Medicare payment for acute care hospital inpatient stays is based on set rates under Medicare Part A. The system for payment, known as the Inpatient Prospective Payment System (IPPS), categorizes cases into diagnoses-related groups (DRGs) that are weighted based on resources used to treat Medicare beneficiaries in those groups. The Centers for Medicare & Medicaid Services (CMS) updates the IPPS regulations annually, with comment periods open prior to implementation of the final rule.
AAPM&R IPPS Comment Letters
IPPS Final Rules