This page provides answers to commonly asked questions about obtaining and using the
Healthcare Cost and Utilization Project (HCUP) databases, software tools,
supplemental files, and other products. It also covers certain questions about data
use restrictions and publishing with the data. Links throughout these FAQs direct
you to the complete documentation resources for working with HCUP data. If
you still have questions, please use the following contact information as a
guide to identify the correct support resource.
For questions about using the HCUP databases, software tools, supplemental files,
and other products, or about data use restrictions and publishing with the data,
contact HCUP User Support at HCUP@ahrq.gov.
Additional information regarding HCUP User Support is located in the About HCUP User Support section below.
For questions concerning HCUP database purchases, current HCUP database orders
and invoices, downloading nationwide HCUP databases, unzipping State or
nationwide HCUP database products, the submission of required HCUP Data Use
Agreements (DUAs), training certificate codes, or data re-use requests, please
review the HCUP Central Distributor FAQs, or
contact the HCUP Central Distributor at HCUP@ahrq.gov.
For questions about using the AHRQ Quality Indicators (QIs), visit the AHRQualityIndicators™
page or contact QIsupport@ahrq.hhs.gov.
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- What is HCUP?
The Healthcare Cost and
Utilization Project (called "H-CUP") is a family of healthcare
databases, software tools, and products developed through a
Federal-State-Industry partnership and sponsored by the Agency for Healthcare Research
and Quality (AHRQ). HCUP databases bring together the data collection
efforts of State data organizations, hospital associations, private data
organizations, and the Federal government to create a national information
resource of encounter-level healthcare data.
HCUP includes the largest
collection of longitudinal hospital care data in the United States, with
all-payer, encounter-level information beginning in 1988. HCUP is derived from
administrative data originally collected for billing purposes. These databases
enable research on a broad range of health policy issues, including cost and
quality of health services, medical practice patterns, access to healthcare
programs, and outcomes of treatments at the national, State, and local market
levels.
HCUP also offers
free research tools for health services researchers and decision makers
using HCUP and other similar administrative databases. The HCUP Software Tools
can be applied to HCUP and other administrative databases to create new data
elements from existing data, thereby enhancing a researcher's ability to conduct
analyses. The HCUP Supplemental Files are available for use with the HCUP
databases to enhance a researcher's ability to conduct analyses. These files are
not applicable to other administrative databases.
HCUP also offers free
online query tools. HCUPnet
is
an online query system that provides
immediate access to statistics on hospital inpatient, emergency department,
costs, and readmissions. HCUP Fast Stats is an online query tool that uses visual
displays to compare national- or State-level statistics on a range of healthcare
topics. These visual displays include stand-alone graphs, trend figures, or
simple tables to convey complex information at a glance.
HCUP offers a
variety of online reports, including HCUP Statistical Briefs which present simple,
descriptive statistics on a variety of specific topics.
For additional
information, please visit the Overview
of HCUP page and take the Online HCUP
Overview Course.
- What types of healthcare settings are captured in HCUP data?
The HCUP databases are built from hospital administrative data (i.e.,
hospital billing records). The databases cover hospital inpatient care,
outpatient emergency department care, and ambulatory surgery and other
outpatient services from hospital-owned facilities. Some State Ambulatory
Surgery and Services Databases (SASD) include ambulatory surgery and services
data from facilities not owned by a hospital. HCUP does not include services
provided in physician offices, and does not contain complete or reliable
pharmacy, laboratory, pathology, or radiology information.
- Under the Health Insurance Portability and Accountability Act (HIPAA)
Privacy Rule, how are the HCUP databases defined?
The HCUP
databases are consistent with the definition of limited data
sets under the HIPAA
Privacy
Rule and contain no direct patient identifiers. HCUP Data Use Agreement (DUA)
training and a signed DUA are required to purchase and/or use the HCUP
databases.
- What is HCUP's unit of analysis?
The unit of analysis
in the HCUP databases is the
discharge record, not individual patients.
- How can I keep informed about HCUP activities and product
releases?
