Retail clinics are proliferating rapidly, and are likely to take a significant share of primary care patients in the future, reports the Los Angeles Times. According to a study by the RAND Corporation of more than 13 million commercially insured patients, the number of patients who visited retail clinics on a monthly basis rose from 0.3 visits per 1,000 in 2007 to 2.7 visits per 1,000 in 2009. Those who are using the visits tend to be younger, healthier, and have relatively high incomes. Article