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

Summer 2018
Issue #55


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 Web site.

News and Announcements

Coming Soon: 2016 National Inpatient Sample (NIS), Kids' Inpatient Database (KID), Nationwide Readmissions Database (NRD), and Nationwide Emergency Department Sample (NEDS)

The 2016 HCUP nationwide databases will be individually available from late summer through fall of 2018. This will include the National Inpatient Sample (NIS), Kids’ Inpatient Database (KID), Nationwide Emergency Department Sample (NEDS), and the Nationwide Readmissions Database (NRD). The databases contain encounter-level information on all patients, regardless of payer, including individuals covered by Medicare, Medicaid, or private insurance and the uninsured.

Once data for each participating State have been received for the year, the nationwide database production begins. The NIS is typically released first and is sampled from all HCUP State Inpatient Databases (SID). The NIS is the largest publicly available all-payer inpatient care database in the United States, yielding national estimates of hospital inpatient stays. Also sampled from the SID, but specifically pediatric discharges, the development of the KID typically follows. The KID is the largest publicly available all-payer inpatient care database for children in the United States, yielding national estimates of hospital inpatient stays for patients under 21 years of age. The NRD is developed simultaneously and drawn from SID with verified patient linkage numbers that can be used to track patients across hospitals within a State while adhering to strict privacy guidelines. The NRD is a database of all-payer hospital inpatient stays that can be used to examine national estimates of readmissions. To enumerate all ED visits, the NEDS is sampled using records from both the SID and SEDD. As such, the NEDS is typically released after the NIS, KID, and NRD. The NEDS is the largest all-payer emergency department (ED) database in the United States, yielding national estimates of ED visits.

The 2016 NIS, KID, NEDS, and NRD will be available for purchase through the HCUP Central Distributor. For up-to-date information on database releases, please subscribe to the HCUP Mailing List.

HCUP Resources for Opioid and Substance Use Research

As health care utilization rates for opioid and substance use encounters continue to rise, HCUP has developed valuable national and State-level data products and tools to assist researchers in understanding more about this nationwide epidemic.

Several HCUP Statistical Briefs have been published on topics on opioid and drug-related inpatient stays and emergency department visits. The following are some recent publications:

HCUP Infographics, visual representations of data found in HCUP Stat Briefs, inform researchers about important statistics through the use of tables, charts, and images. Numerous infographics have been created on opioid and substance use topics. The following is a complete list of these infographics:

Case Studies authored by HCUP researchers related to opioid use have been published on both the HCUP-US Web site and in peer-reviewed journals. The following two studies used ICD-10-CM coding to analyze opioid use.

The HCUP Fast Stats - Opioid-Related Hospital Use topic provides trends in opioid-related inpatient stays and emergency department visits at the national and State levels. Statistics are reported by quarter for participating States for 2008–2017.

HCUPnet provides community-level pathways for county-level comparisons of hospitalization rates for opioids, alcohol, stimulants, and other drugs. A recent addition of 2014 data for the Stays for Alcohol and Other Drugs classification is available for select States.

For more in-depth research on opioids and substance use, users can purchase the HCUP State and nationwide databases by contacting the HCUP Central Distributor. The nationwide databases can be used to identify and analyze national trends, and the State Databases allow researchers to investigate State-specific and multi-State trends in health care.

For questions or feedback regarding opioid and substance use-related research, please contact HCUP User Support.

HCUP Fast Stats Data Update

The Agency for Healthcare Research and Quality (AHRQ) updated information in the Opioid-Related Hospital Use topic in HCUP Fast Stats. This Fast Stats update adds 2015 emergency department data for 3 States, 2016 inpatient data for 24 States, 2016 emergency department data for 15 States, and 2017 inpatient data for 16 States.

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

HCUP's Outstanding Article of the Year Awards

Two studies will receive the eighth annual HCUP Outstanding Article of the Year Award at the AcademyHealth Annual Research Meeting. Exit Disclaimer The Award honors articles published in peer-reviewed journals in 2017 that used HCUP data to explore and address health care research topics and issues. The award recipients will be announced during the HCUP Overview presentation on June 26 at 8:00 a.m.

Since 2010, AHRQ has recognized exceptional research conducted using the HCUP databases in the clinical and health policy arenas. This research continues to enhance public conversation about health care costs, outcomes, and trends. Over the past 8 years, the Awards have come to be recognized as a distinguished honor among health services researchers with a variety of clinical insights, economic interests, and policy backgrounds. AHRQ is proud of the important work being done with HCUP data.

Additional information is available in the HCUP Calendar of Events.

HCUP Data Users' Workshop on September 13

On September 13, AHRQ will sponsor a full-day, intermediate-level HCUP data users’ workshop titled An In-Depth Exploration of HCUP Resources That Can Be Used to Study Hospital Utilization for Opioids, Alcohol, and Other Substances at its headquarters in Rockville, Maryland. This workshop will teach health services researchers and analysts how to use or improve their use of HCUP databases and products within the context of the opioid and substance use topic.

