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

Winter 2021
Issue #69


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

News and Announcements

HCUP Software Tools for ICD-10-CM/PCS Undergo Fiscal Year 2022 Updates

The Healthcare Cost and Utilization Project (HCUP) software tools for the International Classification of Diseases, Tenth Revision, Clinical Modification/Procedure Coding System (ICD-10-CM/PCS) are updated annually by Federal fiscal year (FY) to accommodate new or revised ICD-10-CM/PCS codes, as well as to add corrections or modifications based on new clinical guidance for the use of ICD-10-CM/PCS codes. The Agency for Healthcare Research and Quality (AHRQ) has released the following updated HCUP software tools valid for ICD-10-CM/PCS codes through FY 2022:

See the Research Tools page of the HCUP-US website for more information on the changes to each tool.

HCUP 2019 Nationwide Databases Released

In October, AHRQ released the 2019 Kids' Inpatient Database (KID), Nationwide Ambulatory Surgery Sample (NASS), Nationwide Emergency Department Sample (NEDS), and Nationwide Readmissions Database (NRD). The KID, NASS, NEDS, and NRD are produced as part of HCUP to enable research on healthcare issues and trends that are of interest to policymakers, researchers, administrators, and consumers.

The KID is the largest publicly available all-payer pediatric inpatient care database that can be used to produce national estimates of hospital inpatient stays for children in the United States. Drawn from the HCUP State Inpatient Databases (SID), the KID includes more than 3 million pediatric hospital inpatient records from 48 States and the District of Columbia, covering 98 percent of the U.S. population.

The NASS produces national estimates of major ambulatory surgery encounters in hospital-owned facilities. The NASS contains clinical and resource-use information that is included in a typical hospital-owned facility record, including patient characteristics, clinical diagnostic and surgical procedure codes, disposition of patients, total charges, expected source of payment, and facility characteristics. Beginning with the 2019 data year, the NASS now includes information on patient race and ethnicity.

The NEDS generates national estimates about emergency department (ED) visits across the country, regardless of whether the visit results in admission. One of the most distinctive features of the NEDS is its large sample size, which allows for analysis across hospital types and the study of relatively uncommon disorders and procedures. Beginning with the 2019 data year, the NEDS now includes information on patient race and ethnicity.

The NRD is 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.

The 2019 KID, NASS, NEDS, and NRD are available for purchase through the HCUP Central Distributor. Earlier years of the nationwide databases also are available.

Cost-to-Charge Ratio (CCR) Files for the Nationwide Emergency Department Sample (NEDS)

The HCUP Cost-to-Charge Ratio (CCR) Files for the Nationwide Emergency Department Sample (NEDS) (CCR-NEDS Files) are now available. HCUP CCR Files are hospital-level files designed to supplement the data elements in HCUP inpatient and emergency department (ED) databases.

The HCUP CCR for ED Files can be used to estimate the cost of resource use for ED visits based on the reported total charge and the cost-to-charge ratios provided in the supplemental files. Costs reflect the actual expenses incurred in the production of hospital services, such as wages, supplies, and utility costs. Hospital charges indicate the amount the hospital billed for the entire ED visit and do not include professional (physician) fees, how much hospital services cost, or the specific amounts that hospitals received in payment. For some analyses, users may be interested in estimating how hospital charges translate into actual costs. The HCUP CCR for ED Files enable this conversion.

The 2012–2019 CCR-NEDS Files can be accessed through the HCUP Central Distributor. Additional information is located on the Cost-to-Charge Ratio Files web page.

New Data Added to HCUP Data Visualization and HCUP Summary Trend Tables

AHRQ has updated the HCUP Data Visualization of Inpatient Trends in COVID-19 and Other Conditions and the HCUP Summary Trend Tables to include the first quarter of 2021 data for 11 States and full-year 2020 data for 29 States. The HCUP Data Visualization displays State-specific monthly trends in inpatient stays related to COVID-19 and other conditions. It also facilitates comparisons of the number of hospital discharges, the average length of stays, and in-hospital mortality rates across patient/stay characteristics and States. An image of the HCUP Data Visualization below displays the number of discharges for COVID-19-related inpatient stays for all selected States from April 2020 through June 2021.

