Not so long ago mixing a shopping trip with a visit to the doctor might not have crossed most people's minds.
But the concept has caught on quickly.
Clinics located in drug stores, supermarket and retail stores are attracting a rapidly growing number of patients, according to a new study released Wednesday by research group the RAND Corporation.
Researchers found that visits to retail medical clinics increased four-fold from 2007 to 2009.
Visits reached 5.97 million in 2009, compared to 1.48 million in 2007.
The clinics still represent a small portion of outpatient medical care when compared to the estimated 117 million emergency room visits and 577 million visits to doctors' offices made each year.
The researchers found people are opting for the clinics out of convenience. You don't need an appointment and the clinics are open for long periods during the day.
More than 44 percent of visits to the clinics were on the weekend or other hours when doctor offices typically are closed, according to the study published online by the journal Health Affairs.
The clinics may also be attractive to the uninsured and those with high-deductible insurance plans because of the lower and more predictable costs.
The study found that the clinics are attracting more older patients with the proportion of patients over age 65 growing from 8 percent to 19 percent.
The clinics are offering more flu shots, vaccinations and other preventive care services.
RAND researchers said some doctors are critical of retail clinics because they believe it interferes with the patient relationship with a primary care physician.
Patients may have less of a reason to visit their primary care doctor, particulary as clinics are offering treatment of chronic illnesses, such as diabetes, asthma and high blood pressure, some doctors worry.
RAND researchers analyzed data from 2007 to 2009 obtained from the three largest retail clinic operators, which account for 81 percent of the clinics operated nationally. They compared it to data gathered from 2000 to 2006.
The clinics used in the study were MinuteClinic at CVS, TakeCare clinics at Walgreens and The Little Clinic at Kroger supermarkets.