Case mix

The term Casemix refers to the type or mix of patients treated by a hospital or unit. The term is often used to describe the billing system of the hospital or unit, since the "cost per item" of healthcare is based on the casemix.

Background
Casemix based funding is the key funding model currently used in Australian health care services for reimbursement of the cost of patient care.

In the Netherlands, the casemix system is called a "DBC" (Dutch:Diagnosebehandelcombinatie), and can be defined as a predefined average care package, which is applied with a fixed price when a specific diagnosis occurs.

Casemix is a system that measures hospital performance, aiming to reward initiatives that increase efficiency in hospitals. It also serves as an information tool that allows policy makers understand the nature and complexity of health care delivery.

Diagnosis Related Groups (DRGs) is the best-known classification system that is used in this funding model. It classifies acute inpatient episodes into a number of manageable categories based on clinical condition and resource consumption. A single acute episode of inpatient care is allocated to one DRG using coded clinical information derived from the patient’s medical record. This information is coded by the Health Information Managers in order to allocate a DRG. Each DRG is allocated a ‘weight’, which is dependent on the average cost of inputs (e.g. nursing, diagnostic services, procedures) required to achieve the appropriate patient outcome. The facility is reimbursed a predetermined amount for each patient episode.

Classification systems
The casemix system introduces a kind of Activity Based Costing to the health profession. However the complexities of the system (in the Netherlands, over 100,000 DBC's can be theoretically charged) has led new initiatives to link billable activities directly to international standards, such as the ICD-10. This will eventually allow the billing processes to become more aligned in their classification schemes with the electronic patient record.

Casemix systems for mental health
Because mental health treatment does not lend itself to fixed price costing, other exceptions are made by insurance companies for payment in the case of longer term casemix averages.