Even though the number of insured emergency room visits has stayed about the same in recent years, the cost to step inside the door has nearly doubled, according to new data released by a health care policy group.

In 2016, the average amount spent nationally by insurers and patients for emergency room visits was $247 per insured person. In 2009 it was $125, the Health Care Cost Institute research shows.

The reason for the spike appears to be a dramatic shift in how emergency visits are coded by facilities, with many more designated at the highest levels of severity and therefore billed at steeper prices, said John Hargraves, a researcher and co-author of the report.

The Washington, D.C.-based nonprofit group analyzed 40 million health-care claims for those with employer-sponsored plans between 2009 and 2016. The insurers included United HealthCare, Aetna and Humana.

“Since the population of insured people in emergency rooms is not changing, the only logical explanation is a change in how things are being coded,” Hargraves said.

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When a patient arrives at an emergency room — either a traditional one attached to a hospital or a free-standing emergency center located in a retail center — the visit is assigned a procedure code ranging from 1 to 5 for purposes of billing. Level 1 is the least serious, Level 5 is the highest. The way such designations are determined can be tricky and in the eye of the beholder depending on patient history, age and complexity of treatment.

Hargraves said his research focused only on the so-called facility fees, meaning the price charged by a hospital or emergency room center for providing the treatment setting. It did not look at the cost of actual treatment.

He found that over the eight-year period, the facility prices rose for all procedure codes but climbed fastest for those designated as the highest severity. The price of the highest coded visit rose to $1,108, from $627 in 2009. This is particularly significant, Hargraves said, because during the same time his group found there were many more claims being designated as 4s and 5s while the use of lower severity codes actually decreased.

According to the group’s data, the number of emergency room visits was statistically the same in both 2009 and 2016.

Texas was among states that had the highest bump in the use of high severity codes, with the use of 4s and 5s rising to 61 percent, up from about 50 percent in 2009.

The cost of emergency room care has become a hot button issue recently. In Texas the state’s largest insurer, Blue Cross and Blue Shield of Texas, wanted to roll out a controversial new program this month to create a vigorous after-the-fact review system to determine if health maintenance organization (HMO), policy holders were using emergency rooms appropriately. If it was determined they could have reasonably received treatment in a less expensive setting the insurer would pay zero.

But late last week Blue Cross and Blue Shield officials announced its launch would be delayed until early August as the Texas Department of Insurance sought more information and assurances that patients would not be harmed by the new policy. Physician groups and some consumer advocates are also worried that the Blue Cross program would have a chilling effect as people become afraid to get the care they need.

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Insurance executives have said the measure was designed to not only discourage inappropriate use of emergency rooms for non-emergency care but to also fight back against what it calls overtreatment and overbilling, including the practice of “up-coding” where the highest level of severity code is used for less serious patients.

Elsewhere in the country, Anthem, the insurance giant, has initiated a similar crack-down on emergency room claims in Kentucky, Missouri, Indiana, Ohio, New Hampshire and Connecticut.

jenny.deam@chron.com

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