Sign up for the HCUP
Mailing List to receive emailed information about
database releases, tools, and other HCUP product news. You also can check the HCUP-US News and Events page for
updates.
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- What are HCUP's nationwide databases?
HCUP's
nationwide databases provide estimates for hospital stays, emergency department
visits, or major ambulatory surgery encounters across the United States.
Consisting of the NIS, KID, NASS,
NRD, and NEDS,
the nationwide databases are built from the HCUP State
Databases. The databases contain information on all discharges or
encounters, regardless of expected payers. They can be used to create national
estimates of healthcare utilization, access, charges, quality, and outcomes. The
HCUP nationwide databases are available for purchase through the HCUP
Central Distributor. Statistics from select
databases are available on HCUPnet.
- Do I need to weight my nationwide database data?
Yes,
HCUP's nationwide databases need to be weighted to produce national estimates.
HCUP's free online tutorial called Producing
National HCUP Estimates provides
instruction on the process.
Please note that if you are using HCUPnet (HCUP's free, online query system), the weighting
already has been applied—the statistics produced are national estimates.
- When are the nationwide databases generally released, and what years of
data are available?
The NIS, NASS,
NEDS and NRD,
are released annually, approximately 18 to 22 months following the end of a
calendar year. Data years begin with 1988 for the NIS, 2016 for the NASS, 2006
for the NEDS, and 2010 for the NRD.
The KID is
released every 3 years, approximately 18 months following the end of a calendar
year. Data years begin with 1997 and run through 2012. The KID resumed release
in 2016.
Complete database availability and pricing information is
provided in the online HCUP Central Distributor Database Catalog. Database
releases also are noted on a monthly basis in the HCUP Database
and Product Releases Calendar.
- How much do the nationwide databases cost?
Complete
database availability and pricing information is included in the online HCUP
Central
Distributor Database Catalog. Cost varies
by year of data. Student pricing is available.
- Can I perform State-level analyses with the nationwide
databases?
The sampling methodology used to create the HCUP databases do not include
State as a stratifier; therefore, analysts cannot use the databases to generate
State-level estimates. Although the HCUP nationwide databases includes weights
to allow researchers to generate national estimates from the raw counts, no
weights are included for the calculation of State-level estimates.
For
information on State-specific inpatient stays, we recommend that you work with
the HCUP SID, SASD, or SEDD.
- Can they nationwide databases be linked together?
No.
Users are unable to link records across the nationwide databases.
- Are readmission analyses possible in the nationwide databases?
Readmission analyses are possible in only one nationwide database
– the NRD. For additional information, refer to the NRD-specific
section of
the FAQs.
- Is it possible to obtain information on intensive care unit (ICU)
services in the nationwide databases?
HCUP's nationwide
databases do not contain ICU information. Information on ICU services is
generally available via revenue codes, which HCUP's nationwide databases do not
contain. However, some of the HCUP State databases do contain this information
(HCUP data elements REVCDn
or
REVCODE). Information on
the
time in the ICU can be
identified by units associated with the revenue codes (HCUP data elements UNITn or UNITS).
- What resources are available to validate my estimates from the
nationwide databases?
There are several resources
available to validate your estimates from the nationwide databases. These
include:
- HCUP Summary Statistics: These include means on all numeric data
elements, frequency distributions, and univariates on continuous
variables. Summary statistics are provided by year and for each
database-specific file. For the Core File (or for the NASS, Encounter
File), both unweighted and weighted summary statistics are provided.
- HCUP Diagnosis and Procedure Frequency Tables: These tables are
available under the "Data Elements" section and include frequency
distributions for ICD-9-CM and ICD-10-CM/PCS codes (individually and by
grouped by clinical category including the Clinical Classification
Software [CCS] for ICD-9-CM, Clinical Classifications Software Refined
[CCSR] for ICD-10-CM/PCS, and diagnosis-related group [DRG]). For the
NASS, frequency distributions are available by Clinical Classifications
Software (CCS) for Services and Procedures category.
