CMS introduced the inpatient-only (IPO) list in 2001 to ensure patients who undergo complex, high-risk surgical procedures receive postoperative monitoring services in an inpatient setting.
The IPO list is routinely updated, and it is published annually in the Outpatient Prospective Payment System (OPPS) final rule. Although the list is usually made active in January, healthcare providers can view it a couple of months earlier in November when the OPPS final rule is published. The first IPO list had 300 procedures, but that number has grown to 1,700 in 2023.