WASHINGTON (AP) — Having health insurance is no panacea for high medical costs. Overall, 1 in 4 privately insured U.S. adults say they don't have much confidence in their ability to pay for a major, unexpected medical expense.

A new poll from The Associated Press-NORC Center for Public Affairs Research may help explain why President Barack Obama faces such strong headwinds in trying to persuade the public that his health care law is working to hold costs down.

The poll found the biggest financial concerns were among people with so-called high-deductible plans that require patients to pay a significant share of their medical bills each year before insurance kicks in.

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

Edward Frank of Reynoldsville, Pennsylvania, said he bought a plan with a $6,000 deductible last year through HealthCare.gov. That's in the high range, since deductibles for popular silver plans on the insurance exchanges average about $3,100— still a lot.

"Unless you get desperately ill and in the hospital for weeks, it's going to cost you more to have this plan and pay the premiums than to pay the bill just outright," said Frank, who ended up paying $4,000 of his own money this spring for treatment of shoulder pain.

"The deductibles are so high, you don't get much of anything out of it," said Frank, who is in 50s and looking for a new job.

The poll found that people are responding to the hit on their wallets in ways that may not help their health:

— Nineteen percent of all privately insured adults said they did not go to the doctor when they were sick or injured, because of costs. Among those with high-deductible plans, the figure was 29 percent.

— Seventeen percent skipped a recommended test or treatment; it was 23 percent among those with high-deductible plans.

— Eighteen percent of all adults went without a physical exam or other preventive care, 24 percent among those with high-deductible plans.

Sandra Chapman, a warehouse worker from Memphis, said she had to go without cholesterol medication last year because of issues with her prescription coverage. Instead of taking pills, she changed her diet.

"They only cover certain stuff and, I don't know, the rules change all the time," said Chapman, in her early 30s.

Health and Human Services Secretary Sylvia Mathews Burwell said last week that part of the problem is that many consumers don't understand what they are buying when they purchase health insurance, or how to use their plan once they get their cards in the mail.

For example, there should be no reason to skip routine preventive care, since the health care law requires insurers to provide it at no charge to the patient.

"People need to understand how to use their health care," said Burwell. "We need to spend time educating people."

Only about half of those surveyed said they had a strong understanding of what their plans cover.

Consumers sometimes pick health insurance based on the monthly premium alone. But low-premium plans have higher deductibles and other out-of-pocket costs. People who expect to be going to the doctor can come out ahead financially by paying higher premiums for a plan that features lower out-of-pocket costs.

Indeed, the poll showed that a majority of those with private insurance, 52 percent, would rather pay a higher premium and limit out-of-pocket costs than lower their premiums and potentially face higher out-of-pocket charges.

Many consumers said they are making financial trade-offs to pay medical bills:

—Overall, 33 percent said they cut back on entertainment; it was 43 percent among those with high-deductible plans.

—18 percent said they used up all or most of their savings, 24 percent among those with high-deductible plans.

—19 percent said they dialed down their contributions for retirement savings, 28 percent for people with high-deductible plans.

One government definition sets the threshold for a high-deductible plan at $1,300 for individual coverage, but in practice annual deductibles of $2,000 and even much higher are common.

Some people pair a high-deductible plan with a tax-sheltered savings account to pay their out-of-pocket costs — the poll found 40 percent who say they have high-deductible plans also have such an account. On the insurance exchanges, low-income people can receive additional help from the government for their cost-sharing expenses.

In another potentially troublesome finding for the White House, the poll found signs of dissatisfaction among people who changed plans in the last year, as the president's health overhaul went into full effect.

Plan-switchers who said they are paying more outnumbered those who are paying less by 45 percent to 29 percent. Of those paying more, 11 percent said they are getting higher-quality care for their dollar.

The AP-NORC Center survey was conducted with financial support from the Robert Wood Johnson Foundation.

The telephone poll conducted between July 22 and September 3 included interviews with a random national sample of 1,004 privately insured adults aged 18 to 64. Results for the full survey have a margin of sampling error of plus or minus 4.1 percentage points. It is larger for subgroups.

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