Hospitals with the highest case mix index

A hospital’s case mix index (CMI) reflects the complexity of its patient population and the associated resources needed for their care.

What does a high CMI mean?

Many factors influence hospital case mix index such as a patient’s condition or overall health prior to their hospital stay, their diagnoses, and any procedures they may need during the course of their care.

Patients are classified into Medicare severity diagnosis-related groups (MS-DRGs) depending on case complexity and medical needs. The Definitive Healthcare HospitalView product uses the average of MS-DRG weights across inpatient claims to calculate a CMI.

Higher CMIs often result in higher reimbursement rates for hospitals. The Centers for Medicare and Medicaid Services (CMS) uses their own CMI calculations based on MS-DRGs and DRGs to determine reimbursement for Medicare and Medicaid beneficiaries.

For example, many of the top 20 hospitals on the list below specialize in spinal surgery, general or orthopedic surgery, or the heart, which can involve complicated patient procedures. Because they treat the most complex cases with potentially higher risk, the hospital may be reimbursed at a higher rate.

What is the national average case mix index for hospitals?

Definitive Healthcare calculates a case mix index value for more than 5,800 U.S. hospitals in our HospitalView product. The average CMI is 1.50, with a range of values from 0.56 to 5.15.

The following table lists the 20 highest case mix index hospitals. Results in this analysis are sourced from the Medicare Cost Report (MCR) and reflect the most recent 12-month interval tracked in our database. Only hospitals with more than 15 beds are included in the analysis.