In the latest deal reshaping the business of health insurance, the nation’s largest insurer, UnitedHealth Group, announced Wednesday that it would buy a network of 300 primary care and specialist clinics from dialysis giant DaVita for $4.9 billion.

The deal, which does not include DaVita’s main kidney-care business, comes days after CVS Health agreed to buy health insurer Aetna for $69 billion. Both acquisitions reflect strategies to try to own major entry points into health care, whether it is primary care doctors or pharmacists, so that insurers can better coordinate care, keep people healthy and hopefully control rising costs.

“If you think about what Aetna and United are trying to do, basically they’re trying to own the quarterback of care,” said Brian Tanquilut, an equity analyst at investment firm Jefferies. “At the end of the day, the beauty of owning these practices is you have greater control over a person’s whole health-care picture.”

Each strategy is slightly different. United’s business segment, Optum, will acquire DaVita Medical Group, which includes 300 clinics that provide primary and specialist care, as well as urgent care centers and half a dozen surgery care centers. Those clinics serve 1.7 million patients each year in California, Colorado, Florida, Nevada, New Mexico and Washington. The acquisition, set to close next year, will expand the company’s move into clinics and surgical care centers.

In CVS’ case, the deal joins 9,700 brick-and-mortar pharmacies with Aetna’s 22 million medical members. The joint company plans to transform those locations into a primary access point for basic health care. The idea is that this nationwide network, including pharmacists and nurses, could help keep people well, managing chronic diseases before they become expensive emergencies and providing an alternative and cheaper venue for many kinds of basic health care.

Independent physicians have expressed reservations about the CVS deal, worrying that they may be cut out of the equation and patients might get worse care. Physicians and insurers also have a long history of being in conflict, as insurers’ efforts to manage costs by avoiding inappropriate or expensive care are sometimes seen by doctors as an attempt to overrule their medical judgment.

Zack Cooper, a health economist at Yale University, said those anxieties are to be expected.

“We spend close to 20 percent of GDP on health care, and most of us say that shouldn’t be the case. Any sorts of changes are going to create turbulence for people who are purveyors of the status quo,” Cooper said.

Cooper said these kinds of vertical mergers, among companies that don’t directly compete, don’t tend to give one firm the market power to raise prices the same way mergers between similar businesses do. Instead, he said both deals highlight new strategies aimed at reducing health-care costs.

There’s been a growing realization that high-deductible health plans that shift costs on to consumers are a blunt tool to try to decrease spending, because they often deter people from getting care instead of encouraging them to shop around.

The two deals represent companies exploring new ways to rein in costs, and the diversity in approaches shows that no one yet knows what will work.