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AHRQ Releases Nation's Most Current Hospital Discharge Data

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Press Release Date: March 15, 2000

The U.S. Agency for Healthcare Research and Quality (AHRQ) today announced the release of its 1997 Nationwide Inpatient Sample (NIS)—the most current publicly available national database of hospital inpatient care use, outcomes and charges on all patients, regardless of payment source. This newest NIS release includes hospital discharge information from approximately 7 million inpatient stays at over 1,000 hospitals in 22 states nationwide.

"Increasingly, the health services research community is using the NIS to uncover trends that have significant public policy and management implications for inpatient care," said AHRQ Director John M. Eisenberg, M.D. "This data set gives researchers an evidence base to understand patterns of hospitalization by Americans as a whole, or by specific groups, such as children and the elderly, and to assess outcomes as well as hospital charges."

The NIS is the only publicly available database that includes charge information from all payers (Medicare, Medicaid, private insurers) as well as data on the uninsured. Like previous releases, the 1997 NIS contains more than 100 clinical and non-clinical variables, including: principal and secondary diagnoses and procedures; patient demographic characteristics such as gender, race, median income; payment source; length of stay; total charges; and discharge status. The large size of the database permits analysis of rare conditions, such as congenital anomalies, and studies of infrequent procedures, such as organ transplantation. For researchers who want to analyze trends, NIS data sets are available for 1988 through 1997.

The NIS can be linked with databases containing county-level information, such as the Bureau of Health Professions Area Resource File—a database of the U.S. Health Resources and Services Administration. It can also be linked with descriptive hospital data from the American Hospital Association's Annual Survey of Hospitals.

The data set can be run on desktop computers and comes in ASCII format for ease of use with numerous off-the-shelf products, including SAS and SPSS. NIS also includes weights for producing national and regional estimates and comes with full documentation in Adobe® Acrobat®. SAS and SPSS users are provided programs for converting ASCII files.

The data set is part of a family of products produced by the Healthcare Cost and Utilization Project (HCUP), a Federal-State-industry partnership sponsored by AHRQ. A key goal of the partnership is producing standardized, high-quality data that measures and evaluates changes in the health care system.

The 1997 NIS is available on CD-ROM with accompanying documentation for $160 from the National Technical Information Service, 5285 Port Royal Road, Springfield, VA, 22161 (1-800-553-6847 or 703-605-6000). The product number is PB2000-500006. To order earlier NIS releases, visit the NTIS Web site at Interested users can preview the NIS online with HCUPnet at

For more information, please contact AHRQ Public Affairs, (301) 427-1364: Louise Arnheim (301) 427-1271.

The information on this page is archived and provided for reference purposes only.


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