efficient means of care,” he said.

“For possible life threatening situations such as chest pain, trouble breathing, weakness or significant injury, I’d recommend a freestanding emergency department or hospital emergency department,” Lawner added.

SOURCE: bit.ly/2oHDOvg Annals of Emergency Medicine, online February 15, 2017.