All told, some 270 stakeholder groups signed a letter to members of Congress urging them to repeal the Independent Payment Advisory Board. The IPAB is a panel of experts, appointed by the president, that will have the power to cut Medicare payments.

The organizations represent doctors, other healthcare providers, employers, drug and medical device manufacturers and some disease-specific advocates — in short, a robust cross-section of the groups that stand to lose as a new and powerful body looks for Medicare savings.

"While we all recognize the need for more sustainable healthcare costs, we do not believe the IPAB is the way to, or will, accomplish this goal," the organizations wrote. Read More