Although more than 12 million Americans are enrolled in both Medicare and Medicaid, many enrolled individuals face challenges and issues arising from the program, according to a new report from KFF. 

"There are ongoing concerns about a lack of integration of services across the two programs that may contribute to fragmentation of care, poor outcomes and high costs," the report says. "In response to these concerns, federal and state lawmakers have been working to develop, test and implement a variety of coverage and financing options to improve coordination of care for this population."

Among dual-eligible individuals, Medicare is the primary source of insurance, while Medicaid provides supplemental coverage.