Thousands in Missouri and Kansans are among 5.2 million poor, uninsured adults who will fall into the “coverage gap,” created by 26 states choosing not to expand

Medicaid under the federal health reform law next year, according to a study released today by the Kaiser Family Foundation.

These people are projected to have incomes too high to qualify for their state’s existing Medicaid programs, but below the federal poverty level (nearly $11,500 for an individual) required to be eligible for tax subsidies to buy private coverage on the new insurance marketplaces set up by the Affordable Care Act, or ACA. Medicaid is the state-federal health insurance program for the poor.

“Millions of adults will remain outside the reach of the ACA and continue to have limited, if any, options for health coverage,” the study concludes.

The law provides full federal funding for three years to states that expand Medicaid to cover residents under 138 percent of the poverty level (or just under $15,900 for an individual).

But the Supreme Court made that requirement effectively optional for states, and most Republican led-states have opted against expanding the program.

There is no deadline by which states must opt to expand Medicaid, and a few states are still considering it.