The problem is likely to grow, researchers say, as more people go on Medicaid as part of national healthcare reform. So simply expanding coverage may not be enough to improve low-income Americans' access to primary care.

"Insurance coverage does not necessarily mean better access," said senior researcher Dr. Adit A. Ginde, of the University of Colorado School of Medicine.

The study found that of more than 230,000 Americans surveyed over a decade, Medicaid recipients had more problems getting an appointment with a primary care doctor.

Just over 16 percent reported at least one "barrier" -- like having to wait too long for an appointment, limited health clinic hours, or even being unable to get someone on the phone at the doctor's office.

That compared with 9 percent of survey respondents who had private insurance.

HEADING TO THE ER

It's not surprising that Medicaid patients faced more obstacles, according to Ginde.

"We've known that Medicaid patients have more difficulty getting timely primary care," he said in an interview.

But the findings also show that when Medicaid patients can't get routine primary care, they are more likely to head to the ER.

Of Medicaid recipients who reported obstacles, one-half to two-thirds had more than one ER trip in the past year. That compared with 36 percent of Medicaid patients who reported no problems getting primary care -- and just 17 percent of their privately insured counterparts.

Even when people with private insurance had problems getting a doctor's appointment, they were much less likely than their Medicaid counterparts to end up in the ER.

Obviously, true emergencies warrant a trip to the ER, Ginde said.

But if people head there for problems that could have been taken care of in a doctor's office or health clinic, it becomes a huge expense.

"Especially if people take an ambulance," Ginde said. He noted that transportation problems were among the barriers to primary care that Medicaid patients cited.

"It's easy to blame the individual patient" for unnecessary ER visits, Ginde said. But if someone has worrying symptoms, like trouble breathing or a high fever, he said, "you can't expect them to sit at home for days and figure out how to manage it."

"It's a systems-level issue," Ginde said.

TOUGH TO TAKE TIME OFF

The study, which appears in the Annals of Emergency Medicine, included 230,258 Americans who responded to a federal health survey over 10 years. Just under 25,000 were on Medicaid, while the rest were privately insured.

There are a number of reasons why it's harder for Medicaid patients to get a timely appointment. One is that some primary care doctors don't accept Medicaid patients, while others take only a limited number.

Medicaid reimbursements are lower, Ginde noted, so doctors may limit the number of patients they'll take in order to "survive financially."

Then there are the limited business hours at many doctor's offices or clinics. "Those hours disproportionately affect Medicaid patients," Ginde said. "They're the working poor, and may not be able to take time off."

There are some potential fixes. In 2013 and 2014, Medicaid reimbursements will go up, to match those of Medicare -- the government health insurance program for older Americans. Right now, Medicaid reimburses doctors at 70 percent of Medicare rates.

That's aimed at giving doctors an incentive to accept the "expected flood" of new Medicaid patients. But for now, the higher reimbursement rate is a temporary measure.

Healthcare reform will also boost funding for so-called community health centers, which are designed to give low-income Americans a "medical home."

If those funds are used to expand centers' operating hours, for example, it could help more Medicaid patients get timely primary care, according to Ginde.

Some state Medicaid programs have taken controversial steps to prevent "unnecessary" ER trips -- like limiting the types of diagnoses it will cover if a patient goes to the ER.

But even if an injury or illness is not an emergency, there are many conditions that need timely attention, Ginde said. So Medicaid recipients need somewhere to go.

"The problem may actually get worse," he noted, "if we keep working with the same resources, but the demand increases."

SOURCE: bit.ly/HcT0Iw Annals of Emergency Medicine, online March 13, 2012.

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