About one in 12 visits to in-network ambulatory surgery centers may result in a surprise medical bill from an out-of-network provider, according to a study published Wednesday in Health Affairs.
On average, the surprise medical bills would potentially have left patients on the hook for $1,141, the study found. Most of the time, the cases that could have resulted in a surprise bill involved an out-of-network anesthesiologist or registered nurse anesthetist.
"This is another common source of care for primarily elective procedures—things like cataract surgeries and orthopedic procedures," said Erin Trish, assistant professor at the University of Southern California and a co-author of the study. "As a consumer or patient, you really are strapped in the sense that you don't know how to find out in advance the network status of the anesthesiologist that's going to treat you. That's very concerning about the way this market works."
Ambulatory surgery centers have grown in prevalence over the past several decades and are a common place to receive elective care, as the cost is typically lower than in an inpatient hospital. According to the study, the number of ambulatory surgery centers grew from 1,000 in 1988 to 5,400 in 2015. But, like in other settings such as emergency departments, it's possible that a patient will unwittingly see an out-of-network physician even when the facility itself is in the patient's insurance network.
Surprise bills may occur when insurers do not pay the out-of-network providers' full charges, and the provider sends the patient a bill for the remaining balance. The patient may be on the hook for the provider's balance bill in addition to whatever cost-sharing the insurer required.
Researchers analyzed commercial claims data from UnitedHealth Group, Humana and Aetna for 3.3 million patients who visited ambulatory surgery centers from 2014 to 2017. The data came from the not-for-profit Health Care Cost Institute.
About 10% of 4.2 million episodes of care at the ambulatory surgery centers involved out-of-network providers treating patients at in-network surgery centers. Roughly 8% of episodes could have resulted in a surprise bill, they concluded.
Anesthesiologists generated the out-of-network bill in about 44% of cases, while nurse anesthetists represented a quarter of the cases.
The size of the surprise bills increased by 81% over the study period, from an average $819 in 2014 to $1,483 in 2017. Trish said ambulatory surgery centers see similar surprise billing rates as elective inpatient admissions, but lower rates than emergency department visits. Previous research has shown that one in five ED visits results in a surprise medical bill.
The Health Affairs study also found that when compared to fully insured plans, self-funded plans were more likely to pay providers' full billed charges, taking away the potential for a patient to receive a surprise bill. About a quarter of the time, self-funded plans paid the full charges.
"On the one hand that's good, because it protects the patient from receiving a surprise bill," Trish said. "But the kind of longer term or bigger picture implication is that it drives up healthcare spending for everyone, and we see that in the in the form of higher premiums."
The researchers pointed out that the study is limited in that there's no way to observe from the claims data whether or not the patients were actually sent a surprise medical bill. It's possible that in some cases, providers wrote off the charges instead of balance-billing a patient. Additionally, it's possible that some patients voluntarily chose to receive care from an out-of-network provider.