The vast majority of U.S. health system acquisitions in the next few years will continue to be vertical moves, with systems picking up retail centers, clinics and physician practices, according to a report by consulting firm Accenture.

"Health systems definitely want to move away from buying brick-and-mortar hospitals, where they see the sickest of their patients," said Kristin Ficery, managing director of health provider consulting at Accenture and author of the study Healthcare M&A: Mastering the 3D chessboard. "They need to own the various areas where patients enter the system."

The American Hospital Association views the move as part of the transformation of the health care system. "The shift in hospitals toward vertical integration is a response to the need to form new delivery system models that allow for greater coordination of care across the continuum, promote quality improvement by standardizing care pathways and support the management of population health," said a spokeswoman for the AHA.

One example of this strategy is the recently announced partnership between Providence Health & Services and Walgreens in Portland and Seattle, where the health system will integrate 25 store-based clinics into its primary care model.

In addition to lowering risk, improving cost structures and capturing more of the payer dollars, this kind of vertical integration lets health systems give customers what they want, where they want it, Ficery said.

"These are moves to have access to the very best clinicians in the community," she said. "And by owning across the continuum, a health system can serve the population in any way that they want."

The study also predicts a steep rise in purchasing and partnering with digital resources such as health care companies that deal with sensors, mobility, analytics or cloud capabilities. Digital acquisitions will expand by a multiple of eight, from 1 percent of overall acquisition volume in 2014 to 8 percent by 2018, the report states.  

"There are no guarantees of success but a portfolio approach will improve the chances that the broader business survives and grows and a transaction generates the value that was intended," Ficery adds.

Accenture analyzed more than 1,500 acquisitions from 2006 to 2014 for the report.