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Central Distributor SID: Description of Data Elements

DaysBetweenVisits - Number of days between visits
Documentation Sections:
General Notes
Uniform Values
State Specific Notes
General Notes

Days between visits (DaysBetweenVisits) is retained as reported by data with two exceptions. Any source-specific value for "unknown" is recoded to missing (.), and invalid characters such as negative values are set to invalid (.A). No edit checks are performed on this data element during HCUP processing to verify the time between events.

Uniform Values
VariableDescriptionValueValue Description
DaysBetweenVisitsNumber of days between visits0 or higherDays between visits
State Specific Notes


Source documentation indicates that the days between visits is calculated by sorting the file by a unique patient identifier (that tracks individuals across hospitals), admission date, and discharge date. For patients with two or more admissions, the calculation subtracts the previous discharge date from the current admission date to find the days between visits.

In Massachusetts, a zero value for DaysBetweenVisits occurs in the following cases:.

  1. There is not a unique person identifier on the record (i.e., not reported, unknown or invalid).
  2. There is only one record for the patient in the calendar year.
  3. The discharge date on one admission is the same as the admission date on a subsequent admission. This situation occurs for transfer patients, as well as for women admitted into the hospital with false labor.


Starting in 2010, DaysBetweenVisits is no longer available.


Internet Citation: HCUP Central Distributor SID 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