According to the 2009 Final OPPS Rule, the meanings of "new" and "established" pertain to whether or not the patient has been registered as an inpatient or outpatient of the hospital within the past 3 years.

A patient who has been registered as an inpatient or outpatient of the hospital within the 3 years prior to the visit would be considered to be an established patient for that visit, while a patient who has not been registered as an inpatient or outpatient of the hospital within the 3 years prior to the visit would be a new patient for that visit.

For example, if a patient was seen in the hospital's clinic or emergency department (either onsite or provider-based) within the past 3 years, that patient would be established on a future visit. However, if the off-site clinic was not provider-based, the patient's encounter would never attribute to the patient's future status.