Add Diagnosis-Related Group (DRG) to COST

[clairblacketer]

Add Diagnosis-Related Group (DRG) to COST

• Requester: OMOP-PCORnet Interoperability Collaborative (c/o Rimma Belenkaya)

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Proposal

Relevant table: COST

Background

This proposal applies only to US Diagnosis-Related Groups (DRGs). DRG is a system to
classify hospital cases into one of approximately 500 groups. They have been used in the
United States since 1983. There is more than one DRG system being used in the United States,
but only the MS-DRG (Medicare Severity Diagnosis Related Grouper) system is used by
Medicare. OMOP vocabulary includes MS-DRG version 33.0 released in October 2015, the
vocabulary_id is ‘DRG’.
Presently, US DRG code is stored in the Observation table and linked to Visit_Occurrence table
via visit_occurrence_id.

Proposed Change

Move DRG from Observation to the new Cost table as a first class attribute. Link it to
Visit_Occurrence table via visit_occurrence_id.
Add the following DRG fields to Cost table:

Field	Required	Type	Description
DRG_CONCEPT_ID	Integer	No	A foreign key to the predefined concept in the DRG Vocabulary reflecting the DRG for a visit.
DRG_SOURCE_VALUE	Varchar(3)	No	The 3-digit DRG source code as it appears in the source data.

Conventions

Multiple DRG Codes

Occasionally, one visit may have multiple DRG codes. In this case, there will be multiple
costs associated with these DRG codes. In OMOP CDM, they will be represented by
multiple records containing corresponding costs and DRG codes in the Cost table.

Vocabulary Mapping

Source codes coming from DRG systems other than MS-DRG should be mapped to
concept_id = 0.

Use Cases

DRG codes are used in the analysis of cost-efficiency and designs of a hospital payment system. The Affordable Care Act and other recent legislation affect medical reimbursement by altering the DRG system. This legislation will give DRGs an even larger role in determining reimbursements in the coming years.

Consequences

• This change is an important enhancement to the model and can be implemented immediately
  without impacting other projects.
• It will have an immediate effect on the three OMOP-based CDRNs: NYC-CDRN representing
  over 2.5 million patients; pSCANNER covering over 21 million patients; and PEDSnet which
  includes eight of the nation's largest children's hospitals and provides service to 4.6 million
  children per year.
• This change will enhance representation and analysis of DRG codes in OMOP CDM and
  simplify ETL for the sites that are presently using Observation table.
• It will have no implications on vocabulary or existing software.

References

1. Weiland DE, ea. Using Delta/DRG Diagrams and Decision Tree Analysis to Select a
   Cost-Effective Surgery for Cholecystitis. JSLS. 1997 Apr-Jun.
2. Vertrees JC , ea. Bundling post-acute care services into MS-DRG payments.Medicare
   Medicaid Res Rev. 2013 Aug 2.
3. Rimler SB , ea. Radiographics. Diagnosis-related Groups and Hospital Inpatient Federal
   Reimbursement. 2015 Oct.

[clairblacketer]

Closing this issue as it was added to CDM v5.2