Mississippi has the largest percentage of poor and uninsured people in the country — 13 percent. Willie Charles Carter, an unemployed 53-year-old whose most recent job was as a maintenance worker at a public school, has had problems with his leg since surgery last year.

His income is below Mississippi’s ceiling for Medicaid — which is about $3,000 a year — but he has no dependent children, so he does not qualify. And his income is too low to make him eligible for subsidies on the federal health exchange.

“You got to be almost dead before you can get Medicaid in Mississippi,” he said.

He does not know what he will do when the clinic where he goes for medical care, the Good Samaritan Health Center in Greenville, closes next month because of lack of funding.

“I’m scared all the time,” he said. “I just walk around here with faith in God to take care of me.”

The states that did not expand Medicaid have less generous safety nets: For adults with children, the median income limit for Medicaid is just under half of the federal poverty level — or about $5,600 a year for an individual — while in states that are expanding, it is above the poverty line, or about $12,200, according to the Kaiser Family Foundation. There is little or no coverage of childless adults in the states not expanding, Kaiser said.

The New York Times analysis excluded immigrants in the country illegally and those foreign-born residents who would not be eligible for benefits under Medicaid expansion. It included people who are uninsured even though they qualify for Medicaid in its current form.

Blacks are disproportionately affected, largely because more of them are poor and living in Southern states. In all, 6 out of 10 blacks live in the states not expanding Medicaid. In Mississippi, 56 percent of all poor and uninsured adults are black, though they account for just 38 percent of the population.

Dr. Aaron Shirley, a physician who has worked for better health care for blacks in Mississippi, said that the history of segregation and violence against blacks still informs the way people see one another, particularly in the South, making some whites reluctant to support programs that they believe benefit blacks.