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AHRQ releases Nation's most current hospital discharge data

The Agency for Healthcare Research and Quality has released the 1997 Nationwide Inpatient Sample (NIS), the most current publicly available National database of hospital inpatient care use, outcomes, and charges on all patients for all payment sources. This newest NIS release includes hospital discharge information from approximately 7 million inpatient stays at over 1,000 hospitals in 22 States nationwide.

This data set provides researchers with 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 nonclinical variables, including: principal and secondary diagnoses and procedures; patient demographic characteristics such as sex, race, and 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. The NIS also can 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 measure and evaluate 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 (NTIS accession no. PB2000-500006). To order earlier NIS releases, select To preview the NIS, select HCUPNet.

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