NIS Database Documentation

The National (Nationwide) Inpatient Sample (NIS) is the largest publicly available all-payer inpatient care database in the United States, containing data on more than seven million hospital stays. Its large sample size is ideal for developing national and regional estimates and enables analyses of rare conditions, uncommon treatments, and special populations.

The following links provide detailed documentation for the NIS, from a high-level Overview to all the detailed specifications, restrictions, and resources necessary for researchers working and publishing with the NIS.
 
Description of NIS Database Restrictions on Use File Specifications and Load Programs Data Elements Additional Resources for Data Elements   ICD-10-CM/PCS Data Included in the NIS Starting With 2015 2012 NIS Redesign Known Data Issues NIS Supplemental Files HCUP Tools: Labels and Formats
  • Format Programs
    • DRG Formats Program (TXT file, 1.5 MB) Creates SAS formats to label the values of each DRG and MDC category
    • HCUP Formats Program (TXT file, 108 KB) Creates SAS formats to label the values of selected categorical data elements in HCUP files
    • HCUP Diagnosis and Procedure Groups Formats Program (TXT file, 8 KB) Creates SAS formats to label the values of HCUP Diagnosis and Procedure Groups data elements, including Clinical Classifications Software Refined (CCSR) data elements
    • ICD-9-CM Formats Program (TXT file, 910 KB) Creates SAS formats to label the values of ICD-9-CM Diagnoses and Procedures
    • ICD-10-CM Formats Program (TXT file, 12.2 MB) Creates SAS formats to label the values of ICD-10-CM Diagnoses and Procedures
    • Severity Formats Program (TXT file, 816 KB) Creates SAS formats to label the values of data elements in HCUP Severity Files
Obtaining HCUP Data

Internet Citation: HCUP NIS Database Documentation. Healthcare Cost and Utilization Project (HCUP). September 2021. Agency for Healthcare Research and Quality, Rockville, MD. www.hcup-us.ahrq.gov/db/nation/nis/nisdbdocumentation.jsp.
Are you having problems viewing or printing pages on this website?
If you have comments, suggestions, and/or questions, please contact hcup@ahrq.gov.
Privacy Notice, Viewers & Players
Last modified 9/10/21