Insured, uninsured face access problems.

One in five Americans postponed or skipped needed medical care last year because of cost, insurance problems, or difficulty getting an appointment, according to a report from the Center for Studying Health System Change.

Researchers, who compared nationwide survey data from the years 2003 and 2007, found that the number of Americans who reported problems with access to health care increased dramatically during the intervening period. In 2007, more than 23 million individuals (8%) said that they went without needed medical care, compared with 13.5 million (5.2%) in 2003.

There were even more problems with delaying care. In 2007, 36 million (12.3%) reported that they delayed seeking care, compared with 23.5 million (8.4%) in 2003.

The most recent figures come from the 2007 Health Tracking Household Survey, a nationally representative sample of about 18,000 individuals. The earlier data are drawn from a similar survey with a sample size of about 47,000 individuals.

"The change is not only large, but it is widespread," Peter J. Cunningham, Ph.D., the lead author of the study and a senior fellow at the Center for Studying Health System Change, said during a press conference. "It's changing for a lot of people."

Specifically, the researchers found that access problems were increasingly affecting people with and without insurance. In 2007, about 20% of uninsured people and 11% of insured people reported delaying care. In addition, 17.5% of uninsured people and 6.3% of insured people reported unmet medical needs.

But while more uninsured people reported access problems, the rate of increase for unmet medical needs between 2003 and 2007 was higher among people who had insurance. Of the additional 9.5 million people who reported unmet needs between 2003 and 2007, 6.7 million had health insurance, Mr. Cunningham said.

The researchers also found greater unmet medical needs among individuals with fair or poor health and among children from families with lower incomes. For example, unmet medical needs increased from 11.9% in 2003 to 17% in 2007 for people who were in fair or poor health.

And researchers saw the gap in access to care between low- and higher-income children widen in 2007 after having been virtually eliminated in 2003 following expansions of the Medicaid and State Children's Health Insurance Programs. In 2003, 2.2% of children below 200% of poverty experienced unmet medical needs, the same percentage as those children whose family incomes were at 200% of poverty or higher. However, in 2007, 5.4% of children below 200% of poverty had unmet medical needs, compared with 2.9% of children at 200% of poverty or higher.

The most commonly cited reason for access problems continues to be cost. In 2007, 69% of people who decided to delay or forgo needed medical care said worries about cost were the reason, which was up from 65.2% in 2003. Among insured people, cost worries were cited by 60.8% of people in 2007, compared with 53.7% in 2003.

"Insured people are facing growing cost pressures," Mr. Cunningham said. "Financial barriers to care are no longer just a concern for the uninsured."

BY MARY ELLEN SCHNEIDER

New York Bureau