People like to talk about disruptive change in the health care marketplace. Sometimes, though, game-changing business initiatives just creep quietly into the system without much fanfare but with plenty of potential punch. Take, for example, the growth of retail clinics. The first one opened in 2000. Now CVS has 700 locations and counting in 27 states and Walgreens has almost 400 sites. It may seem as though there is a Starbucks on every corner, but there probably is a retail drugstore every two blocks or so. One study estimated that 36 percent of the urban population lives within a 10-minute drive of a retail clinic. And the potential for expansion is enormous. Walgreens owns 8,117 stores and CVS has more than 7,500. CVS reportedly plans to open "at least" 100 new clinics in the next several years.

And people like them. They fill a major service gap. Ever had a kid with a painful earache on a Saturday at 4 p.m.? Well, you get the picture.

Actual statistics on number of visits are somewhat hard to find, perhaps because folks who keep tabs on such things don't consider them a serious part of the "system." A RAND Corp. study found that young adults — ages 18 to 44 — accounted for 43 percent of retail clinic patients. Another RAND study found that most retail clinics are located in metropolitan areas with lower poverty rates and higher median incomes.

Then, there is Walmart. Where does it fit? Walmart is not a big retail clinic success, but it can't be ruled out because, well, because it's Walmart. It tends to make big health care announcements and then falls silent. Last January, a company executive proclaimed that Walmart wanted to provide "full primary care services in five to seven years." Well, maybe.

The clinics, of course, would be located in Walmart stores. Where are most of these stores? They're in rural areas and underserved urban areas. So, between the drug chains in urban areas and Walmart in rural sites, that's pretty much the whole country.

A movement with lots of legs never stands still for long. Walgreens has formed partnerships with three ACOs, and announced new services to include "assessment, treatment and management" of chronic conditions, as well as new preventive health services.

The retail health care clinic revolution is pretty much a done deal. The clinics exist, people like them and they will get bigger and change over time. But there are other more nascent movements afoot with disruptive potential.

Want to know the future strategy of a company? Watch what they buy. Cigna, WellPoint and Humana all have purchased innovative, patient-centered companies, specializing not only in care coordination, but also intensive, personalized high-value chronic disease care while lowering cost.

Some companies are busy handing off employees to private health exchanges, but others are becoming much more hands-on. Many people know that Boeing, Walmart and Lowe's are direct contracting with health systems and pushing value and transparency. Many others are watching to see what happens and how they did it.

So, the next time you survey the health care marketplace and say, "Oh, I know them. They're a drugstore, or an insurance company, or a big employer," look again. They could be much more.

— Reach me at mgrayson@healthforum.com.