Information in this section summarizes billing statistics that effect DRG-based reimbursement and
may signal unexpected rates of complications, short stays, and other important measures.
Information is divided between Medical and Surgical admissions on the basis of DRG assignments.
Claims data are taken from the Medicare Provider Analysis and Review (MedPAR) file which is updated
annually by CMS based on the federal fiscal year. The MedPAR file includes billing data for 100% of
all Medicare fee-for-service claims (IPPS claims) for discharges during the twelve months ending
- MS-DRGs are defined as being either Medical or Surgical in nature. It is often helpful to
review these two categories of patients separately due to their fundamental differences.
- The CMI is the average relative weight for all cases reported in a period. MS-DRGs at lower
severity levels have lower relative weights and MS-DRGs at higher severity levels have higher
relative weights. The CMI provides a measure of severity.
- CC/MCC Rate
- The CC/MCC Rate is a measure of the incidence of complications (CCs) and major complications
(MCCs) within a period. The numerator is the number of patients with MS-DRGs defined by the
presence of a CC or MCC. The denominator is the total number of IPPS patients.
- MCC Rate
- The MCC Rate is a measure of the incidence of major complications (MCCs) within a period. The
numerator is the number of patients with MS-DRGs defined by the presence of an MCC. The denominator
is the total number of IPPS patients.
- Outlier Percentage
- Medicare IPPS patients that incur extraordinarily high costs are called "outliers" and are
eligible for additional payment. The number of outliers is reported as a percentage of total IPPS
patients. An unexpectedly high percentage could indicate a problem with clinical cost management,
cost reporting, etc.
- Short Stay Percentage
- Medicare IPPS patients with short stays may indicate premature discharges or inappropriate
admissions. The number of short stays is reported as a percentage of total IPPS patients. Short
stays are defined as patients who were discharged alive with a length of stay of 2 days or less.
- Acute Care Transfer Percentage
- Hospitals may be penalized for inappropriate transfers to another short-term acute care hospital
(STACH or CAH). The Acute Care Transfer Percentage reports the number of such transfers as a
percentage of total IPPS patients.