DRG

Diagnosis-related group (DRG) is a patient classification system that standardizes prospective payment to hospitals and encourages cost containment initiatives. In general, a DRG payment covers all charges associated with an inpatient stay from the time of admission to discharge.

MS-DRG

A Medicare Severity-Diagnosis Related Group is a classification system (referred to as DRG) for inpatient discharges, which adjusts payments under the Inpatient Prospective Payment System (IPPS) based on appropriate weighting factors assigned to each DRG. In OMOP CDM, MS-DRG is represented as a separate concept class from DRG.

Sources

The vocabulary is retrieved from the Centers for Medicare and Medicaid Services (CMS) Website.

Transformation

The procedures for transforming Concepts from the source to the OMOP Standard Vocabularies can be found on the OHDSI GitHub.

Concept Names

All Concepts are assigned the longest of all available names.

Concept Code

Concept Codes are 3-digit DRG codes.

Standard Concepts

MS-DRG codes are mostly standard.

Domains

All DRG concepts are of the Observation domain.

Domain	Notes
Observation

Concept Classes

Class	Notes
DRG
MS-DRG

ETL process

1. If event_date < = 2007-09-30 source DRG codes should be mapped to source_vocabulary_id = 'DRG' and source concept_class_id = 'DRG'
2. If event_date > = 2007-10-01 source DRG codes should be mapped to source vocabulary_id = 'DRG' and source concept_class_id = 'MS-DRG'

Note: MS-DRG codes of '156', '155', '251','154', '250' should be filtered using invalid_reason is null due to the intersection of valid dates.