The State Ambulatory Surgery and Services Databases (SASD) are part of the family of databases and software tools developed for the Healthcare Cost and Utilization Project (HCUP). The SASD include encounter-level data for ambulatory surgeries and may also include various types of outpatient services such as observation stays, lithotripsy, radiation therapy, imaging, chemotherapy, and labor and delivery. The specific types of ambulatory surgery and outpatient services included in each SASD vary by State and data year. All SASD include data from hospital-owned ambulatory surgery facilities. In addition, some States include data from nonhospital-owned facilities.

Developed through a Federal-State-Industry partnership sponsored by the Agency for Healthcare Research and Quality, HCUP data inform decision making at the national, State, and community levels.

This page provides an overview of the SASD. For more details, see SASD Database Documentation and the Introduction to the SASD (PDF file, 465 KB; HTML).

Contents:

• About the SASD
• SASD Data Elements
• SASD File Structure
• SASD Areas of Research and HCUP Publications
• Purchase the SASD
• SASD Hardware and Software Requirements

The SASD include encounter-level data for ambulatory surgery and other outpatient services from hospital-owned facilities. In addition, some States provide ambulatory surgery and outpatient services from nonhospital-owned facilities. The specific types of ambulatory surgery and outpatient services included in each SASD vary by State and data year. A number of States make their SASD files available for purchase through the HCUP Central Distributor. See Availability of HCUP Data for a list of State database participation and availability by year.

Thirty-five States now participate in the SASD:

• The SASD include encounter-level data for ambulatory surgery and other outpatient services from hospital-owned facilities in participating States that are translated into a uniform format to facilitate multistate comparisons and analyses.
• All SASD include data from hospital-owned ambulatory surgery facilities. In addition, some States include data from facilities not owned by a hospital.
• The databases contain a core set of clinical and nonclinical information on all patients, regardless of payer, including those covered by Medicare, Medicaid, private insurance, and the uninsured.
• In addition to the core set of uniform data elements common to all SASD, some include other elements such as the patient's race.

Free HCUP Tools & Software are also available to identify preventable hospitalizations, estimate costs, assess quality of care and patient safety, categorize diagnoses and procedures, and identify comorbidities.

Additional information on the SASD may be found in the Introduction to the SASD (PDF file, 465 KB; HTML).

The SASD contain clinical and resource-use information that is included in a typical discharge abstract, with safeguards to protect the privacy of individual patients, physicians, and hospitals (as required by data sources). The SASD contain more than 100 clinical and nonclinical variables included in a hospital discharge abstract, such as:

• All-listed diagnoses and procedures
• Patient demographic characteristics (e.g., sex, age, and, for some States, race)
• Expected payment source
• Total charges
• Hospital identifiers that permit linkage to inpatient hospital databases, such as the AHRQ-sponsored State Inpatient Databases (SID) and the American Hospital Association Annual Survey File

Elements included in the SASD are not always available for all States, including the hospital county identifiers or HCUP's Revisit Variables. Please see the Availability of Data Elements by Year.

The SASD are calendar year files based on discharge date for all data years except 2015. Because of the transition to ICD-10-CM/PCS on October 1, 2015, the 2015 SASD are split into two parts. Nine months of the 2015 data with ICD-9-CM codes (discharges from Jan 1, 2015 - September 30, 2015) are in one set of files labeled Q1Q3. Three months of 2015 data with ICD-10-CM/PCS codes (discharges from October 1, 2015 - December 31, 2015) are in a separate set of files labeled Q4. More information about the changes to the HCUP databases for ICD-10-CM/PCS and use of data across the two coding system may be found on the HCUP-US website under ICD-10-CM/PCS Resources.

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The SASD are well suited for research that requires complete enumeration of ambulatory surgery in hospital-owned facilities within market areas or States. Used with the SID, the SASD may be used to compare inpatient surgery data with ambulatory surgery data. The SASD promote comparative studies of healthcare services and support healthcare policy research on a variety of topics, including:

• Analyses of ambulatory surgeries
• Trends in ambulatory surgery utilization, access, charges, and outcomes
• Shift in surgical procedures to outpatient facilities
• Diffusion of medical technology

The SASD are used in a variety of publications:

• HCUP Statistical Briefs highlight a variety of health topics.
• Use the HCUP Publications Search Tool to find publications using the SASD.
• Review featured publications on the HCUP Research Spotlights page.
• Read publications by the winners of the HCUP Outstanding Article of the Year Awards.

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SASD releases beginning in data year 1997 are available for purchase through the HCUP Central Distributor. Costs vary by State and data year.

All HCUP data users, including data purchasers and collaborators, must complete the online HCUP Data Use Agreement Training Tool, and must read and sign the Data Use Agreement for State Databases (PDF file, 251 KB; HTML).

The SASD are available for purchase online through the HCUP Central Distributor.

Questions regarding purchasing databases can be directed to the HCUP Central Distributor:

E-mail: HCUP@AHRQ.gov
Telephone: (866) 290-4287 (toll free)

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The SASD data set comes in ASCII format and can be run on desktop computers with a DVD drive. To load and analyze the SASD, you will need the following:

• A DVD drive
• A hard drive with one to four gigabytes of space available, depending on the SID being used
• SAS®, SPSS®, or similar analysis software

The data set comes with full documentation. SASD documentation and tools, including programs for loading the ASCII file into SAS or SPSS, are also available on the SASD Database Documentation page.

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