The drgcodes table

Table source: Hospital database.

Table purpose: Contains diagnosis related groups (DRG) codes for patients.

Number of rows: 125,557

Links to:

• PATIENTS on SUBJECT_ID
• ADMISSIONS on HADM_ID

Important considerations

• HCFA-DRG and MS-DRG codes have multiple descriptions as they have changed over time. Sometimes these descriptions are similar, but sometimes they are completely different diagnoses. Users will need to select rows using both the code and the description.
• Since there are multiple versions of DRG codes, queries will need to incorporate both the type of DRG and the code when filtering for a certain diagnosis.
• All patients have an HCFA-DRG or MS-DRG code, but not all patients have an APR-DRG code. Note that APR-DRG is believed to be an alternative, more specific, code which could be used in conjunction with the HCFA codes.

Table columns

Name	PostgreSQL data type
ROW_ID	INT
SUBJECT_ID	INT
HADM_ID	INT
DRG_TYPE	VARCHAR(20)
DRG_CODE	VARCHAR(20)
DESCRIPTION	VARCHAR(300)
DRG_SEVERITY	SMALLINT
DRG_MORTALITY	SMALLINT

Detailed Description

SUBJECT_ID, HADM_ID

Identifiers which specify the patient: SUBJECT_ID is unique to a patient and HADM_ID is unique to a patient hospital stay.

DRG_TYPE

DRG_TYPE provides the type of DRG code in the entry. There are two types of DRG codes in the database which have overlapping ranges but distinct definitions for the codes. The three types of DRG codes in the MIMIC-III database are ‘HCFA’ (Health Care Financing Administration), ‘MS’ (Medicare), and ‘APR’ (All Payers Registry).

DRG_CODE

DRG_CODE contains a code which represents the diagnosis billed for by the hospital.

DESCRIPTION

DESCRIPTION provides a human understandable summary of the meaning of the given DRG code. The description field frequently has acronyms which represent comorbidity levels (comorbid conditions or “CC”). The following table provides a definition for some of these acronyms:

Acronym	Description
w CC/MCC	with CC or Major CC
w MCC	with Major CC
w CC	with CC and without Major CC
w NonCC	with NonCC and without CC or Major CC
w/o MCC	with CC or Non CC and without Major CC
w/o CC/MCC	with nonCC and without CC or Major CC

Note that there are three levels of comorbidities: none, with comorbid conditions, and with major comorbid conditions. These acronyms are primarily used in HCFA/MS DRG codes.

DRG_SEVERITY, DRG_MORTALITY

DRG_SEVERITY and DRG_MORTALITY provide additional granularity to DRG codes in the ‘APR’ DRG type. Severity and mortality allow for higher billing costs when a diagnosis is more severe, and vice versa.