HCUP e-News: the electronic newsletter of the Healthcare Cost and Utilization Project

Fall 2018
Issue #56


News and Announcements: Notable news from HCUP
Databases and Products: New database and product releases
Publication Spotlights: Recent works incorporating HCUP data and tools
HCUP Q&A: Answers to your HCUP questions
HCUP Events: Upcoming HCUP conferences and meetings

Missed the last e-News? Read it on the HCUP-US website.

News and Announcements

2016 HCUP Nationwide Databases!

The Agency for Healthcare Research and Quality (AHRQ) has released the 2016 National Inpatient Sample (NIS) and Nationwide Readmissions Database (NRD).

A powerful database that contains data from more than 7 million hospital inpatient records, the NIS is drawn from 46 States and the District of Columbia, covering more than 97 percent of the U.S. population. NIS data can be weighted to produce national estimates, allowing researchers and policymakers to identify, track, and analyze national trends in healthcare utilization, access, charges, quality, and outcomes. The NIS is the largest publicly available inpatient healthcare database in the United States. It includes all patients, regardless of payer—covering Medicare, Medicaid, privately insured, and uninsured patients.

The NRD is a database of all payer hospital inpatient stays that can be used to generate national estimates of readmissions. It addresses a large gap in healthcare data—the lack of nationally representative information on hospital readmissions for all ages. The NRD uses HCUP State Inpatient Databases (SID) with verified patient linkage numbers and includes discharges from community hospitals, excluding rehabilitation and long-term acute care hospitals. It includes discharges for patients with and without repeat hospital visits and those who have died in the hospital. The NRD is designed to be flexible to various types of readmissions analyses. Repeat hospital visits may or may not be related.

The 2016 NIS and NRD are annual calendar-year files with diagnosis and procedure codes reported using only the International Classification of Diseases, Tenth Revision, Clinical Modification/Procedure Coding System (ICD-10-CM/PCS). Therefore, the file structure of the 2016 NIS and NRD is similar to the file structure in data years prior to 2015 with one exception: data elements derived from AHRQ software tools are not available in 2016 because the ICD-10-CM/PCS versions are still under development. For users interested in applying AHRQ software tools to the ICD-10-CM/PCS data in the 2016 NIS and NRD, beta versions of the AHRQ software tools are available for download on the HCUP Tools & Software section of the HCUP User Support (HCUP-US) website.

HCUP nationwide and State-level databases (including the 2016 NIS and NRD) are available for purchase through the HCUP Central Distributor. Earlier years of the NIS and NRD also are available.

The 2016 Kids' Inpatient Database (KID) and Nationwide Emergency Department Sample (NEDS) are scheduled to be released in fall 2018.

Learn About HCUP During the September 5 and 12 Webinars—Sign Up Today!

HCUP’s 2018 Fall Webinar Series will be held on September 5 and 12. The series will feature two 1-hour online sessions dedicated to introducing and explaining the HCUP Project. On September 5, Overview of the HCUP Databases will cover an introduction to the HCUP family of databases. On September 12, Overview of the HCUP Products and Tools will cover the use of HCUP software tools and supplemental files to facilitate and augment research.

The webinars are open to the public. They are geared to health services and policy researchers and other users interested in hospital inpatient and hospital outpatient use and cost data. Each requires separate advance registration, which is now open. Additional details on the webinars are posted on the HCUP Workshops and Webinars page.

AHRQ Is Hosting Fall Hands-On Workshop

The 2018 HCUP Data Users' Workshop will be held in Rockville, Maryland on September 13. This year’s intermediate-level workshop will provide in-depth exposure to HCUP databases and products available to researchers to study opioids, alcohol, and other substances. The presentations will include demonstrations of HCUPnet and Fast Stats as well as an overview of various HCUP publications on substance use. The nationwide databases will be compared to demonstrate the information that can be obtained from each and to help users understand which data sources are best suited to answer their research questions. Attendees will learn how to use HCUP User Support (HCUP-US) documentation to their advantage when developing analyses.

