People who use the services of retail clinics as opposed to a physician’s office are more likely to be females, younger, have higher incomes, and be relatively free of chronic health conditions, a new study finds.

The study by Rand Corp. used data from 13.3 million commercially-insured people. It found at least 3.8 million enrollees made at least one clinic visit in 2007-2009.

"We identified 11 simple acute conditions that can be easily managed at a retail clinic," said J. Scott Ashwood, the study's lead author. "These conditions, which include upper respiratory infection, bronchitis, ear infection, flu, and conjunctivitis, were the most common seen at retail clinics."

The study, published in the American Journal of Managed Care, indicated several factors which could predicting the use of retail clinics, including:

Age: retail clinics were most frequented by patients between the ages of 18-44; those over the age of 65 were excluded from the study.

Gender: More females than males used retail clinics

Income: Those with a median income of $59,000 were more likely to use retail clinics than groups with lower incomes, according to area zip code data.

Health: individuals with chronic health conditions were less likely to use retail clinics.

The study found there was no link between retail clinic use and the number of primary care physicians in the community.

"It appears that those with a higher income place more value on their time, and will use clinics for convenience if they have a simple health issue such as a sore throat or earache," said Dr. Ateev Mehrotra, the study's senior author and an investigator at RAND and the University of Pittsburgh.

Researchers pointed out the care provided in retail clinics were 30-40 percent less expensive than similar care provided at a physician’s office, and 80 percent less expensive than care provided in the ER.

"If the growth in retail clinic visits that we noted represents substitution for other sources of care, then the increase in retail clinic use could lead to lower costs, However, if these visits represent new utilization or induced demand in other words, patents are seeking care when they would have otherwise stayed home then costs could increase. Answering these questions requires additional study," concluded Ashwood.