In fact, Booz & Company, a consulting firm, predicts that 1,000 of the nation’s roughly 5,000 hospitals could seek out mergers in the next five to seven years.

“There’s immense logic for them to become large super-regional systems, even some national systems,” said David W. Johnson, a managing director for BMO Capital Markets, which advises nonprofit health systems. Some chains are merging to increase their size and their negotiating clout with insurers, while others are trying to reduce costs and improve care, he said.

Some economists and health insurance companies worry that the trend could raise health care costs.

“The rhetoric is all about efficiency,” said Karen Ignagni, the chief executive of America’s Health Insurance Plans, a trade group that represents insurers. “The reality is all about higher prices.”

Whatever the outcome, hospitals are merging faster and in greater numbers than they have in years. After holding steady through much of the 2000s, the number of deals doubled to 105 in 2012 from 50 in 2009, according to Irving Levin Associates, a health care research firm. That is still less than half the annual peak during the last merger wave, in the late 1990s, but Booz and others say this is only the beginning.

Hospital executives say they have little choice but to combine given the coming changes in the industry. Many hospitals are struggling with lower payments from the federal government and declining patient admissions. They are also being confronted with fundamental changes in how they are paid under the Affordable Care Act and by private insurers.