A man stands outside the emergency room of Health Central Hospital in Occoee, Florida December 8, 2009. Credit: Reuters/Scott Audette

The survey contradicts a common perception that emergency rooms are packed with uninsured people and illegal immigrants. It also rejects some claims that people are using the emergency department for routine care -- just 10 percent of visits were for non-urgent causes.

In 2007, approximately one in five persons in the U.S. population had one or more emergency department visits in a 12-month period, the report from the National Center for Health Statistics reads.

Among the under-65 population, the uninsured were no more likely than the insured to have had at least one emergency department visit in a 12-month period.

Tamyra Carroll Garcia and colleagues at the center used two large national surveys of healthcare use in 2007 for their study.

Since 1996, demand for emergency services in the United States has been rising, they wrote.

While the number of emergency departments (EDs) across the country has decreased, the number of ED visits has increased. As a result, EDs are experiencing higher patient volume and overcrowding, and patients seeking care are experiencing longer wait times, they added.

As national health care costs continue to rise and policymakers become increasingly interested in ways to make the health care system more efficient, it is important to understand the characteristics of those individuals who use EDs -- often in place of other sources of ambulatory care.

They found that the more income people had, the less likely they were to ever visit an emergency room. People over 75 and blacks were the most likely to visit emergency rooms.

The American College of Emergency Physicians published a survey this month showing that 61 percent of emergency doctors surveyed believe U.S. healthcare reform will send even more people to emergency departments.

Only 1 percent of the 1,800 doctors surveyed thought visits would decrease. And 47 percent said the reforms signed into law in March would worsen overcrowding in emergency rooms.

It's important to note the report finds that having a usual source of medical care, such as a primary care provider, does not affect the number of times people under age 65 visit the emergency department, Dr. Angela Gardner, president of the American College of Emergency Physicians, said of Wednesday's report.

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