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Healthcare Insights

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 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 25 hospitals on the list above 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.

The following table lists the 25 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.

Top 25 hospitals by highest case mix index

RankDefinitive IDHospital nameLocationCase mix indexExplore dataset
1552489Nebraska Spine HospitalOmaha, NE5.35Explore
21561Ascentist Hospital (AKA Doctors Hospital LLC)Leawood, KS5.29Explore
33321Oklahoma Spine HospitalOklahoma City, OK4.55Explore
44164Northwest Hills Surgical Hospital (AKA Austin Surgery Center)Austin, TX4.39Explore
51738Specialists Hospital ShreveportShreveport, LA4.38Explore
6776981Mercy Specialty Hospital - Southeast Kansas (AKA Premier Surgical Institute)Galena, KS4.21Explore
73332HPI Northwest Surgical HospitalOklahoma City, OK4.17Explore
81756The Spine Hospital of Louisiana at the NeuroMedical Center (FKA the Neuromedical Center Surgical Hospital)Baton Rouge, LA4.03Explore
93744Ascension Saint Thomas Hospital for Specialty Surgery (FKA the Hospital for Spinal Surgery)Nashville, TN3.98Explore
10274123OrthoColorado HospitalLakewood, CO3.94Explore
113901Baylor Scott & White the Heart Hospital Baylor - PlanoPlano, TX3.85Explore
123364Tulsa Spine & Specialty HospitalTulsa, OK3.81Explore
131287Parkview Ortho HospitalFort Wayne, IN3.79Explore
141317St Vincent Heart Center of IndianaIndianapolis, IN3.79Explore
151826Physicians Medical CenterHouma, LA3.75Explore
161100Northwest Specialty HospitalPost Falls, ID3.71Explore
17764511Baylor Scott & White the Heart Hospital Baylor - DentonDenton, TX3.69Explore
181818Avala Hospital (FKA Fairway Medical Center)Covington, LA3.68Explore
19975307Townsen Memorial HospitalHumble, TX3.6Explore
201090Treasure Valley HospitalBoise, ID3.6Explore
215692Fred Hutchinson Cancer Center (FKA Seattle Cancer Care Alliance)Seattle, WA3.56Explore
22329Fresno Surgical HospitalFresno, CA3.54Explore
232548CHI Health Nebraska Heart (FKA Nebraska Heart Hospital)Lincoln, NE3.43Explore
24552269Cypress Pointe Surgical HospitalHammond, LA3.41Explore
254095CHI St Luke's Health - Lakeside HospitalThe Woodlands, TX3.37Explore

Fig. 1. Data is from the Definitive Healthcare HospitalView product and sourced from the Medicare Cost Report. Accessed July 2023.

Which hospitals have the highest case mix index?

Nebraska Spine Hospital in Omaha and Doctors Hospital in Leawood, Kansas each have CMIs more than 5.25, the highest among U.S. hospitals. Both hospitals specialize in spine surgery, which can be a highly complex procedure and likely contributes to their CMIs.

What is the national average case mix index for hospitals?

Definitive Healthcare calculates a case mix index value for more than 5,800 hospitals in our HospitalView product. The average CMI is 1.50, with a range of values from 0.42 to 5.35.

CMI for the top 25 hospitals on the list above ranges from 3.37 to 5.35, with an average CMI of 3.95.

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