Colorado is the first state to analyze whether hospital cost-shifting — often referred to as a “hidden tax” on health plans — dropped following Medicaid expansion. (Photo: Shutterstock)

The Medicaid expansion promoted by the Affordable Care Act was a boon for St. Mary's Medical Center, the largest hospital in western Colorado. Since 2014, the number of uninsured patients it served dropped by more than half, saving the nonprofit hospital more than $3 million a year.

But the Grand Junction hospital's prices did not go down.

“St. Mary's is still way too costly,” said Mike Stahl, CEO of Hilltop Community Resources, which provides insurance to about half of its nearly 600 employees and their families in western Colorado. “We are not seeing the decreases in our overall health bills that I believe the community overall should be feeling.”