On a semi-annual basis (every six months), hospitals submit abstracted information from individual patient records which include data on the patient’s zip code, gender, birthdate, and preferred language; status at admission; diagnoses, treatments/procedures, total charges, and expected source of payment. To protect individual patient confidentiality, data are aggregated into data products which are available on an annual basis.

Available Data Products

  1. Case Mix Index
  2. County Frequencies
  3. ICD-9/ICD-10-CM Code Frequencies – Diagnosis Codes
  4. ICD-9/ICD-10-CM Code Frequencies – External Cause of Injury/Morbidity Codes
  5. ICD-9/ICD-10-CM Code Frequencies – Procedure Codes
  6. Individual Hospital Top 25 MS-DRG Pivot Profile
  7. Patient Origin/Market Share Pivot Table
  8. Pivot Profile
  9. Statewide Benchmark Top 25 MS-DRG Pivot Profile

Case Mix Index

The Case Mix Index (CMI) is a measure of the relative cost or resources needed to treat the mix of patients in each licensed California hospital during the calendar year.

To calculate the CMI, OSHPD uses Medicare Severity-Diagnosis Related Groups (MS-DRG) and their associated weights, assigned to each MS-DRG by the Centers for Medicare & Medicaid Services (CMS). Each patient record is assigned an MS-DRG based on the principal and secondary diagnoses, age, procedures performed, the presence of co-morbidities and/or complications, discharge status, and gender. Each MS-DRG has a numeric weight reflecting the national “average hospital resource consumption” by patient for that MS-DRG, relative to the national “average hospital resource consumption” of all patients. Although the MS-DRG weights are based on resource consumption by Medicare patients, OSHPD applies them to all patient discharge data reported by hospitals in California during the course of a calendar year.

Example: How the CMI is used and the method to calculate it

On October 1, 2007 CMS replaced the then-current 538 DRGs with 745 MS-DRGs. OSHPD implemented these changes with the release of its 2008 Patient Discharge Data. The grouper software is updated by CMS at the beginning of each federal fiscal year (October 1st) and applied to patient records based on their reported discharge date. In the past, OSHPD adjusted the grouper and applied it to records based on a calendar year. With the implementation of MS-DRG, OSHPD now applies the grouper to patient records based on the federal fiscal year. MS-DRG Grouper version 25.0 was applied to discharges from January 1, 2008 through September 30, 2008. MS-DRG Grouper version 26.0 was applied to the discharges from October 1, 2008 through September 30, 2009 and so on for subsequent years. Because of this change, the CMI for each hospital is based on patient discharges within a given federal fiscal year beginning on October 1, 2008 and forward.

County Frequencies

These frequency tables display discharge totals  by county for a selected group of data elements.  Data elements represented in these tables include: Medicare Severity-Diagnosis Related Group (MS-DRG), Gender, Race, Expected Source of Payment, Source of Admission, Type of Care, and Disposition.

ICD-9/ICD-10-CM Code Frequencies – Diagnosis Codes

The statewide counts of each Diagnosis Code is displayed as Total, Principal, and Secondary Codes.

ICD-9/ICD-10-CM Code Frequencies – External Cause of Injury/Morbidity Codes

The statewide counts of each External Cause of Injury/Morbidity Code is displayed as Total, Principal, and Secondary Codes.

ICD-9/ICD-10-CM Code Frequencies – Procedure Codes

The statewide counts of each Procedure Code is displayed as Total, Principal, and Secondary Codes.

Individual Hospital Top 25 MS-DRG Pivot Profile

The Excel Pivot Profiles were developed using the patient discharge data file aggregated at the hospital level. The files display the total number of discharges, average charge per stay, average charge per day and average length of stay for the top 25 Medicare-Severity Diagnosis Related Groups (MS-DRGs) for each hospital and for the state as a whole. 

On October 1, 2007 the Centers for Medicare & Medicaid Services (CMS) replaced the current 538 Diagnosis Related Groups (DRGs) with 745 MS-DRGs. The grouper software is updated by CMS at the beginning of each federal fiscal year (October 1st); because of this change the Top 25 MS-DRG reports are based on discharges from October 1st of one year through September 30th of the following year.

Patient Origin/Market Share Pivot Table

This product contains the Patient Origin and Market Share Pivot Tables. These pivot tables identify where in the state (specified by ZIP Code) patients come from for treatment at a selected hospital, as well as the hospitals that patients from a selected ZIP Code or county go to for treatment.

Pivot Profile

The annual Excel pivot tables display summaries of the inpatients treated in each hospital. The summary data include discharges, discharge days, average length of stay, age groups, race groups, sex, expected payer, type of care, do not resuscitate orders, admission source, admission type, discharge disposition, principal diagnosis groups, principal procedure groups, and principal external cause of injury/morbidity groups. The data can also be summarized statewide or for a specific hospital county, bed size grouping, and/or type of control.

Statewide Benchmark Top 25 MS-DRG Pivot Profile

The Excel Pivot Profiles meet the requirements established by AB 1045 and were developed using the patient discharge data file aggregated at the hospital level. Using the statewide Top 25 Medicare Severity Diagnosis Related Groups (MS-DRGs) as benchmarks, the table displays the total number of discharges, average charge per stay for the selected hospital, average charge per stay statewide, and compares the hospital and statewide charges. Note that any particular hospital may not have discharges in all 25 of the diagnosis related groups (e.g., specialty hospitals such as maternity hospitals will not have MS-DRGs for cardiac surgery).

On October 1, 2007 the Centers for Medicare & Medicaid Services (CMS) replaced the current 538 diagnosis-related groups (DRGs) with 745 MS-DRGs. OSHPD implemented these changes with the release of its 2008 Patient Discharge Data. The grouper software is updated by CMS at the beginning of each federal fiscal year (October 1st); the top Benchmark MS-DRG reports are based on discharges from October 1st of one year through September 30th of the following year.