Lead author J. Scott Ashwood of the Rand Corp. and colleagues analyzed commercial insurance claims from a population of 13.3 million patients in 22 markets from 2007 to 2009.
The study, published in the American Journal of Managed Care, found proximity to a retail clinic was the strongest predictor of use. Patients living within 1 mile of a retail clinic were 7.5 percent more likely to use one than those living 10 to 20 miles away.
The clientele of the retail clinic is most often young women with high incomes without a chronic condition. There was no association between primary care physicians availability and retail clinic use, the study indicated.
"If these trends continue, health plans will see a dramatic increase in retail clinic utilization," Ashwood said in a statement. "While use is increasing on average, it is particularly increasing among young, healthy, and higher income patients living close to retail clinics."