The number of retail health clinics that have been popping up in places like drugstores for years is expected to double by the end of 2015, according to the consulting firm Accenture.

Accenture said in a report released Wednesday that a flood of newly insured patients from the national healthcare overhaul will help stoke demand for those clinics, which typically treat minor illnesses when a patient doesn't have a doctor or the physician isn't available.

The overhaul is expected to expand health insurance coverage to nearly 30 million uninsured people. A big chunk of that growth will start next year when the state-federal Medicaid program for poor and disabled people expands in several states and the government starts offering income-based tax credits to help people buy insurance.

The clinics are expected to make access to care easier as the nation deals with this influx of newly insured patients and a primary-care doctor shortage. The clinics are generally open for longer hours than a doctor's office and on weekends.

They also can offer care at a lower cost than a doctor visit because they don't come with added expenses for equipment like x-ray machines that a typical physician's office might carry. They're also frequently staffed by nurse practitioners or physician assistants instead of doctors.

The price break can be attractive to patients who gain insurance coverage that requires them to pay a bigger slice of the bill than a typical $20 co-payment for an office visit.

"The theory is these settings can offer .... a set of primary care services in a consistent way at a lower price," said Dr. Kaveh Safavi, managing director for Accenture's North America health business.

Accenture PLC, which does not operate any clinics, forecasts that the U.S. clinic total will double from 1,418 at the end of 2012 to 2,868 in 2015.

These convenient care clinics started around 2000. National drugstore chains CVS Caremark Corp. and Walgreen Co. run most of them.

CVS has said it will have nearly 800 clinics by the end of this year and expects to run about 1,500 by 2017. Walgreen announced earlier this year that its clinics will expand the scope of care and start handling chronic diseases like diabetes, asthma and high blood pressure in addition to physicals or conditions like sinus infections.

Doctors have cautioned that these clinics can disrupt their relationships with patients and lead to fragmented care in part because a record of the clinic visit may not be transferred back to the doctor who is tracking the patient's health.

But Safavi said clinic operators are conscious of that issue and are investing in technology that allows them to share records. He also said he has seen no real evidence that these clinics present a risk to the quality of a patient's care.

"I think, generally speaking, the market place benefits from more choices at lower costs," he said.