- HCUPnet: An online query system through which users can generate
statistics and information on inpatient and emergency department care as
well as population-based healthcare in counties. For the nationwide
databases, national statistics are provided overall as well as by
certain diagnosis and procedure classifications and for certain patient
and hospital characteristics. At this time, statistics are not available
in the ambulatory surgery setting.
- What are some best practices when working with the nationwide
databases?
To ensure researchers' appropriate use of the
nationwide databases, AHRQ has released a checklist for working with the NIS,
KID, NASS, NEDS, and NRD. The checklists are available for download on the
respective nationwide databases' documentation page on the HCUP-US website. The
checklists help researchers, manuscript peer reviewers, and journal editors
understand database design, strengths and limitations, and how they may have
changed over time. The checklist provides a step-by-step guide detailing key
elements to consider when evaluating studies using the HCUP nationwide
databases.
Additionally, the checklist refers to information resources
covering four key topics:
- Data use and acknowledgements
- Research design
- Data analysis
- Transition from ICD-9-CM to ICD-10-CM/PCS.
The checklist was derived from the JAMA article titled Adherence to Methodological Standards in Research Using
the National Inpatient Sample by
Khera
and colleagues.
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- What is the National Inpatient Sample (NIS)?
The National Inpatient Sample (NIS) is the largest
publicly available all-payer inpatient care database in the United States,
yielding national estimates of hospital inpatient stays. The NIS is a database
of hospital inpatient stays derived from billing data submitted by hospitals to
statewide data organizations across the U.S. These inpatient data include
clinical and resource use information typically available from discharge
abstracts. The NIS is sampled from the State Inpatient Databases (SID), which
include all inpatient data that are currently contributed to HCUP. The NIS is
available starting in data year 1988.
Additional information on the
NIS, including a description of data
elements and summary
statistics, can be found on the NIS
Database Documentation
page. The database can be purchased through the HCUP Central
Distributor, and statistics from the
NIS are available on HCUPnet.
- Can I perform multi-year or trend analysis using the NIS?
Yes, because the NIS spans more than 20 years of data, it is a good
tool for longitudinal analysis. However, the NIS has undergone various changes
over time, including changes to the sampling and weighting strategies used. The
NIS was significantly redesigned for database year 2012. For trend analysis
spanning 2012 and earlier years, revised discharge weights should be used to
make estimates comparable to the new 2012 NIS design.
To perform
multi-year or trends analysis using the NIS, AHRQ developed discharge trend weights for the 1993-2011
NIS, specifically the NIS Trend
Weight
Files. These weights were calculated in
the same way that weights were calculated for the redesigned 2012 NIS and are
designed to be used instead of the original NIS discharge weights for trend
analyses.
For trend analyses spanning 2012 and earlier NIS data, trend
weights should be used prior to 2012 data to make estimates comparable to the
new 2012 NIS design. Use the trend weight (TRENDWT) in place of the original
discharge weight (DISCWT) to create national estimates for trend analysis. For
2012 or later data, no trend weight is necessary and the discharge weight
supplied on the NIS files can be used. The trend weights are available for
download as ASCII files along with SAS®, Stata®, and SPSS® load
programs from the HCUP-US website.
These revised 1993-2011 trend
weights replace the earlier NIS trend weights that were developed for the
1988-1997 NIS following the 1998 NIS redesign. The report Using the
HCUP National Inpatient Sample to Estimate
Trends (PDF file, 1.0 MB) is available as a Methods Series report and includes
recommendations for trend analysis.
- Is it possible to track readmissions in the NIS?
You
cannot track readmissions using the NIS; however this can be done using the HCUP Nationwide
Readmissions Database (NRD), which 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. For
additional information, refer to the NRD section of the HCUP
FAQs.
- Can I perform State-level analyses with the NIS?
The
sampling methodology used to create the NIS does
not include State as a stratifier; therefore analysts cannot use the
database to generate State-level estimates. Although the NIS includes weights to
allow researchers to generate national estimates from the raw counts, no weights
are included for the calculation of State-level estimates.
For
information on State-specific inpatient stays, we recommend that you work with
the HCUP SID.
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- What is the Kids' Inpatient Database (KID)?
