The reason for ER overuse is simple: Medicaid patients (like all insured patients) feel that their insurance card entitles them to health care anytime they want it. When office doctors aren’t available to provide it, they go to the hospital to get it.

But there’s a huge problem with expanding this mentality to ever more Americans, at least given the payment mechanisms in place for Medicaid.

Doctors aren’t available for Medicaid because it pays us poorly while highly restricting tests and treatments, including prescription drugs. Preventive services such as eye care, hearing and dental care are now being limited by most states. A 2013 study in Health Affairs revealed that only 67% of primary care doctors like me, and less than half of all specialists, accept Medicaid.

Even those doctors who do accept Medicaid are reluctant to do so, and many limit the number of Medicaid patients they will see. A 2008 Health Tracking Physician Survey showed that only 40% of physicians accept all Medicaid patients who seek appointments.