The patients table

Table source: CareVue and Metavision ICU databases.

Table purpose: Defines each SUBJECT_ID in the database, i.e. defines a single patient.

Number of rows: 46,520

Links to:

• ADMISSIONS on SUBJECT_ID
• ICUSTAYS on SUBJECT_ID

Important considerations

• DOB has been shifted for patients older than 89. The median age for the patients whose date of birth was shifted is 91.4.

Table columns

Name	Postgres data type
ROW_ID	INT
SUBJECT_ID	INT
GENDER	VARCHAR(5)
DOB	TIMESTAMP(0)
DOD	TIMESTAMP(0)
DOD_HOSP	TIMESTAMP(0)
DOD_SSN	TIMESTAMP(0)
EXPIRE_FLAG	VARCHAR(5)

Detailed Description

SUBJECT_ID

SUBJECT_ID is a unique identifier which specifies an individual patient. SUBJECT_ID is a candidate key for the table, so is unique for each row. Information that is consistent for the lifetime of a patient is stored in this table.

GENDER

GENDER is the genotypical sex of the patient.

DOB

DOB is the date of birth of the given patient. Patients who are older than 89 years old at any time in the database have had their date of birth shifted to obscure their age and comply with HIPAA. The shift process was as follows: the patient’s age at their first admission was determined. The date of birth was then set to exactly 300 years before their first admission.

DOD, DOD_HOSP, DOD_SSN

DOD is the date of death for the given patient. DOD_HOSP is the date of death as recorded in the hospital database. DOD_SSN is the date of death from the social security database. Note that DOD merged together DOD_HOSP and DOD_SSN, giving priority to DOD_HOSP if both were recorded.

EXPIRE_FLAG

EXPIRE_FLAG is a binary flag which indicates whether the patient died, i.e. whether DOD is null or not. These deaths include both deaths within the hospital (DOD_HOSP) and deaths identified by matching the patient to the social security master death index (DOD_SSN).