The final insult, he said, came when Michigan cut those payments by 8 percent last year to help close a gaping budget shortfall.

“My office manager was telling me to do this for a long time, and I resisted,” Dr. Sahouri said. “But after a while you realize that we’re really losing money on seeing those patients, not even breaking even. We were starting to lose more and more money, month after month.”

It has not taken long for communities like Flint to feel the downstream effects of a nationwide torrent of state cuts to Medicaid, the government insurance program for the poor and disabled. With states squeezing payments to providers even as the economy fuels explosive growth in enrollment, patients are finding it increasingly difficult to locate doctors and dentists who will accept their coverage. Inevitably, many defer care or wind up in hospital emergency rooms, which are required to take anyone in an urgent condition.

Mrs. Vliet, 53, who lives just outside Flint, has yet to find a replacement for Dr. Sahouri. “When you build a relationship, you want to stay with that doctor,” she said recently, her face gaunt from disease, and her head wrapped in a floral bandanna. “You don’t want to go from doctor to doctor to doctor and have strangers looking at you that don’t have a clue who you are.”

Image Rebecca and Jeoffrey Curtis searched for care for their son. In the process, they felt like “second-class citizens,” Ms. Curtis said. Credit... Stephen McGee for The New York Times

The inadequacy of Medicaid payments is severe enough that it has become a rare point of agreement in the health care debate between President Obama and Congressional Republicans. In a letter to Congress after their February health care meeting, Mr. Obama wrote that rates might need to rise if Democrats achieved their goal of extending Medicaid eligibility to 15 million uninsured Americans.