Introduction

Purveyor: Agency for Healthcare Research and Quality

Years in the DataCore: 2010-2016

Years of data owned: 2010-2016

Unit of data: Hospital Discharge

Dataset website: https://www.hcup-us.ahrq.gov/db/nation/nrd/nrddbdocumentation.jsp

Public-facing data dictionary: https://www.hcup-us.ahrq.gov/db/nation/nrd/nrddde.jsp 

General description: The NRD is a unique and powerful database designed to support various types of analyses of national readmission rates for all payers and the uninsured. This database addresses a large gap in healthcare data: the lack of nationally representative information on hospital readmissions for all ages. Unweighted, the NRD contains data from approximately 17 million discharges each year. Weighted, it estimates roughly 36 million discharges. 

As a uniform, multi-state weighted database, the NRD promotes comparative studies of healthcare services and supports healthcare policy and research on a variety of topics, including:

  • National readmission rates by diagnosis, procedure, patient demographics, or expected payment source
  • Costs associated with readmissions
  • Reasons for readmissions
  • Impact of health policy changes
  • Readmissions by special populations, including the uninsured

Common Key Linking Variables

Hospital Linking:

  • HCUP NRD hospital identification number (2010-2016)

Patient Linking:

  • HCUP NRD record identifier (KEY_NRD) 2010-2016

Geographic Linking:

  • None

Licensing and Access

All users of HCUP data must complete the HCUP Data Use Agreement (DUA) Training Course and sign an HCUP DUA before receipt of the data. See this website for further information: https://www.hcup-us.ahrq.gov/tech_assist/dua.jsp.

NRD Structure

Core [2010-2016]

Every row of the Core dataset is a hospital discharge.

The primary key of the Core table is:

  • HCUP NRD record identifier (KEY_NRD) 2010-2016

Hospital [2010-2016]

Every row of NIS Hospital is a hospital.

The primary key of the Hospital table is:

  • HCUP NRD hospital identification number (HOSP_NRD) 2010-2016

Severity [2010-2016]

Every Row of severity is All Patient Refined DRG codes from 2015Q4-2016; however, Severity also contains comorbidity data before that. The severity table can be directly mapped to the Core or Hospital tables.

The primary key of the Severity table is KEY_NIS.

DX_PR_GRPS [2010-2015]

Diagnosis and Procedure information contains data about diagnosis and procedures performed during an admission. It can also be mapped to the Core of Hospital tables.

The primary key of the DX_PR_GRPS table is KEY_NIS.

DataCore Staff Errata

5/28/2019: No data errata, data exceptions or data corrections have been issued.

DataCore Staff Errata

5/28/2019: No data errata, data exceptions or data corrections have been issued.

Provenance

The data from HCUP was sent in ascii files (.asc) with associated file specification files. It was found that these file specifications offered an accurate depiction of the data.

For the code used for these processes, email datacore@osumc.edu.

  1. Stata .do files provided by HCUP were used to load the .asc files into Stata. These files were then exported in tab separated value files (.tsv).
  2. The provided file specification files were used in order to create SQL tables to fit the data.
  3. A bulk copy program (BCP) was used in order to upload the .tsv into SQL.
  4. The website https://www.hcup-us.ahrq.gov/db/nation/nrd/nrddde.jsp was used to generate meta data about the dataset fields and was used to generate the data dictionary.