Image of HCUP Data Visualization Number of Discharges, COVID-19 Related Inpatient Stays, All Patients in Selected States.

The HCUP Summary Trend Tables are tabulations containing State-specific monthly trends in hospital utilization and are available for users in a downloadable Microsoft® Excel format. Information is derived from the HCUP State Inpatient Databases (SID) and HCUP State Emergency Department Databases (SEDD).

For more details on these HCUP resources, including access to methods and underlying data tables, please visit the Reports section of the HCUP-US website.

HCUP Fast Stats Data Update

AHRQ has released new information in HCUP Fast Stats. The State Trends in Hospital Use by Payer topic has been updated to include 2019 inpatient data for 30 States, 2020 inpatient data for 28 States, and 2021 quarter 1 inpatient data for 10 States. This update also adds 2019 emergency department (ED) data for 23 States and 2020 ED data for 16 States.

Image of Fast Stats Homepage

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

Updates to HCUP Online Tutorial Series

Two HCUP Online Tutorials have been revised to reflect project updates: Load and Check HCUP Data and HCUP Software Tools.

These tutorials, along with other helpful HCUP interactive courses, can be found on the HCUP Online Tutorial Series home page.

Databases and Products

Recently Released: 2019–2020 and Additional 2018 State Databases

Since September 2021, the following State databases have been released:

In addition, the 2019 Kids Inpatient Database (KID), Nationwide Ambulatory Surgery Sample (NASS), Nationwide Emergency Department Sample (NEDS), and Nationwide Readmissions Database (NRD) have been released. 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

The following HCUP Statistical Briefs will be released soon:

Additionally, updates to the Statistical Briefs on changes in hospitalizations and in-hospital deaths during the COVID-19 pandemic will be released soon with more recent data and more States included.

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

New HCUP Methods Series Reports Available

Since September 2021, the following Method Series Reports have been released:

These and other HCUP reports can be found on the HCUP Reports page of the HCUP-US website.


Question: I am interested in using the recently released Elixhauser Comorbidity Indices Refined for ICD-10-CM for an analysis. I have some questions about the newly updated tool before I begin using it.


How are the Elixhauser Comorbidity Indices Refined for ICD-10-CM different from the Elixhauser Comorbidity Index for ICD-9-CM?

The Elixhauser Comorbidity Indices were originally developed using ICD-9-CM diagnosis codes and adult (ages 18 years and older), nonmaternal inpatient discharge data.1 The development of the ICD-10-CM version of the indices was consistent with the methodology used for the ICD-9-CM version of the tool but used more recent (2018) data that contain ICD-10-CM diagnosis codes.

1 Moore BJ, White S, Washington R, Coenen N, Elixhauser A. Identifying increased risk of readmission and in-hospital mortality using hospital administrative data: the AHRQ Elixhauser Comorbidity Index. Med Care. 2017;55(7):698-705.

I see that the Elixhauser Comorbidity Software Refined for ICD-10-CM can be used with outpatient administrative data beginning v2021.1. Is this the same for the indices?

Additional work needs to be done to understand using the indices for studying outpatient encounters. For that reason, we do not recommend applying the indices for analyses of outpatient administrative data.

Can I assign the indices to my administrative data if only some of the comorbidity measures are assigned? My administrative data do not include indicators that a diagnosis was present on admission, which are required for 18 of the comorbidity measures.

The indices depend on all 38 comorbidity measures being coded in the data. Therefore, your data must include present on admission indicators.

Can I compare the indices across years, specifically the indices for ICD-9-CM with the indices for ICD-10-CM?

The Elixhauser Comorbidity Software Refined for ICD-10-CM is different from the ICD-9-CM version in its approach to identifying comorbidities and the number of comorbidities identified. Given that the indices are based on the 38 individual comorbidity measures, it is best to not compare the indices across coding systems. Additional information on the changes made to the Elixhauser Comorbidity Software Refined for ICD-10-CM is available in the User Guide for the tool.

HCUP Events

There are no upcoming events at this time. Please refer to the HCUP Events Calendar for updates on future activities.

The HCUP e-News is available online on 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