Case Mix Management

CMI usage and calculations

By: Deborah Balentine M.Ed, RHIA, CCS-P

What is a Case-Mix? Age Gender Type of Insurance Diagnosis Risk Factors Treatments received Resources used

Purposes To determine reimbursement.

DRGs APCS MPFS

To describe a population being served.

To identify differences in practice patterns or coding complexity.

Severity of Illness Classifications Extent of the disease Risk of mortality Need for intervention Urgency of care Intensity of resources Difficulty of treatment

Severity of Illness Classfications Adjusted Clinical Groups National Association of Children’s

Hospital and Related Institutions (NACHRI)

Medical Outcomes Study Short Form Health Survey

Atlas System

Diagnostic/Procedural/Severity Classifications Resource Utilization Groups (RUGs)

Functional Related Group System (IRFPPS)

Home Health Resource Grouping System (HHPPS)

Risk Adjustment Age and gender adjustments Clinical risk adjustments Situation-specific adjustments Adjustments for specific clinical

conditions Adjustments by specialty type

Case-Mix Index Classification by Disease Conditions

and/or Procedures Determines patterns of resource use Used to determine anticipated

reimbursement. Comparison to other facilities

Factors that influence Case-Mix Changes in Relative Weights Changes in Services Accuracy in Documentation and

Coding Accuracy in DRG/APC assignment

Calculating Case-Mix Indexes Calculating Total CMS Relative Weight Calculating Case Mix Index Calculating Medicare Payment Determining the Highest Relative

Weight

Calculating Case-Mix Index Services to be measured Relative Weight # of Cases

Case Mix Formulas Calculating Total CMS Relative

Weights Calculating Medicare/Third-Party

Payment Calculating Case-Mix Index Determining the Highest Relative

Weight for a group of cases

Calculating Total CMS Relative Weight

Multiply the “CMS Relative Weight” by the total number of cases (patients) in the DRG group

Example One

A facility has 29 Medicare cases that are assigned to DRG 69 which has a relative weight of 1.0005. What is the Total Relative Weight for the cases?

Answer29.0145

1.0005 x 29

Example Two

A facility has 15 Medicare cases that are assigned to DRG 117 which has a relative weight of 0.7789. What is the Total Relative Weight for all of the cases?

Answer11.6835

0.7789 x 15

Calculating Medicare Payment

Multiply the reimbursement per case by the number of cases performed

Example Three

A facility has 22 Medicare cases which are reimbursed at $6,175 per case.

What is the total Medicarereimbursement for all of the cases?

Answer

$135,850.00

$6,175 x 22

Example FourA facility has 59 Medicare cases that are

assigned to DRG 175 which has a relative weight of 0.9557.

If the hospital PPS rate is $4,200, what is the total reimbursement for all of the cases?

Answer$236,822.46Step One: Calculate the reimbursement

per case0.9557 x $4,200 (PPS rate) = $4,013.94Step Two: Multiply by the number of

cases$4,013.94 x 59 = $236,822.46

Calculating Case Mix Index

The total number of CMS Relative Weights divided by the total number of patients served.

Example FiveThe top ten DRG surgical procedures

performed by a facility have a total CMS Relative Weight of 45.8775.

If the total number of patients served is 29, what is the Case-Mix Index for the facility?

Answer

1.5819

44.8775 / 29 = 1.5819

Example SixThe top ten DRG medical procedures

performed by a facility have a total CMS Relative Weight of 23.6651

If the number of patients served is 55, what is the Case-Mix Index for the facility?

Answer

0.4302

23.6651 / 55 = 0.43027 or 0.43028

Recap The case mix of a patient population is a

description of that population based on any number of characteristics.

Case-Mix indexes are used to describe a population that is being served, to determine reimbursement, and to identify differences in practice patterns or coding complexity.

The most commonly used Case-Mix Index uses disease conditions and/or procedures to determine resource use.

Recap (cont.) Severity of Illness case-mix methodologies

were developed to address concerns that traditional case-mix methodologies do not capture the severity of an illness.

Risk Adjustment is any method used to compare the severity of illness in one group of patients in comparison to the severity of illness in another group of patients. Used make a fair comparison of diverse populations and treatment patterns