The HCUP Supplemental Variables for revisit analyses are designed to facilitate analyses that need to track patients across time and hospital settings in the SID, SASD, and SEDD while adhering to strict privacy guidelines. They are part of a family of databases and software tools developed as part of the Healthcare Cost and Utilization Project (HCUP) a Federal-State-Industry partnership sponsored by the Agency for Healthcare Research and Quality. HCUP databases, tools, and software inform decision making at the national, State, and community levels.

Contents:

• Overview
• How Can the HCUP Variables for Revisit Analyses be Used?
• For Which States and Data Years are Revisit Variables Available?
• Hardware and Software Requirements
• User Guides
• How Can Users Obtain the HCUP Supplemental Variables for Revisit Analyses?

The HCUP State databases are often characterized as being discharge-level files, meaning that each record in a database represents one discharge abstract from a hospital setting, which can be an inpatient, emergency department or ambulatory surgery visit. Thus, if the same individual visited the hospital three times in a given year, the HCUP databases would include three separate records in the respective HCUP database. Many times researchers may be interested in knowing how many visits a distinct patient had rather than simply the number of overall hospital visits. In order to track an individual patient over time, it is necessary to have a unique identifier for an individual that remains consistent across different facilities and hospital settings in a state.

The HCUP variables for revisit analyses can be used to track sequential visits for a patient within a state and across facilities and hospital settings (inpatient, emergency department, ambulatory surgery) while adhering to strict privacy guidelines. There are two HCUP supplemental variables:

• Synthetic person-level identifiers that have been verified against the patient's date of birth and gender and examined for completeness (HCUP variable VisitLink).
• A timing variable that can be used to determine the days between hospital events for an individual without the use of actual dates (admission, discharge or birth) (HCUP variable DaysToEvent).

The HCUP revisit variables are designed to be used exclusively with the HCUP SID, SASD, and SEDD. The storage of these variables varies by data year.

• Starting in 2009, the revisit variables are stored in the Core file of the SID, SASD, or SEDD.
• For data years 2003-2008, the revisit variables are stored in separate supplemental files. These files are unique within state and data year. Users will need to merge the revisit variables to the corresponding SID, SASD, or SEDD for any analysis by KEY.

The HCUP revisit variables can be used to track sequential visits for a patient within a state and across facilities and hospital settings (inpatient, emergency department, and ambulatory surgery) while adhering to strict privacy guidelines.

The revisit variables allow HCUP researchers to uniformly identify sequential visits for an individual, and then use the available clinical information to determine if the visits are unrelated, expected follow-up, complications from a previous treatment, or an unexpected revisit or rehospitalization. Total charge information from each visit can be combined to determine a total charge or cost for an episode of hospital care. Many types of studies are now possible. A few possible analyses include:

• Repeat ED use
• Readmissions to the hospital
• Admissions to the hospital after ambulatory surgery
• Patterns of ED and hospital utilization for chronic conditions.

The HCUP revisit variables are available for the SID, SASD, and SEDD in select States starting in 2003. Appendix A of the User Guide provides a detailed list of which States, years, and types of data are available.

The HCUP revisit variables must be used with the HCUP SID, SASD, or SEDD. The 2003-2008 Supplemental Revisit Files are available in ASCII format. The SID, SASD, and SEDD files require a statistical software package such as SAS or SPSS to use for analytic purposes.

The User Guide for the HCUP revisit variables contains:

• A more detailed description of the files and data elements
• Instructions for linking the revisit variables to the SID, SASD, or SEDD (for 2003-2008)
• Considerations for any revisit analysis
• Usage examples.

• User Guide: HCUP Supplemental Variables for Revisit Analyses (PDF file, 444 KB)
  • Appendix Tables (Excel file, 153 KB)

Beginning with the 2009 data, the revisit variables are included in the Core file of the SID, SASD, and SEDD files available for purchase through the HCUP Central Distributor, when possible. For 2003-2008 data, the HCUP Supplemental Files for Revisit Analyses are provided as a separate file included when purchasing the SID, SASD, and SEDD from the HCUP Central Distributor SID, SASD, and SEDD.