A spate of hospital deals stands to further remake the U.S. health-care landscape, pushing up prices for consumers and insurers and changing how individuals get care.

Just this month, health systems with at least 166 hospitals and $39 billion in combined annual revenue have announced merger plans. There's likely more to come: The Wall Street Journal reported on Sunday that Ascension and Providence St. Joseph Health, a pair of nonprofits that together have 191 hospitals and nearly $45 billion in annual revenue, are in deal talks.

A fast-moving shakeout in the health-care sector has led to once-unorthodox deals across formerly distinct corners of the industry, as large insurers shift their business models amid pressure to bring down costs. That in turn has led hospitals to look for ways to preserve their revenues.