Assignment: Case Mix Index Analysis
Objectives:
1. Calculate the Case Mix Index for a selected group of cases.
2. Analyze Case Mix Indices for different facilities.
3. Evaluate the impact of utilization patterns on a facility's Case Mix.
Introduction
The case mix of a patient population is a description of that population based on any number of the following characteristics such as age, gender, treatments received or resources used. Case Mix Analysis is used to determine reimbursement, to describe a population being served and to identify differences in practice patterns or coding complexity.
The case mix index is the average of the relative weights of all cases treated at a given facility. The theoretical average CMI is 1.000. CMI's over 1.000 signify more complex cases and CMI's less than 1.000 signify less complex cases. Factors that influence a facility's case mix index include:
• Changes made in relative weight values
• Changes in the type of services offered or provided by the facility
• Accuracy of documentation and coding in MS-DRG or APC assignment
Case Mix Analysis begins with the calculation of the Case Mix Index. The Case-Mix Index is the average of the relative weights of all cases treated at a given facility or by a given physician. The formula for calculating the Case Mix Index is:
The total number of CMS Relative Weights for all of the cases divided by the total number of patients served.
The total CMS Relative Weight is 213.0332
The total number of patients served is 78
The Case Mix Index is 213.0332 / 78 = 2.7311
Part I Written Assignment
Scenario:
You are the HIM Director for PrimeCare Medical Center and you are charged with the task of analyzing your facility's case mix and comparing your Case Mix Index with comparable facilities in your area. The top 5 procedures performed in your facility are listed below:
PrimeCare - Top 5 MS DRGs
|
MS-DRG
|
Description
|
# of Pts.
|
CMS Relative Weight
|
|
037
|
Extra cranial Procedures w/MCC
|
35
|
3.0845
|
|
635
|
Major Bladder Procedures
|
29
|
5.9249
|
|
652
|
Kidney Transplant
|
27
|
3.0507
|
|
736
|
Uterine/ Adnexal Procedures for Malignancy w/MCC
|
25
|
4.5276
|
|
095
|
Bacterial/Tuberculosis Infections of the Nervous System w/CC
|
23
|
2.3762
|
a. Calculate the Case Mix Index for the top 5 MS DRGs for your facility. Report all calculations to four places after the decimal point for the most accurate CMI.
b. The Transplant Surgery Department has predicted a 20% increase in kidney cases for the next fiscal year and the Urology department has predicted a 10% decrease in major bladder procedures. Recalculate the CMI to account for these predictions. Report all calculations to four places behind the decimal point for the most accurate CMI.
c. Prepare a short report (1 pages) to the Finance Department that analyzes the impact of the projected changes in utilization practices. In your report include the new projected CMI. The purpose of the report would not be to give actual facts and figures just to identify areas that would be impacted by the projected changes.
Requirements
Table Complete and accurate
Impact on hospital finances evaluated and understanding of areas impacted by changes to table.
Prime Care-Top 5 MS DRGs
|
MS-DRG
|
Description
|
# of Pts.
|
CMS Relative Weight
|
Total CMS Relative Weight
|
|
037
|
Extracranial Procedures w/MCC
|
35
|
3.0845
|
107.9575
|
|
653
|
Major Bladder Procedures
|
26
|
5.9249
|
154.0474
|
|
652
|
Kidney Transplant
|
32
|
3.0507
|
97.6224
|
|
736
|
Uterine/Adnexal Procedures for Malignancy w/ MCC
|
25
|
4.5276
|
113.19
|
|
095
|
Bacterial/Tuberculosis Infections of the Nervous. System w/cc
|
23
|
2.3762
|
54.6526
|
|
|
Total
|
141
|
|
527.4699
|
To get the CMI divide the Total CMS Relative Weight by the number of patients.
527.4699/141= CMI of 3.7409