Last Updated: 2001-03-22
1. Case Mix:
Both are patient classification systems that provide ways of describing the types of patients a hospital treats (its case mix).
group cases into manageable number of meaningful patient categories
patients within each category are similar clinically and in terms of resource use
use administrative data to group cases
algorithm of DRG™/CMG™ assignments is identical except that CMGs™ were designed to be grouped according to the most responsible diagnosis
Diagnoses 01 to 25: mutually exclusive categories based on body systems.
within each category cases separated into medical and surgical.
then CMG™/DRG™ assigned.
Both CMGs™ and DRGs™ have weights associated with them that are supposed to reflect the relative costs for each group.
RIWs™: Resource Intensity Weights are the weights associated with CMGs™. They are based on charge data from Maryland and Canadian LOS
Available from CIHI with CMG™ grouper
DRG™ weights: weights associated with DRGs™ based on Medicare patients only; available from the USA
3. Complexity / Intensity of Refinement:
RDRGs® - for DRGs™
Complexity overlay - for CMGs™
These two refinements are very similar - CMGs™ also have age adjustment factor.
Weights available for complexity/intensity refinement:
RDRG® weights developed at MCHP for RDRGs®.
RIWs™ for complexity overlay.
Unlike DRGs™, CMGs™ may change number from one year to the next. This can create problems for longitudinal studies.
2. Complications and Comorbidities:
With CMG™ - they use diagnosis typing - can distinguish between a comorbidity (pre-existing additional diagnosis) and a complication (diagnosis that arose after admission). (DRG™ - comorbidities and complications are grouped together).
- Health Measures