WASHINGTON – Despite the rapid growth of retail clinics, only a tiny fraction of American families in 2007 used them, according to a national study released today by the Commonwealth Fund.

The number of retail clinics, typically located in pharmacies, supermarkets and big-box retailers, has grown rapidly in recent years, from about 60 in 18 states at the beginning of 2006 to more than 900 in 30 states by the end of 2007.

"While overall use of retail clinics remains modest, families with unmet medical needs tend to use the clinics more than the rest of the population," said Ha T. Tu, an HSC senior researcher and co-author of the study with Genna R. Cohen, an HSC health research assistant.

As of 2007, 2.3 percent of American families, or nearly 3.4 million families, have used a retail clinic, according to findings from HSC's 2007 Health Tracking Household Survey, a nationally representative survey with information on about 18,000 people in 9,400 families. The survey had a 43 percent response rate.

Of the families reporting using a retail clinic, about half reported visiting a retail clinic in the prior 12 months before the survey.

The study found that families that reported not getting or delaying needed medical care in the previous 12 months were almost 2.5 times as likely to have used a retail clinic as families without such access problems (1.9 percent vs. 0.8 percent). Also, younger families were more than twice as likely as older families to use a retail clinic.

"These findings suggest that retail health clinics have the potential to play a role in improving healthcare delivery, especially primary care," said Commonwealth Fund Vice President Anne-Marie Audet, MD.

A clinic's hours, locations and availability without appointment were major factors in choosing it over another source of care for many patients. Nearly half of all clinic users cited the low cost of a clinic visit relative to other care settings, and one in three cited not having a usual source of medical care, as major reasons for choosing clinics over other care settings.