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Central Distributor SASD: Description of Data Elements

DOB - Date of birth
Documentation Sections:
General Notes
Uniform Values
State Specific Notes
General Notes

DOB is assigned a valid nonmissing birthdate, with the following exceptions:

  • If a date of birth is supplied by the data source, but one or more of the components of the birthdate (year, month, day) is
    • Blank or a documented missing value, then DOB = missing (.).
    • - or -
    • Nonnumeric or out of range (year NE 00-99, month NE 1-12, day NE 1-31), then DOB = invalid (.A).
  • If the day of birth is inconsistent with the month (e.g., February 30), then DOB = invalid (.A).
  • If the data source does not provide the date of birth, then beginning in the 1998 data, DOB is not present on the HCUP files. In the 1988-1997 data, DOB is retained on the HCUP files and is set to unavailable from source (.B).
  • If the birthdate is confirmed to be a valid date, but the calculated age is negative:
    • Beginning in the 1998 data, DOB and AGE are set to inconsistent (.C) by edit check EAGE02. AGEDAY and AGEMONTH are set to missing (.).
    • From 1988-1997 data, DOB remains unchanged, and AGE and AGEDAY are set to invalid (.A). AGEMONTH is not available on the 1988-1997 HCUP databases.

To ensure the confidentiality of patients on the HCUP Central Distributor files, full dates are not released. Beginning in the 1998 data, DOB is replaced by birth month (BMONTH) and birth year (BYEAR). In databases before 1998, the day portion of the date stored in DOB is overwritten with "01" during the creation of the Distributor files. The month and year portion of the date remains unchanged. HCUP data elements that are calculated from DOB are computed before DOB is masked.

Uniform Values
VariableDescriptionValueValue Description
DOBDate of birthYYYYMMDDDate of Birth
.BUnavailable from source (coded in 1988-1997 data only)
.CInconsistent: beginning with 1998 data, EAGE02
State Specific Notes

New York

Beginning with the 2008 data,the HCUP data element DOB is missing (.) for AIDS/HIV patients. New York identifies AIDS/HIV records by ICD-9-CM diagnosis code, DRG, or MS-DRG:

  • An admitting, principal or any secondary diagnosis of "042", "043", "044", "7958", "27910", "27919", "2793", "1363", "79571", "07951", "07952", "07953", "V017" or "V08".
  • A DRG of 488 through 490 (prior to October 2007) or MS-DRG of 700 through 716 (beginning in October 2007).

Please note that the admitting diagnosis is not retained in the HCUP databases prior to 2012.

In the 1988-1997 HCUP New York databases, the data source provided birth year and month, but did not provide the day. A day of "01" was imputed for all records. The imputed date was not used to calculate other data elements or to perform edit checks. Beginning in 1998, the complete date of birth was provided by the data source.


Internet Citation: HCUP Central Distributor SASD Description of Data Elements - All States. Healthcare Cost and Utilization Project (HCUP). May 2024. Agency for Healthcare Research and Quality, Rockville, MD.
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Last modified 5/22/24