NRD Database Documentation

The HCUP Nationwide Readmissions Database (NRD) is a set of inpatient databases in the HCUP family designed for readmission analyses. These HCUP databases are created by AHRQ through a Federal-State-Industry partnership.

The Nationwide Readmissions Database (NRD) is a unique and powerful database designed to support various types of analyses of national readmission rates for all patients regardless of the expected payer for the hospital stay. The NRD includes discharges for patients with and without repeat hospital visits in a year and those who have died in the hospital. Repeat stays may or may not be related. The criteria to determine the relationship between hospital admissions is left to the analyst using the NRD. This database addresses a large gap in healthcare data - the lack of nationally representative information on hospital readmissions for all ages.

The links below provide detailed documentation for the NRD, from a high-level Overview to all the detailed specifications, restrictions, and resources necessary for researchers working and publishing with the NRD.

Description of NRD Files

NRD Overview

HCUP Partners in the NRD

Introduction to the NRD, 2010-2018 (PDF file, 1.0 MB; HTML)

Prior Years

NRD Related Reports
Checklist for Working with the NRD

Restrictions on Use

HCUP Data Use Agreement Training
Data Use Agreement for the Nationwide Databases (PDF file, 85 KB; HTML)
Requirements for Publishing with HCUP Data

File Specifications and Load Programs

Data Elements

Additional Resources for Data Elements

HCUP Quality Control Procedures (PDF file, 383 KB; HTML)
HCUP Coding Practices (PDF file, 138 KB; HTML)
HCUP Hospital Identifiers (PDF file, 162 KB; HTML)

ICD-10-CM/PCS Data Included in the NRD Starting With 2015

NRD Changes Beginning Data Year 2016 (PDF file, 216 KB)
Caution: 2015 NRD includes ICD-9-CM and ICD-10-CM/PCS

2015 NRD Revised File Structure and New Data Elements (PDF file, 553 KB)

Additional ICD-10-CM/PCS Resources
Tutorial for Loading HCUP Software Tools for ICD-10-CM/PCS

Known Data Issues

Limitations on Using the NRD (PDF file, 149 KB)
NRD, 2010-2012 (PDF file, 278 KB)
NRD, 2010-2013 (PDF file, 88 KB)
NRD, 2014 (PDF file, 31 KB)

HCUP Tools: Labels and Formats

Clinical Classifications Software (CCS)
Format Programs

DRG Formats Program (TXT file, 1.7 MB) Creates SAS formats to label the values of each DRG and MDC category
HCUP Formats Program (TXT file, 63 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, 39 KB) Creates SAS formats to label the values of HCUP Diagnosis and Procedure Groups data elements, including Clinical Classifications Software (CCS) 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, 11.8 MB) Creates SAS formats to label the values of ICD-10-CM Diagnoses and Procedures
Severity Formats Program (TXT file, 796 KB) Creates SAS formats to label the values of data elements in HCUP Severity Files

Obtaining HCUP Data

Purchase HCUP data from the HCUP Central Distributor

Internet Citation: NRD Database Documentation. Healthcare Cost and Utilization Project (HCUP). December 2020. Agency for Healthcare Research and Quality, Rockville, MD. www.hcup-us.ahrq.gov/db/nation/nrd/nrddbdocumentation.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 12/1/20