The Obama administration needs to rewrite its accountable care organization rules to make them more palatable to providers and more widely adopted, seven Republican senators wrote in a letter to HHS officials Tuesday.

“An ACO model that can increase provider coordination and patient accountability would be a step in the right direction compared to today's fragmented delivery system,” wrote the senators, including Mike Enzi (R-Wyo.) to HHS Secretary Kathleen Sebelius and CMS Administrator Dr. Donald Berwick. “However, it is increasingly clear that this proposed rule misses the target.”

Among the problems with the ACO rules issued in March that the senators identified are misaligned incentives and accountability, as well as an uncertain return on investment for healthcare providers.

The Republicans highlighted various healthcare providers that have raised concerns about the ACO rules, including the American Hospital Association, which released a mid-May study that estimated six to 14 times higher start-up costs for the new entities than the CMS estimated.

The other Republican signatories were Sens. Jon Kyl (Ariz.), Tom Coburn (Okla.), Mike Crapo (Idaho), John Cornyn (Texas), Pat Roberts (Kansas) and Richard Burr (N.C.).