A new Kaiser Family Foundation brief finds that, among people with employer-based coverage, almost one in five patients admitted to the hospital end up getting a bill from an out-of-network provider.

Why it matters: Patients have to pay more out of their own pockets for out-of-network care.

• As a lot of excellent recent reporting on emergency room billing has shown, it can be almost impossible to avoid out-of-network bills even when you take pains to ensure you're going to an in-network hospital.

Balance billing — the practice of providers billing patients for the difference between their charges and insurance payments — is often responsible for these situations.

• The Affordable Care Act required private plans to limit annual cost-sharing, but these generally only apply to in-network service charges.
• Patients with emergency room claims and psychological/substance abuse claims are more at risk of receiving an out-of-network provider claim, per Kaiser.

By the numbers: For inpatient admissions, those who use in-network facilities still receive a claim from an out-of-network provider 15.4% of the time.