The workshop will be open to the public at no charge. Space will be limited. Registration information and the workshop description will be available later this summer on the HCUP Workshops and Webinars page.

Learn About HCUP at the September 5 and 12 Webinars

On September 5, a webinar Overview of the HCUP Databases will cover an introduction to the HCUP family of databases. On September 12, a second webinar 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 will be open to the public at no charge. Each will require separate advance registration. Registration information and webinar descriptions will be available in August on the HCUP Workshops and Webinars page.

Databases and Products

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

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

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

For database purchasing questions, please contact the HCUP Central Distributor.

Publication Spotlights

New HCUP Statistical Briefs Posted on HCUP-US

Since March 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 Web site.

New HCUP Method Series Report Now Available

Since March 2018, the following Methods Series Report has been released:

Method Series Report #2018-01: Methods Applying AHRQ Quality Indicators to Healthcare Cost and Utilization Project (HCUP) Data for the 2017 National Healthcare Quality and Disparities Report (QDR) describes the preparation of the HCUP databases for data years 2000–2015 for use in the 2017 QDR, the steps taken to apply the AHRQ Quality Indicators (QIs) to the HCUP data, and other analyses based on HCUP data that are not specific to the QIs but were developed for use in the 2017 QDR.

This report and other HCUP reports can be found on the HCUP Reports page.

Publications Using HCUP Data

França UL, McManus ML. Frequency, trends, and antecedents of severe maternal depression after three million U.S. births. PLoS One. 2018;13(2).

This study used the 2005–2012 State Inpatient Databases (SID), State Ambulatory Surgery and Services Databases (SASD), and State Emergency Department Databases (SEDD) from California (through 2011) and Florida to identify trends and provide treatment recommendations for hospital encounters during pregnancy and 1 year following delivery associated with postpartum depression. The article abstract is available via PubMed.

Batty M, Ippolito, B. Financial incentives, hospital care, and health outcomes: evidence from fair pricing laws. Am Econ J: Econ Policy. 2017;9(2):28–56.

This study uses the 2003–2011 Nationwide Inpatient Sample (NIS) and the 2005–2009 State Inpatient Database (SID) for California to evaluate the relationship between fair pricing laws for health care providers and the related quality of care delivered to uninsured individuals. The article abstract is available via American Economic Journal: Economic Policy. Exit Disclaimer

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


Question: I am a new user of HCUP databases and products and have some general questions about the types of analyses that certain databases and/or products support.


I am interested in doing an analysis on pediatric inpatient stays, and I am wondering which HCUP database I should use—the NIS or the KID?

Both the NIS and the KID contain a sample of pediatric discharges and therefore can be used for analyses of pediatric inpatient stays. The chief benefit associated with using the KID is that, because of its sample design, rare conditions (e.g., congenital anomalies) and uncommon treatments (e.g., organ transplantation) can be analyzed. The KID is best used for the study of nonbirth and complicated birth medical conditions. Because of the sampling design of the KID, research questions involving normal births are best analyzed using the NIS.

If I am interested in all emergency department visits, including those in which the patient was admitted to the same hospital, do I need to use both the NIS and the NEDS?

No, you would only require the NEDS. The NEDS provides national estimates of hospital-owned emergency department visits. The database is constructed using records from (1) the SEDD, which capture information on emergency department encounters that do not result in an admission (i.e., treat-and-release encounters and transfers to other hospitals), and (2) the SID, which contain information on patients initially seen in the emergency department and then admitted to the same hospital.

It is my understanding that the NIS is sampled from the SID. In that case, could I use the NIS for a State-level analysis?

Although you are correct that the NIS is sampled from the SID, the NIS cannot support State-level analyses. For confidentiality, the NIS does not include State-level identifiers. Instead, users can employ the SID for State-level estimates.

I would like to study readmissions; specifically, I would like to be able to track patients over time. Can this be done with the NRD? Additionally, how would I go about identifying readmissions?

Although patients can be tracked within a single year of the NRD, it is not possible with the NRD to track patients across years. Each year of the NRD is considered as a separate sample—for instance, 2 years of the NRD cannot be combined to create a 24-month database.

Instead, we recommend using the SID and specifically those that include the HCUP Supplemental Variables for Revisit Analyses or the revisit variables. For additional information on the availability of the revisit variables, consult Appendix A in User Guide: HCUP Supplemental Variables for Revisit Analyses. Appendix C of this document includes consistency of person identifiers across years by State. If your intent is to be able to track patients across years within a specific State, you will need to ensure that the percentage of unique values of visitLink that appear in consecutive data years of the SID is reliable. If the percentage is low or different than other pairs of years, it is a good indication that the visitLink cannot be used to track patients across those data years.

Criteria to determine the relationship between multiple hospital admissions for an individual patient are left to the analyst using the NRD or SID with revisit variables. These criteria are based on the intent of the user’s analysis. Neither the NIS nor the SID include a data element that directly identifies a readmission.

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 Web site and distributed via the HCUP Mailing List.

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