Case Mix Index
Encyclopedia
Case mix
index (CMI) is the average diagnosis-related group
weight for all of a hospital's Medicare
volume. It can be used to adjust the average cost per patient (or day) for a given hospital relative to the adjusted average cost for other hospitals by dividing the average cost per patient (or day) by the hospital's calculated CMI. The adjusted average cost per patient would reflect the charges reported for the types of cases treated in that year. If a hospital has a CMI greater than 1.00, their adjusted cost per patient or per day will be lowered and conversely if a hospital has a CMI less than 1.00, their adjusted cost will be higher.
A link to the 2009 spreadsheet of the CMI for all US providers is called FY 2009 Final Rule Case Mix Index at the HHS webpage http://www.cms.hhs.gov/AcuteInpatientPPS/IPPS2009/ItemDetail.asp?ItemID=CMS1221364
An analysis of that file shows that there are 3619 hospital records. The number of cases for the hospitals ranges from a low of 1 to a high of 36,282 cases at Florida Hospital in Orlando, FL (Medicare ID 100007). That hospital has a Case Mix Index of 1.57. The mean number of cases across all the hospitals in the database is 3,098 with a standard deviation of 3,102. As far as the Case Mix Index, the average is 1.37 with a minimum of .58 and a max of 3.73 and a standard deviation of 0.31.
A mix of cases in a hospital reflects the diversity, clinical complexity and the needs for resources in the population of patients in a hospital. Patients that have been treated in hospitals are classified in groups where other patients have the same condition, (based on main and secondary diagnosis, procedures, age) complexity (comorbidities) and needs. These groups are known as Diagnosis Related Groups (DRG) in the USA.
Case mix
The term Casemix refers to the type or mix of patients treated by a hospital or unit. The term is often used to describe the billing system of the hospital or unit, since the "cost per item" of healthcare is based on the casemix.-Background:...
index (CMI) is the average diagnosis-related group
Diagnosis-related group
Diagnosis-related group is a system to classify hospital cases into one of originally 467 groups. The 467th was "Ungroupable." The system of classification was developed as a collaborative project by Robert B Fetter, PhD of the Yale School of Management, and John D Thompson, MPH of the Yale...
weight for all of a hospital's Medicare
Medicare (United States)
Medicare is a social insurance program administered by the United States government, providing health insurance coverage to people who are aged 65 and over; to those who are under 65 and are permanently physically disabled or who have a congenital physical disability; or to those who meet other...
volume. It can be used to adjust the average cost per patient (or day) for a given hospital relative to the adjusted average cost for other hospitals by dividing the average cost per patient (or day) by the hospital's calculated CMI. The adjusted average cost per patient would reflect the charges reported for the types of cases treated in that year. If a hospital has a CMI greater than 1.00, their adjusted cost per patient or per day will be lowered and conversely if a hospital has a CMI less than 1.00, their adjusted cost will be higher.
A link to the 2009 spreadsheet of the CMI for all US providers is called FY 2009 Final Rule Case Mix Index at the HHS webpage http://www.cms.hhs.gov/AcuteInpatientPPS/IPPS2009/ItemDetail.asp?ItemID=CMS1221364
An analysis of that file shows that there are 3619 hospital records. The number of cases for the hospitals ranges from a low of 1 to a high of 36,282 cases at Florida Hospital in Orlando, FL (Medicare ID 100007). That hospital has a Case Mix Index of 1.57. The mean number of cases across all the hospitals in the database is 3,098 with a standard deviation of 3,102. As far as the Case Mix Index, the average is 1.37 with a minimum of .58 and a max of 3.73 and a standard deviation of 0.31.
A mix of cases in a hospital reflects the diversity, clinical complexity and the needs for resources in the population of patients in a hospital. Patients that have been treated in hospitals are classified in groups where other patients have the same condition, (based on main and secondary diagnosis, procedures, age) complexity (comorbidities) and needs. These groups are known as Diagnosis Related Groups (DRG) in the USA.