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AHCPR makes uniform State hospital data more accessible to researchers

The State Inpatient Databases (SID), created by the Agency for Health Care Policy and Research's Healthcare Cost and Utilization Project, are a powerful set of hospital databases from data organizations in 22 participating States. Researchers and policymakers use the SID to identify State-specific trends in inpatient care utilization, access, charges, and outcomes; investigate questions unique to one State; compare data from two or more States; and conduct market area research or small area variation analyses.

  • Each SID database contains the universe of the inpatient discharge abstracts in that State, translated into a uniform format to facilitate multi-State analyses.
  • Together, the SID contain data on more than half of all U.S. community hospital discharges. Some States include discharges from specialty facilities such as psychiatric hospitals.
  • The SID contain a core set of clinical and nonclinical information on all patients, regardless of payer, including people covered by Medicare, Medicaid, private insurance, and the uninsured.
  • In addition to the core set of uniform data elements common to all SID, some of the databases are enhanced to include other elements, such as the patient's race.

The 22 States participating in SID are:

Arizona, California*, Colorado*, Connecticut, Florida, Georgia, Hawaii, Illinois, Iowa, Kansas, Maryland, Massachusetts*, Missouri, New Jersey*, New York*, Oregon*, Pennsylvania, South Carolina*, Tennessee, Utah, Washington*, and Wisconsin*.

*States with an asterisk have SID files available through a central distributor as of September 1999.

What's in the SID?

More than 100 clinical and nonclinical variables that are part of a hospital discharge abstract. These include:

  • Principal and secondary diagnoses.
  • Principal and secondary procedures.
  • Admission and discharge status.
  • Patient demographics (e.g., sex, age, and, for some States, race).
  • Expected payment source (e.g., Medicare, Medicaid, private insurance, self-pay; and for some States, additional discrete categories such as managed care).
  • Total charges.
  • Length of stay.
  • For some States, hospital and county identifiers that permit linkage to the American Hospital Association Annual Survey files and the Area Resource File.

The SID can be run on desktop computers with a CD-ROM reader. The SID come with full documentation in ASCII format for ease of use with various off-the-shelf software products, including SAS and SPSS. SAS users are provided programs for converting the ASCII files.

The SID are among the family of databases and software tools developed as part of the Healthcare Cost and Utilization Project, a Federal-State-industry partnership sponsored by AHCPR to build a multi-State health care data system for health services research, health policy analysis, and quality measurement and improvement.

As of September 1999, 11 SID files for 1995 and 1996 data are available through an AHCPR-sponsored central coordinator and distributor; 1997 files will be available in spring 2000. Contact the HCUP SID Coordinator (The MEDSTAT Group, 5425 Hollister Avenue, Suite 401, Santa Barbara, CA 93111; phone (805) 681-5876; Fax (805) 681-5888; E-mail for application kits to purchase the 11 centrally available SID and more detailed, descriptive information on the SID. Information on how to obtain uniformly formatted SID files from the other 11 States is also available from the SID Coordinator.

For more online information on databases, software tools, and other products, select HCUP, or send your request via E-mail to

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