RE: O/E Ratio
Formal Definition: Acute Care Admissions Mortality ratio is the APR-DRG risk-adjusted ratio of observed/expected deaths for acute inpatient admissions based on the benchmark. Results are compared to the "universe" for a standardized O/E mortality ratio (1.0).
A ratio of 1.0 means that a hospital's mortality is average in comparison to the Comparative Database (CDB).
Below 1.0 means that the mortality rate is lower than the average performance of the comparative group and above 1.0 means that the hospital's mortality is higher than the average performance of the comparative group/database.
Numerator: Observed deaths.
Denominator: Expected deaths.
Measurement Calculation: Numerator divided by denominator.
The O/E metric is driven by contribution of all inpatient cases (not just expired case) as all contribute to the compiled Risk of Mortality within the APR-DRG System. Each patient, regardless of discharge status, is an opportunity to add to the E (expected) value. The O value is the actual observed rate and the E value is derived by the mortality 'expected' which is a measurement of the acuity and manifestations of the comorbid conditions of each case.
Since most patients do not expire less of the E value is generated by the expired patients and more of the E value is generated by the patients who are discharged alive. Also, it is further important to capture the ROM is all patients because an expired patient and a discharged living patient in the same APR DRG and ROM subclass level have the exact same expected mortality rate and thus expected death value. There is a misconception that the E values of expired patients are somehow greater than those of living patients, which is not really true, other than they are more likely to end up in a higher ROM subclass. This is why it is important to code all inpatient encounters to capture all significant conditions, regardless of payor or outcome (expired).
Paul Evans, RHIA, CCS, CCS-P, CCDS
Manager, Regional Clinical Documentation & Coding Integrity
Sutter West Bay
633 Folsom St., 7th Floor, Office 7-044
San Francisco, CA 94107
Cell: 415.637.9002
Fax: 415.600.1325
Ofc: 415.600.3739
evanspx@sutterhealth.org
A ratio of 1.0 means that a hospital's mortality is average in comparison to the Comparative Database (CDB).
Below 1.0 means that the mortality rate is lower than the average performance of the comparative group and above 1.0 means that the hospital's mortality is higher than the average performance of the comparative group/database.
Numerator: Observed deaths.
Denominator: Expected deaths.
Measurement Calculation: Numerator divided by denominator.
The O/E metric is driven by contribution of all inpatient cases (not just expired case) as all contribute to the compiled Risk of Mortality within the APR-DRG System. Each patient, regardless of discharge status, is an opportunity to add to the E (expected) value. The O value is the actual observed rate and the E value is derived by the mortality 'expected' which is a measurement of the acuity and manifestations of the comorbid conditions of each case.
Since most patients do not expire less of the E value is generated by the expired patients and more of the E value is generated by the patients who are discharged alive. Also, it is further important to capture the ROM is all patients because an expired patient and a discharged living patient in the same APR DRG and ROM subclass level have the exact same expected mortality rate and thus expected death value. There is a misconception that the E values of expired patients are somehow greater than those of living patients, which is not really true, other than they are more likely to end up in a higher ROM subclass. This is why it is important to code all inpatient encounters to capture all significant conditions, regardless of payor or outcome (expired).
Paul Evans, RHIA, CCS, CCS-P, CCDS
Manager, Regional Clinical Documentation & Coding Integrity
Sutter West Bay
633 Folsom St., 7th Floor, Office 7-044
San Francisco, CA 94107
Cell: 415.637.9002
Fax: 415.600.1325
Ofc: 415.600.3739
evanspx@sutterhealth.org