Even Americans with health insurance are piling up medical debt, according to a new analysis. 

One in three Americans with health coverage through their employer, the Affordable Care Act marketplace or the private market say they have medical debt that they are paying off over time, the Commonwealth Fund, a nonpartisan health policy research group, said in a report on Thursday. 

Hospital visits are the primary source of medical debt, with nearly two-thirds of U.S. adults reporting carrying debt related to such care. Patients also carry debt stemming from obtaining routine medical care, such as doctor’s office visits or getting lab or diagnostic tests, the study found. 

“The primary reason why these people have debt is about the extent to which their insurance covers their out-of-pocket costs,” Sara Collins, the study’s lead author and a health economist at the Commonwealth Fund, told CBS News.

“Unable to pay”

Almost half of Americans with medical debt, which amounts to about 15% of all working-age, privately insured adults, owe at least $2,000, according to the survey. To pay those bills, 37% said they drained their savings, while 30% reported cutting back on essentials like food, heat or rent, according to the Commonwealth Fund. Thirty percent also reported delaying or forgoing medical care. 

“Most Americans don’t have a lot of extra cash lying around, and when they are hit with an unexpected expense in a month when their income is allocated across all necessities of life, it can push people into medical debt they are unable to pay,” Collins said. “Especially among people who are low-income, they are on pretty regimented household budgets, and medical bills can really tip that budget over into the realm of not being able to pay for certain things and having to cut back.”

The findings were based on a telephone and online survey with a nationally representative sample of 6,353 adults.

There are some steps people with heavy medical debt can take to seek relief, Collins told CBS News. For example, healthcare providers may send a bill with erroneous charges, which the consumer should dispute if they believe the charges were a mistake. 

Some consumers are hesitant to do so, for fear that failing to pay will hurt their credit scores, Collins noted. “It’s a tough situation to be in, but it’s important to make sure what you are being asked to pay is correct.”

When coverage for medical services is denied, people can also contact their insurers and healthcare providers to negotiate a payment plan that lowers their out-of-pocket expenses.