One in four privately insured adults said in a new poll that they doubt they could afford to pay costs associated with a major unexpected illness or injury.

Among the "plan-switchers" who changed insurance plans after Obamacare went into effect last year, 45 percent said they are now paying more, compared to 29 percent who said they are paying less.

The poll, conducted by the Associated Press-NORC Center for Public Affairs Research between July 22 and September 3 among 1,004 adults aged 18 to 64, found that the biggest financial worry comes from high-deductible plans requiring a large amount to be paid before insurance takes over.

"Such plans already represented a growing share of employer-sponsored coverage," said the Associated Press. "Now, they're also the mainstay of the new health insurance exchanges created by Obama's law."

One Pennsylvania man, Edward Frank, told the Associated Press that paying his monthly premiums in addition to his $6,000 deductible cost him more than it would to just "pay the bill outright."

The poll also found that 19 percent said they did not go to the doctor when they were sick or injured due to the costs, 17 percent skipped a recommended treatment, and 18 percent went without a physical exam or preventative care.

Only half of those polled said they had a strong understanding of what their Obamacare plans covered.

Due to the high costs, 33 percent said they cut back on entertainment as a way to compensate. That number rose to 43 percent when considering only those with high-deductible plans.

One government definition places the threshold for a high-deductible plan at $1,300, but deductibles for the popular silver plan on insurance exchanges average around $3,100 said the Associated Press.

The data highlights "why President Barack Obama faces such strong headwinds in trying to persuade the public that his health care law is holding down costs," said the Associated Press.

Results for the poll have a margin of sampling error of +/- 4.1 percentage points.