Registration for the 2018 workshop has reached capacity and is now closed. For more information and workshop details, please visit the HCUP Workshops and Webinars Homepage.

HCUP Fast Stats New Interactive Opioid-Related Hospital Use Map and Data Update

AHRQ released new information in HCUP Fast StatsInteractive U.S. Map of Opioid-Related Hospital Use. This new map provides annual rates of opioid-related inpatient stays or emergency department (ED) visits per 100,000 population. States are color-coded to identify each State's opioid-related inpatient or ED rate relative to the distribution across all States providing data in 2015. AHRQ also has released an update of State Trends in Hospital Use by Payer to include new inpatient and ED data. Since the last update in November 2017, the Inpatient Stay Trends by Payer section now includes additional 2017 inpatient data (for 19 States) and 2016 inpatient data (for 41 States). The ED Visit Trends by Payer section now includes 2016 ED data (for 24 States) and additional 2015 ED data (for 7 States).

For additional information, please refer to the Fast Stats Frequently Asked Questions page or contact HCUP User Support.

HCUP's Outstanding Article of the Year Award Winners Announced!

Authors of two studies received the eighth annual Outstanding Article of the Year Award at AcademyHealth's Annual Research Meeting (ARM) Exit Disclaimer in June 2018. Each year, AHRQ recognizes researchers published in peer-reviewed journals who used HCUP databases to explore and address healthcare research topics and issues. Honored work demonstrates how HCUP has contributed to these investigations.

Users can find a list of prior recipients of the HCUP Outstanding Article of the Year Award and gain additional information on the selection process by visiting the Outstanding Article of the Year Award Page on the HCUP-US website. The award recipients also are showcased in the Publication Spotlights section of this newsletter.

Databases and Products

Recently Released: 2016 State Databases and Additional 2013-2015 Databases

Since June 2018, the following State Databases have been released:

In addition, the 2016 National Inpatient Sample (NIS) and Nationwide Readmissions Database (NRD) have been released. For database purchasing questions, please contact the HCUP Central Distributor.

Complete listings of available databases by year can be found in the Database Catalog on the HCUP-US website. Databases can be purchased online through the HCUP Central Distributor, and aggregated national and selected State statistics can be accessed via HCUPnet.

Publication Spotlights

New HCUP Statistical Briefs Posted on HCUP-US

Since June 2018, the following HCUP Statistical Briefs have been released:

To access these and other Statistical Briefs, please visit the Statistical Briefs page on the HCUP-US website.

Publications Using HCUP Data

HCUP Outstanding Article of the Year Award: Clinical Winner:

Secemsky EA, Schermerhorn M, Carroll BJ, Kennedy KF, Shen C, Valsdottir LR, Landon B, Yeh RW. Readmissions After Revascularization Procedures for Peripheral Arterial Disease: A Nationwide Cohort Study. Annals of Internal Medicine. 2018 Jan 16;168(2):93-99.

This study used the 2014 Nationwide Readmissions Database (NRD) to evaluate nationwide readmissions after peripheral arterial revascularization for peripheral arterial disease and to explore causes and variances in readmission risk by institution. The article abstract is available via PubMed.

HCUP Outstanding Article of the Year Award: Policy Winner:

Wherry LR, Miller S, Robert Kaestner R, and Meyer BD. Childhood Medicaid Coverage and Later-Life Health Care Utilization. Review of Economics and Statistics. 2017 Apr; 100.

This study used the State Inpatient Database (SID) and State Emergency Department Database (SEDD) for 1999 from Arizona, Hawaii, Iowa, New York, Oregon, and Wisconsin, and 2009 from Arizona, Arkansas, Colorado, Hawaii, Iowa, Kentucky, Maryland, Michigan, Nebraska, New York, North Carolina, Oregon, South Dakota, Utah, Vermont, and Wisconsin to examine the long-term effects of childhood Medicaid coverage on adult utilization of hospital and ED care. The article abstract is available via The MIT Press. Exit Disclaimer

To read additional recently published articles featuring HCUP data, please visit the Research Spotlights page on the HCUP-US website.


