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New national data set provides in-depth picture of hospital care in the United States

Researchers now have access to a powerful new data set that provides an in-depth picture of the use, quality, and costs of hospital inpatient care in the United States. This data set, which is available from the Agency for Health Care Policy and Research, includes 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.

The data set contains more than 100 clinical and nonclinical variables, including primary and secondary diagnoses and procedures; patient demographic characteristics such as sex, race, median income, and zip code; payment source; length of stay; total charges; and admission and discharge status. The large amount of data contained in the NIS 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 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 with 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. The NTIS accession number is PB99-500480. The cost may be higher for customers outside the United States, Canada, and Mexico. Data from earlier NIS releases (1988 through 1995) also are available from National Technical Information Service.

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