Thousands of working-age adults in Arkansas lost their Medicaid coverage as a result of new work requirements that didn't end up boosting employment, according to a new study published in the New England Journal of Medicine on Wednesday.

Arkansas is the first state to impose a work requirement for Medicaid, the federal program that has provided free health insurance to low-income Americans for more than five decades.

The study from Harvard University researchers could weaken one of the Trump administration's main arguments as it pushes states to enact new work mandates for Medicaid beneficiaries.

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Thousands of working-age adults in Arkansas lost their Medicaid coverage as a result of new work requirements that failed to boost employment, according to a new study published in the New England Journal of Medicine on Wednesday.

The study from Harvard University researchers undermines one of the Trump administration's main arguments as it pushes states to enact new work mandates for Medicaid beneficiaries. The administration says that imposing the mandates will encourage people to find work and be self-sufficient, lifting them out of poverty. And its casted Arkansas as a model for the nation.

Arkansas is the first state to impose a work requirement for Medicaid, the federal program that has provided free health insurance to low-income Americans for more than five decades. The state's rules targeted adults between 30 and 49 years old. It required that Medicaid's beneficiaries report 80 hours of work or completed activities like volunteering per month.

The Trump administration has approved similar proposals in eight states and six more have applied. The Arkansas rules, however, were tossed out by a federal judge in March. The administration is appealing the ruling.

Medicaid advocates oppose the Trump administration's efforts to restructure the government health program, warning that it will lead to large coverage losses. In Arkansas, over 18,000 people lost their Medicaid coverage, according to state data. The researchers found there was no sign that many of those who lost access to Medicaid had secured jobs or had access to other health coverage.

Read more: The Trump administration just opened the door to an enourmous change to Medicaid

The study also suggested that confusion over the mandate and bureaucratic obstacles led to the decrease of people enrolled in Medicaid.

"The idea of work requirements is to get people into new jobs and private insurance. But in our study that didn't happen," said Dr. Benjamin Sommers, lead author of the study, in a press release. "We didn't find any employment changes and instead we see Medicaid coverage rates dropping and more people without health insurance – usually because the process itself was confusing or beneficiaries didn't even know about the new requirements."

Arkansas public health officials disputed elements of the study, Politico reported. A spokesperson for the state's Department of Human Services said it wasn't "a meaningful or through evaluation" since it surveyed less than a year's worth of data.

In early 2018, the Centers for Medicaid and Medicare Services issued new guidelines allowing states to enact rules compelling individuals benefitting from Medicaid to be employed in some form. Administrator Seema Verma has been a strong advocate for the Medicaid work requirement.

But there were early warning signs that the mandate in Arkansas was causing people to lose government health coverage. Last September, the New York Times reported that 4,350 people had fallen off the Medicaid rolls as Arkansas began rolling out the changes. The state expected to save $30 million per year as a result.