In a finding that contradicts previous data, the cost to Medicare is lower when nurse practitioners rather than physicians provide primary care, says a new study.

Researchers from Mathematica Policy Research, Brandeis University’s Heller School for Social Policy and Management, and Montana State University who studied national data over a 12-month period found the cost was the same, or less, when nurse practitioners provided primary care compared with when physicians offered the services. The cost difference ranged from 11 to 29 percent. This contradicts earlier research that suggested the costs for nurse practitioners would be the same or even higher.

Policymakers have been increasingly concerned with the growing costs to Medicare as enrollment expands with the aging of the American population.