In 1977, the program was transferred from administration by the Social Security Administration to the Health Care Financing Administration (HCFA), which is now responsible for establishing and enforcing the regulation for the program.
HCFA is responsible for auditing the records of health care providers who have received program dollars to ensure they are both billing for the appropriate amount and are providing adequate levels of care to Medicare patients.
In an effort to alleviate this problem the Health Care Financing Administration (HCFA) created Medicare Part D.
HCFA guidelines only allow you to change plans once a year, during the annual open enrollment period.
While HCFA oversees the program, private health insurance companies administer the plan.