Armed with poster boards and hard numbers, health care advocates rallied at the State House Thursday against the expected repeal of the Affordable Care Act, which they said could mean loss of coverage for almost 500,000 Massachusetts residents.

In a state where 97 percent of the population is insured, health care consumers, union workers and providers warned of potential devastating health and economic impacts if Congress repeals the ACA without an adequate replacement.

Protesters said $52.4 billion that helps fund Medicaid — insurance for the poor — that has been earmarked for Massachusetts, could be at risk. MassHealth now insures 300,000 as a result of the ACA's Medicaid provision. The money also includes federal tax credits that enable more than 190,000 Massachusetts residents to afford their insurance

Loss of federal funding could also threaten hospitals and health care jobs across the state.

“We are coming together to make it clear that repealing the ACA without a viable replacement will create chaos across our entire health care system. It will place enormous strain on Massachusetts’ largest industry, costing jobs, hurting hospitals, and making it much harder for vulnerable children, seniors and families to access critical care," said Tyrék D. Lee, Sr., executive vice president of 1199SEIU United Healthcare Workers East, the group that helped organize the rally. 

Across the nation, the ACA repeal could cost hospitals more than $165 billion between 2018 and 2026, according to estimates by the Federation of American Hospitals.

“I work at a prominent hospital that is on the front lines of caring for low-income and vulnerable communities, and I have seen firsthand that access to affordable health insurance saves lives,” said Latia Holmes, a Boston resident and health care worker at Boston Medical Center. “Our patients depend on us to provide quality care to treat everything from chronic conditions like heart disease, to mental health issues and addictions to opioids. Taking away their insurance and cutting the critical funds our hospitals need to care for them will endanger our patients’ health and well-being. And it's just wrong.”

Republicans are expected to move to repeal the ACA — coined "Obamacare" — in the first days after President-elect Donald Trump takes office. The Trump administration has said no one will lose coverage, but they have not offered a plan for replacement of provisions that allow small business owners and low income residents to afford insurance.