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New National Data Set Provides In-depth Picture of Hospital Care in the U.S.

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Press Release Date: March 22, 1999

The U.S. Agency for Health Care Policy and Research (AHCPR) today released a powerful data set providing an in-depth picture of the use, quality and costs of hospital inpatient care in the United States. Included in the data set is detailed information on topics such as: diagnoses, patient demographics, medical and surgical procedures, diagnostic tests, hospital charges, payment sources and hospital characteristics.

The 1996 data set—the Nationwide Inpatient Sample (NIS)—is a one-of-a-kind database of hospital discharge information from approximately 6.5 million inpatient stays at over 900 hospitals in 19 states across the country. The NIS is the only publicly available database to include payer information, permitting analyses of care covered by private insurance, Medicare, Medicaid and other sources.

The database is a product of the Healthcare Cost and Utilization Project, a Federal-State-industry partnership sponsored by AHCPR to produce standardized, high-quality data for use in measuring and evaluating the impact of changes in the health care system on access to services, quality, outcomes and costs. For researchers and others who want to analyze trends, NIS data sets are available for 1988 through 1996.

"With annual hospital expenditures projected to reach $500 billion within five years, and with concerns today about the quality of health care, it is crucial that policymakers have valid, reliable data for analysis and planning," said AHCPR Administrator, John M. Eisenberg, M.D., MBA. "This data set gives us a look inside the black box of hospital cost and quality. It will help AHCPR achieve its priority of studying and reporting on the outcomes of changes in American health care."

The data set contains more than 100 clinical and non-clinical variables, including: primary and secondary diagnoses and procedures; patient demographic characteristics such as gender, race, median income and zip code; payment source; length of stay; total charges; and admission and discharge status. The large size of the data base permits analysis of rare conditions, such as congenital anomalies, and studies of infrequent procedures, such as organ transplantation. The database fills a special niche in that it also includes information on care provided to the uninsured.

The NIS can be linked with databases containing county-level information, such 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 (AHA) 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 software 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 NIS Release 5 for 1996 is available on CD-ROM with accompanying documentation for $160 from the National Technical Information Service, Port Royal Road, Springfield, VA., 22161 (1-800-553-6847 or 703-605-6000). The product number is PB99-500480. The cost may be higher for customers outside the United States, Canada and Mexico. Data from earlier NIS releases (1988-1995) are also available from NTIS. Select for more information on the HCUP Nationwide Inpatient Sample (NIS).

For additional information, contact AHCPR Public Affairs: Karen Migdail, (301) 427-1855 (

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