Question: I am working on an analysis that is specific to trends in opioid-related inpatient stays and emergency department (ED) visits. Before I get started, I have a few questions about the resources that HCUP has available.


My analysis will include both ICD-9-CM and ICD-10-CM/PCS codes. Does HCUP have any resources available to help me with the transition from ICD-9-CM to ICD-10-CM/PCS?

The ICD-10-CM/PCS Resources Section on the HCUP User Support (HCUP-US) website summarizes key issues for researchers using HCUP and other administrative databases that include ICD-10-CM/PCS coding. The page documents key differences in the structure of HCUP databases, provides general guidance and forewarning to users analyzing outcomes that may be affected by the transition to the ICD-10-CM/PCS coding system, and lists other related Web resources.

For opioid research specifically, you may be interested in reviewing the following two case studies: Trends in Opioid-Related Inpatient Stays Shifted After the US Transitioned to ICD-10-CM Diagnosis Coding in 2015 and Preliminary Case Study: Exploring How Opioid-Related Diagnosis Codes Translate from ICD-9-CM to ICD-10-CM.

Given that I am interested in trends in opioid-related inpatient stays and ED visits, which HCUP Nationwide database should I be using – the NIS, NEDS, or both?

The National Inpatient Sample (NIS) is sampled from the State Inpatient Databases (SID) and provides national estimates of inpatient stays, including ED visits that resulted in admission to the same hospital (i.e., ED admissions). The Nationwide Emergency Department Sample (NEDS) provides national estimates of ED visits. It is constructed using records from (1) the HCUP State Emergency Department Databases (SEDD), which capture information on ED encounters that do not result in an admission (i.e., treat-and-release encounters and transfers to other hospitals), and (2) the SID, which (as noted above) contain information on patients initially seen in the ED and then admitted to the same hospital.

If you are interested in opioid-related trends for all inpatient stays, including ED admissions, then you would want to use the NIS. Similarly, if you are interested in all ED visits (i.e., treat and release and ED admissions), then you would want to use the NEDS. However, because both the NIS and the NEDS contain SID records for which the patient initially was seen in the ED and then admitted to the same hospital, we recommend subsetting the NEDS to avoid double counting. Specifically, ED treat-and-release records could be selected from the NEDS using the HCUP data element HCUPFILE, which identifies the source of the ED record: the HCUP SID or the SEDD. Because ED admissions already are represented in the NIS, you would want to select all records where HCUPFILE is equal to SEDD.

I noticed that some HCUP resources, such as HCUP Fast Stats, present opioid-related statistics as population-based rates as opposed to discharge or ED visit counts. In what cases might it be better to use population-based rates?

Both national and State-level estimates are provided in the Opioid-Related Hospital Use topic of Fast Stats; therefore, rates per 100,000 population were chosen to make the estimates comparable. In addition, reporting by rates allows comparisons across population subgroups, such as age, sex, and patient location.

Another case where population-based rates are recommended is specific to the reporting of trends from ICD-9-CM to ICD-10-CM/PCS in the 2015 data year. If an analysis is based on diagnosis and procedure codes (i.e., uses ICD-9-CM and ICD-10-CM/PCS codes) and a discontinuity in the frequency of cases within a diagnosis or procedure code or category of codes is observed across the two coding systems, it is recommended that data are reported a way that acknowledges this discontinuity. Specifically, users may wish to report information from only one of the coding schemes, such as ICD-9-CM codes from January 1 through September 30, 2015. The resulting counts will not be based on annual numbers; however, population-based rates can be used by multiplying the denominator by .75 to reflect that only three quarters of the 2015 data were used. Additional information is available in the report, HCUP Recommendations for Reporting Trends Using ICD-9-CM and ICD-10-CM/PCS Data on the ICD-10-CM/PCS Resource Section of HCUP-US.

HCUP Events

For a complete list of HCUP presentations and events, visit the HCUP Events Calendar.

The HCUP e-News is available online at the HCUP-US website and distributed via the HCUP Mailing List.

For more information and questions regarding the HCUP e-News, please email hcup@ahrq.gov