A recent research report shows that Medicare ACOs are facing difficulty to control and manage patient care because most beneficiaries have unrestricted choice over choosing healthcare providers. Much of the specialty care received was provided outside the patients' assigned ACO. The potential challenges in outpatient care are: the proportion of patients assigned to an ACO in 1 year who remained assigned the next year

• The proportion of office visits outside a patient's contracting organization

• The proportion of Medicare outpatient spending billed by a contracting organization that is devoted to assigned patients.

For more details please visit Mark Crane’s article in this link: http://www.medscape.com/viewarticle/823951