http://healthaffairs.org/blog/2016/06/07/the-ripple-effects-of-medicaid-expansion/

The 19 states that continue to decline federal funding to offer Medicaid coverage to more uninsured residents are missing out on more than just improvements to their uninsured and uncompensated care rates. In fact, the ability of providers in Medicaid expansion states to deliver care to their most vulnerable patients has notably improved.

Residents of Medicaid expansion states—both adults and children—are more likely to have insuranceand thus more likely to have a usual source of care and less likely to have unmet health care needs or problems paying medical bills. Furthermore, Medicaid expansion has helped the financial bottom line forsafety-net clinics and hospitals because more of their patients can afford to pay for their care.