Starting in April, Colorado will see the largest shift in how people get their health insurance since the Affordable Care Act took effect in 2014.

About 325,000 people in Colorado are expected to be disenrolled from Medicaid as federal rules requiring states to keep them on during the COVID-19 public health emergency come to an end, said Kim Bimestefer, executive director of the Colorado Department of Health Care Policy and Financing.

That’s comparable to the 400,000 people who joined Medicaid in the first two years of its expansion to slightly higher-income groups in 2014 and 2015, she said.

It’s just one of a series of changes coming this year as the federal government’s COVID-19 public health emergency — and the expansions of social programs that came with it — comes to an end.

Other changes will affect how people pay for COVID-19 vaccines and testing, how much hospitals receive for treating some patients with the virus and whether people who were prescribed controlled substances online need to find an in-person medical home.

On Monday, the Biden administration announced the public health emergency will end May 11. While the emergency declaration is often linked in people’s minds to restrictions meant to slow the virus’ spread, almost all of the federal and state rules meant to control transmission are already gone.

Representatives for physicians, hospitals and groups focused on patient costs all listed the end of extended Medicaid coverage as the most disruptive change as the federal government winds down its pandemic response.

In most cases, members will lose eligibility because their income increased above Medicaid’s limit. Others moved out of state, or exhausted their one year of postpartum coverage.

Late last year, Congress decoupled the requirement that states keep residents on Medicaid from the public health emergency, meaning they could start removing those deemed ineligible as of April 1 even if Biden hadn’t moved to end the emergency.

The Kaiser Family Foundation estimated about 14 million people could be disenrolled nationwide, though some of them likely will return to Medicaid by the end of the year. Some of the people who lose coverage likely will be eligible, but won’t know they need to submit paperwork to maintain their coverage.

Bimestefer said anyone who is receiving Medicaid needs to make sure their contact information is up to date, so they get the paperwork to prove their eligibility. The plan is for members to receive a notice more than two months before their enrollment anniversary, which is when the department will determine if they still qualify, she said.

“We really want people to know this is coming,” she said. “We want to keep them covered on another (type of insurance) policy.”

The income limit for Medicaid coverage is $19,392 for an individual and $39,900 for a family of four. Some families that don’t qualify for Medicaid may be able to insure their children under the state’s Child Health Plan Plus program, which allows up to $79,500 in income for a family of four.

In the four years before the pandemic, an average of 65% of people who were removed from Medicaid were uninsured for at least a short time, according to a study from the Kaiser Family Foundation. About 41% of all people who were disenrolled later returned to Medicaid within a year.

The Department of Health Care Policy and Financing has an education campaign to let people who lose Medicaid know they likely will be eligible for tax credits to purchase insurance on the marketplace, and that they need to plan for higher out-of-pocket costs with commercial insurance, Bimestefer said. It also got permission from the Centers for Medicare and Medicaid Services to take other steps, like accepting forwarding addresses from the U.S. Postal Service as proof that someone still lives in the state.