Patients table

Patients table

Information that is consistent for the lifetime of a patient is stored in this table.

Table columns

Name Postgres data type
subject_id INTEGER
gender VARCHAR(1)
anchor_age INTEGER
anchor_year INTEGER
anchor_year_group VARCHAR(255)

Detailed Description


subject_id is a unique identifier which specifies an individual patient. Any rows associated with a single subject_id pertain to the same individual. As subject_id is the primary key for the table, it is unique for each row.


gender is the genotypical sex of the patient.

anchor_age, anchor_year, anchor_year_group

These columns provide information regarding the actual patient year for the patient admission, and the patient’s age at that time.

  • anchor_year is a shifted year for the patient.
  • anchor_year_group is a range of years - the patient’s anchor_year occurred during this range.
  • anchor_age is the patient’s age in the anchor_year. If a patient’s anchor_age is over 89 in the anchor_year then their anchor_age is set to 91, regardless of how old they actually were.
  • Example: a patient has an anchor_year of 2153, anchor_year_group of 2008 - 2010, and an anchor_age of 60.
    • The year 2153 for the patient corresponds to 2008, 2009, or 2010.
    • The patient was 60 in the shifted year of 2153, i.e. they were 60 in 2008, 2009, or 2010.
    • A patient admission in 2154 will occur in 2009-2011, an admission in 2155 will occur in 2010-2012, and so on.


The de-identified date of death for the patient. Date of death is extracted from the hospital information system only. Out-of-hospital mortality is currently unavailable as of MIMIC-IV v1.0.