* Poor neighborhoods less likely to have access

* Municipalities may want to offer incentives for clinics

While seen as a way to improve health-care access for the poor and uninsured, retail clinics in the United States tend to be clustered in higher-income neighborhoods, researchers said on Monday.

Located in grocery stores and retail chains such as Walgreen Co (WAG.N), CVS Caremark (CVS.N) and Wal-Mart Stores Inc (WMT.N), retail clinics offer convenient, walk-in hours for flu shots, treatment of sore throats and other basic services.

They have taken off since 2000, and there are now roughly 1,000 of them in the nation.

"Poorer neighborhoods are less likely to have access to these clinics," Dr. Craig Pollack of the University of Pennsylvania School of Medicine said in a statement following a study of 1,000 such clinics.

Using mapping software and Census data, Pollack and his colleagues found that the clinics were located in areas with a lower population of black residents, lower poverty rates, and higher median incomes than areas without retail clinics.

"They are significantly less likely to be located in poor or underserved neighborhoods," he added.

Although fiercely opposed by some U.S. physician groups, the clinics are showing signs of being integrated into the U.S. health system. Marquee hospital chains including the Cleveland Clinic in Ohio and Mayo Clinic in Minnesota have begun partnering with clinics run by Wal-Mart Stores.

Retail chain operators have said the clinics may improve access to care for uninsured or underserved people, and clinic operators and some doctors see them as a potential solution to a serious national shortage of primary care doctors.

Pollack said recent studies have suggested that the clinics are less costly than physician-based practices because they offer limited range of services, and they are also more likely to be used by people who do not have a regular doctor.

That may help those in poor areas who have less access to insurance and are less likely to see a regular doctor.

"By tending to locate in richer neighborhoods, retail clinics may not be meeting their full potential to help address these problems," he said.

Given the shortage of primary care doctors, Pollack said municipalities may want to consider offering incentives for clinics to open up in poorer, underserved neighborhoods.

Tine Hansen-Turton, executive director of the Convenient Care Association, an industry group that represents retail clinics, said the clinics were not devised to be part of the health care safety net.

"Convenient care clinics are niche providers, providing a relatively limited set of services in a manner that is cost-effective, transparent, and convenient, while maintaining a strong commitment to clinical quality," Hansen-Turton said in an e-mail.

But she added "there is a very real possibility" that clinics might expand to more populations and forge partnerships with state and local governments to treat more underserved patients.

Peter Miller, president and chief executive of Take Care Health Systems, which operates clinics in Walgreens pharmacies, said 20 to 30 percent of clinic customers pay in cash and are uninsured or underinsured.

Some 30 percent do not have a primary care provider, and more than 40 percent say if it were not for the clinic, they would have gone to an emergency department, an urgent care clinic or might not have sought treatment at all, he added.