Walgreens’ decision to sell its pharmacy benefits management business to Catalyst Health Solutions for $525 million is sure to intensify the debate about whether drug chains are well served by owning and operating such entities.

For Walgreens, at least, the answer is clearly no. The retailer’s homegrown PBM is not insignificant, administering prescription drug coverage for some 11 million patients, but it lags far behind the big three in the field — Medco Health Solutions, CVS Caremark and Express Scripts.

The divestiture will allow Walgreens to concentrate on leveraging its store base, which president and chief executive officer Greg Wasson characterizes as “our center of gravity,” to enhance its ability to meet the health and daily living needs of consumers.

Those skeptical about the value of pharmacy/PBM combinations, including some financial analysts, have seized on Walgreens’ move to bolster their opposition to CVS maintaining its considerable stake in pharmacy benefits management. They point to the drag that the PBM division has had on earnings of late.

While the loss of several large PBM contracts has taken a toll on the company’s results and the benefits of the $26.5 billion merger that brought CVS and Caremark together in 2007 have taken longer to materialize than anticipated, there are compelling reasons to persist.

The company has a dominant position in the PBM market, managing drug coverage for approximately 60 million individuals, and Caremark accounted for almost half of CVS Caremark’s $96.41 billion in revenue in fiscal 2010. The PBM clearly has the scale to compete effectively.

More important, the nation’s health care system is in the midst of a period of fundamental change. If the reform process follows the pattern laid out in the Affordable Care Act — something that is far from certain in light of ongoing legal and legislative opposition to the measure — conditions for more closely integrated patient care will emerge. That bodes well for the broader continuum of pharmacy care that CVS Caremark is working to create.