Its flagship academic medical centers in Boston, Massachusetts General Hospital and Brigham and Women’s Hospital, anchor a health care hub that is arguably the best in the country, if not the world. Reimbursement rates from insurers are growing more slowly than expenses.

BOSTON - Mass General Brigham, the largest health care system in Massachusetts, announced layoffs Monday that will affect hundreds of workers, citing a $250 million projected budget gap.

Mass General Brigham attributed the layoffs to an expected budget shortfall of $250 billion over the next two years.

The layoffs could potentially impact employees at 12 hospitals under the MGB umbrella: While executives say the sweeping cuts are aimed at management and administrative-level employees with no impact on front-line workers, Boston University School of Public Health’s David Rosenbloom suspects the changes could reach patients.

Facing rising costs and hoping to make its sprawling network more efficient, the state’s largest private employer aims to cut payroll costs by over $200 million.

Mass General Brigham announced mass layoffs aimed to bridge a $250 million budget gap projected over the next two years in a letter to employees Monday — meaning potentially hundreds of