https://newsatjama.jama.com/2017/01/04/jama-forum-hospitals-dont-shift-costs-from-medicare-or-medicaid-to-private-insurers/

The Affordable Care Act (ACA) has allowed states to expand Medicaid. Medicaid pays hospitals prices that are lower than those paid by private insurers, although the price difference varies from state to state. Does this cause hospitals to charge private insurers even more to make up the difference, a cost shift?

Despite a substantial body of evidence to the contrary, many people believe hospitals shift costs in this way. For example, in 2014, Don George, MBA, the president and CEO of Blue Cross Blue Shield of Vermont wrote, “When government reimbursements are insufficient to cover the cost of the services a facility provides to Medicare or Medicaid beneficiaries, hospitals charge patients with private insurance enough to cover not only the cost of their services, but the shortfall created by government reimbursements as well.”

In truth, it’s been nearly 2 decades since any rigorous study has found evidence of substantial cost shifting. Recent work has found the opposite effect—when public programs pay hospitals less, so do private insurers. In a 2013 study published in Health Affairs, Chapin White, PhD, MPP, now a senior policy researcher at Rand Corporation, found that a 10% reduction in Medicare payments to hospitals was associated with a nearly 8% reduction in prices hospitals charge private insurers. Another study by him and Vivian Wu, PhD, now at the University of Southern California, published in Health Services Research in 2013, found that a reduction in hospital inpatient revenue from Medicare was associated with an even larger decline in total revenue, also suggesting hospitals cut prices charged to private payers.