Healthcare advocates in Arizona are sounding the alarm over the GOP’s proposed replacement for the Affordable Care Act.

While the American Health Care Act is only beginning to work its way through Congress, the fallout for the state’s Medicaid program could be particularly severe. More than 400,000 people have joined the rolls since the state restored eligibility for some groups and expanded the program under the ACA.

The proposed Republican bill would end the enhanced federal funding for that expansion within a few years.

Kurt Sheppard, CEO of community health center Valle del Sol, warns that could again mean people coming in for care without insurance.

“Somebody’s going to pay for that. If it’s not Medicaid, taxpayers, someone…the cost and need don’t go away,” Sheppard said.

Nearly 80,000 children are also included in the Medicaid expansion category. While the individuals who are currently enrolled under the expansion would be grandfathered in at the enhanced funding rate, Dana Wolfe Naimark of Children’s Action Alliance said that will ultimately result in fewer people being covered.

“People tend to churn on and off Medicaid coverage because of their life circumstances. They might earn more money through overtime and lose their eligibility,” Naimark said. “As new people come to apply, they will not be covered with any federal funding.”

The bill would also change the funding model to a per-capita cap based on 2016 funding levels, which could hurt Arizona because it already runs a low-cost, efficient program.

If unexpected costs come up, Naimark said the state will be forced to make some tough decisions.

“What will happen for sure is some people will lose coverage, some people will get frozen out, certain services won’t be covered,” Naimark said. She points to the recession when state lawmakers in Arizona froze eligibility for certain groups.

Arizonans could see a more expensive marketplace under the Republican proposal, as well.

The average person enrolled in Arizona could see a big decrease in the tax credit that helps pay for insurance in the individual marketplace.

The structure of that credit is much different than under the ACA, and it’s also static across the country. So for example, a 45-year-old making about $22,000 would see their premiums go up about 340 percent.

If that person bought the same plan in New Mexico, Allen Gjersvig of the Arizona Alliance for Community Health Centers said “You’d get a 16 percent net increase, so the inequity it is going to create among states is going to be enormous."

Gjersvig said many Arizonans may just end up not buying insurance.

Gov. Doug Ducey hasn’t said much about the proposal, but has previously stated he doesn’t want to see hundreds of thousands of people lose coverage.