45% of the uninsured population is out of the ACA's reach: KFF report

Five years of the Affordable Care Act have enabled millions of uninsured people to gain coverage, but for a number of reasons, that growth has now halted, according to Kaiser Family Foundation (KFF).

Much of the remaining uninsured population lies outside the law's reach—either because those people live in a state that refused to expand Medicaid or because their immigration status prevents them from full eligibility, KFF wrote in a report released Friday. Others are eligible for assistance from the ACA, but that assistance has proved insufficient for their needs.

"For the first time since passage of the law, the number of uninsured people increased in 2017, and 27.4 million remain uninsured," the organization wrote. "Nearly half (45%) of the remaining uninsured are outside the reach of the ACA either because their state did not expand Medicaid, they are subject to immigrant eligibility restrictions or their income makes them ineligible for financial assistance."

The ACA took a piecemeal approach to full coverage, covering different groups of people with different options depending on where they fell on an income scale. But the law's authors didn't count on the Supreme Court repealing the mandatory Medicaid expansion, leaving states with an option to back out.

Those that did left their newly Medicaid-eligible populations in the lurch—they made too much money to receive Medicaid sans expansion, and they didn't make enough money to be eligible for marketplace subsidies, according to the report.

Sources of coverage for the nonelderly under the ACA. (KFF)

In other words, a big chunk of the "ACA Medicaid Expansion" puzzle piece in the above graphic was removed, leaving a hole for that portion of the population.

RELATED: Rate of uninsured adults reaches 13.7%, highest in 4 years, Gallup finds

But that alone wouldn't cause the drop in insurance rates for 2017. The researchers said several actions by the Trump administration that year that could have stalled coverage gains, including:

"Ongoing debate about altering the ACA or limiting Medicaid to populations traditionally served by the program could lead to further loss of coverage and place more people in jeopardy of facing access barriers or financial strain due to being uninsured," KFF said in the report.

Despite these concerns, coverage declines on the ACA's exchanges were not as stark as some researchers feared. The Urban Institute also projects that 2019 is set for more stability than in past years when there was far more policy upheaval.