Top 25 hospitals by case mix index 

Case Mix Index (CMI) reflects the complexity of a hospital’s patient population and the associated resources for their care. Patients are classified into Medicare severity diagnosis-related groups (MS-DRGs) depending on condition, case complexity and medical needs. CMI is the average of MS-DRG weights compared to the total number of discharges in a given time period.

How does case mix index affect reimbursement?

The Centers for Medicare and Medicaid Services (CMS) uses CMI to determine reimbursement for Medicare and Medicaid beneficiaries. CMS evaluates the resources required to treat patients in each DRG compared to other DRGs and to patients outside a DRG. Higher CMI often results in higher reimbursement rates.

What is the primary use of case mix index?

Case mix helps healthcare leaders understand their patient populations, review procedure volumes, budget reimbursement expectations and adjust expenses. It is used to calculate the average care cost per hospital patient. For example, if a hospital’s average cost per patient is $1,000 and its annual CMI is 0.80, the adjusted cost per patient would be $1,250. As an indicator of hospital performance, CMI is also used to compare individual hospitals.

What is the average hospital case mix index?

Definitive Healthcare records the CMI for over 5,900 hospitals in our HospitalView product. The average CMI is 1.48 with a range of values from 0.25 to 5.69. The following table lists the top 25 hospitals with the largest case mix index.

Top 25 hospitals with highest case mix index

Rank Definitive ID Hospital Name Case Mix Index Net Patient Revenue # of Discharges
1 1561 Doctors Hospital LLC 5.69 $31,659,770 240
2 2148 Children's Hospitals and Clinics of Minnesota - Minneapolis 5.60 $740,172,074 11,114
3 552489 Nebraska Spine Hospital 5.24 $48,914,298 799
4 4164 Northwest Hills Surgical Hospital 4.51 $26,312,438 466
5 3321 Oklahoma Spine Hospital 4.42 $66,829,360 1,641
6 1756 The Spine Hospital of Louisiana at the NeuroMedical Center 3.89 $48,983,837 1,230
7 1317 St Vincent Heart Center of Indiana 3.84 $193,855,357 3,935
8 3364 Tulsa Spine & Specialty Hospital 3.83 $67,900,516 902
9 2548 CHI Health Nebraska Heart 3.76 $64,031,283 2,054
10 975307 Townsen Memorial Hospital 3.68 $16,349,242 120
11 3901 Baylor Scott & White the Heart Hospital Baylor - Plano 3.64 $382,415,993 5,456
12 3744 Saint Thomas Hospital for Specialty Surgery 3.57 $68,209,648 1,363
13 1100 Northwest Specialty Hospital 3.37 $76,709,411 1,040
14 5692 Seattle Cancer Care Alliance 3.36 $890,271,266 581
15 1287 Parkview Ortho Hospital 3.33 $176,112,800 1,316
16 3716 Dunes Surgical Hospital  3.32 $94,693,851 914
17 1826 Physicians Medical Center 3.32 $17,167,293 319
18 1818 Avala Hospital 3.31 $50,230,671 821
19 552269 Cypress Pointe Hospital 3.28 $26,813,690 569
20 5199 Children's Wisconsin 3.27 $641,844,602 7,528
21 1090 Treasure Valley Hospital 3.25 $95,673,428 587
22 440 Keck Hospital of USC 3.24 $1,130,432,559 10,433
23 1738 Specialists Hospital Shreveport 3.24 $55,589,371 922
24 764511 The Heart Hospital Baylor - Denton 3.24 $56,608,551 695
25 6419 Akron Children's Hospital 3.23 $853,395,279 8,142

Fig. 1 Data is from the Definitive Healthcare HospitalView product. Data is sourced from the Medicare Cost Report. The most recent data is from the January 2022 release and new data is released quarterly. Accessed March 2022.

CMI for the top 25 hospitals range from 3.23 to 5.69 with an average CMI of 3.78. There was a slight increase from the average CMI of 3.48 for the top hospitals in 2018. With patients delaying care during the COVID-19 pandemic, hospitals were seeing the most severe patients, potentially increasing CMIs.

Doctors Hospital LLC in Leawood, Kansas has the highest CMI at 5.69. The hospital has specialized services and less than 300 discharges, factors likely contributing to their CMI. Children’s Hospitals and Clinics of Minnesota – Minneapolis has the second highest CMI at 5.60.

Since CMI is a reflection of the type of care a patient receives, the complexity of their cases and cost of care, it is no surprise to see specialized hospitals on this list. In addition to three children’s hospitals, the list also includes spine (4), heart (3) and surgical hospitals (3).

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