Do retail medical clinics boost medical spending?

From the Globe:

For the past decade and a half, people suffering from minor maladies such as earaches and sore throats have flocked to a low-cost, convenient place for treatment — clinics inside drugstores and department stores.

But a study published Monday suggests such convenience may come at a cost: Researchers found that retail clinics — Massachusetts has 58 — increase medical spending by attracting people who otherwise would have stayed home.