Sanders’s plan would actually add more financial stress on a certain group of poor Americans: those who are working and currently receiving Medicaid. This is because the Vermont senator plans to fund the single-payer plan with an increased payroll tax, reported the Washington Post. Therefore, poor workers will end up paying more for similar insurance coverage due to the additional 6.2% payroll tax levied on their paychecks that doesn’t exist today.

That would affect nearly 72% of all households enrolled in Medicaid, according to Kenneth Thorpe, the public health expert who conducted the study. Or, in hard number terms, nearly 14.5 million Medicaid beneficiaries would be worse off under Sanders’s proposed plan, says Thorpe. If the single-payer system costs more than Sanders estimated–which Thorpe says is likely, roughly to the tune of $1.1 trillion a year–then the total number of Medicaid recipients who are worse off grows to 16.8 million.

To be sure, there’s also a group of Americans who would benefit significantly from Sanders’s federally-funded health plan. An estimated 2.9 million poor adults in the U.S. are ineligible for Medicaid because some states didn’t expand the program, according to the Kaiser Family Foundation. Those same people also aren’t eligible for insurance subsidies under the Affordable Care Act because the law assumed they would be covered by an expanded state Medicaid program.

This also doesn’t take into account the families and adults for whom, even with subsidies, insurance is a major financial burden. To be eligible for Medicaid in states that expanded the program, a family of three mustn’t make more than $28,000 a year.

In response to the study, Warren Gunnels, Sanders’s policy director, told the Washington Post that the candidate’s health plan cannot be considered without the context of a $15 an hour minimum wage across the nation. The health care plan must be considered in tandem with better conditions for the working poor.