Possible changes to Medicare could come up in debate over how to raise the debt ceiling next week.
The need to increase the nation's borrowing limit combined with the ongoing government shutdown increase the likelihood that the two debates will be combined.
Speaker John Boehner (R-Ohio) and his allies are gauging support for a wider fiscal deal that could include entitlement changes that the White House has supported in the past, such as further means testing for Medicare beneficiaries.
Thorpe and Holtz-Eakin, the former Congressional Budget Office director, noted that ObamaCare makes $200 billion in cuts to Medicare Advantage and that the program sustained cuts in the 2012 "fiscal cliff" deal.
"We believe that these types of policies will have negative, short- and long-term consequences for beneficiaries because they do not account for the impact of integrated delivery system reform on quality, outcomes and cost," Thorpe and Holtz-Eakin wrote.