Lawmakers andpatient advocacy groups have been pushing for legal changes toreduce surprise billing. (Photo: Shutterstock)

Out-of-network billing increased sharply between 2010 and 2016,according to a new study released by JAMA Internal Medicine.

In an analysis of 13.5 million emergency department admissions,researchers at Stanford found that patients were billed forservices outside of their insurance network 42.8 percent of thetime in 2016, up from only 32.3 percent six years earlier.

Out-of-network bills are nearly as common forinpatient admissions. Forty-two percent of the 5.5 millioninpatient services the researchers examined were out-of-network, upfrom only 26 percent in 2010.

Related: Out-of-network providers vex large employerplans

While it’s impossible to know exactly what each patient paid,the study noted that the average potential cost of eachout-of-network admission nearly tripled for ER visits, from $220 to$628. For inpatient admissions, it more than doubled, from $804 to$2,040.

“Out-of-network billing appears to have become common forprivately insured patients even when they seek treatment atin-network hospitals,” wrote Eric C. Sun and Michelle M. Mello.“The mean amounts billed appear to be sufficiently large that theymay create financial strain for a substantial proportion ofpatients.”

Lawmakers and patient advocacy groups have been pushing forlegal changes to reduce “surprise billing.” Anecdotes of patientsgoing to a hospital in their network but unknowingly being servedby a doctor outside of their network have prompted calls forgreater transparency from hospitals and limits on out-of-networkcharges.

A number of proposals in Congress aimed at curtailing surprisebilling have garnered bipartisan support. The Trump administrationhas indicated it would support legislation requiring doctors toprovide written notice to patients before assigning them to anout-of-network specialist.

While much of the ire is directed at providers, the rise insurprise bills is likely largely due to insurers offering narrownetworks that make it difficult for many members to find aphysician or specialist covered by their plan.

Read more: 

• What to do about surprise bills? It’s not soclear-cut.
• Time for federal action against balancebilling?
• Out-of-network providers vex large employerplans