The KID is the largest publicly available all-payer
pediatric inpatient care database in the United States, yielding national
estimates of hospital inpatient stays for patients younger than 21 years of age.
Unweighted, it contains data from approximately three million pediatric
discharges each year that can be weighted to make national estimates for
pediatric care. Weighted, it estimates approximately six million hospital stays
for children. The KID is built from a sample of pediatric discharges from the SID.
The KID was released every three years from
1997 through 2012 and resumed release again in 2016.
Although the KID
is released every 3 years, the data include discharges for the single calendar
year (January to December). The KID's large sample size enables analyses of
common as well as rare conditions, such as congenital anomalies, and uncommon
treatments, such as organ transplantation. The KID includes charge information
on all patients, regardless of expected payer.
Additional information
on the KID, including a description of data
elements and summary
statistics, can be found on the KID
Database Documentation
page. The database can be purchased through the HCUP
Central Distributor, and
statistics from the KID are available on HCUPnet.
- How is the KID different from the NIS?
The KID is based on a stratified, random sample of
pediatric discharges (patients younger than 21 years of age) from the SID.
Ten percent of normal newborns and 80 percent of other
pediatric discharges (age 20 years or younger at admission) from 4,000 U.S.
community hospitals (defined as short-term, non-Federal, general and specialty
hospitals, excluding hospital units of other institutions), excluding
rehabilitation hospitals. A large sample size enables analyses of rare
conditions (e.g., congenital anomalies) as well as uncommon treatments (e.g.,
cardiac surgery).
The NIS does not oversample complicated newborns and
other (nonnewborn) pediatric discharges. The NIS, beginning data year 2012, is a
sample of discharges from all hospitals participating in HCUP. The NIS was
redesigned in 2012 to improve national estimates; the previous NIS contained all
discharge records from a sample of hospitals participating in HCUP.
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- What is the Nationwide Ambulatory Surgery Sample (NASS)?
The Nationwide Ambulatory Surgery Sample (NASS)
is
a
calendar-year, encounter-level
database of selected therapeutic ambulatory surgeries constructed from the
Healthcare Cost and Utilization Project (HCUP) State Ambulatory Surgery and
Services Databases (SASD).
The ambulatory surgeries selected for
inclusion in the NASS are therapeutic procedures which require the use of an
operating room, penetrate or break the skin, and involve regional anesthesia,
general anesthesia, or sedation to control pain. Procedures intended primarily
for diagnostic purposes are excluded. To be considered in-scope for the NASS,
ambulatory surgeries are also required to have a relatively high annual volume
or aggregate total facility charge. Examples include ambulatory surgeries such
as cataract surgery, cholecystectomy, appendectomy, gastric bypass,
hysterectomy, hernia repair, spinal fusion, and hip replacement.
Additional information on the NASS, including a description of data elements and summary statistics, can be
found on the NASS Database
Documentation page. The database can be purchased through the HCUP Central Distributor.
- What facilities are included in the NASS?
The NASS is restricted to hospital-owned facilities
in the HCUP State Ambulatory Surgery and Services
Databases (SASD) that perform in-scope ambulatory surgeries. The
designation of a facility as hospital-owned is specific to its financial
relationship with a hospital that provides inpatient care and is not related to
its physical location. Hospital-owned ambulatory surgery and other outpatient
care facilities may be contained within the hospital, physically attached to the
hospital, or located in a different geographic area. In addition to restricting
attention to hospital-owned facilities, facility selection criteria for the NASS
are (1) community nonrehabilitation hospital type and (2) a service type of
either general acute care or children's through data year 2018. Beginning data
year 2019, the NASS includes specialty hospitals such as surgical, cancer,
heart, and orthopedic facilities owned by community hospitals that performed
in-scope ambulatory surgeries. Additional restrictions imposed for the NASS
sampling frame are that the hospital (1) have no gross irregularities in
quarterly reporting volume, (2) submit data to the SASD in all four quarters of
the data year, and (3) not have an unusually low volume of encounters containing
an in-scope ambulatory surgery.
The HCUP SASD contain a number of
hospital-owned facilities performing in-scope ambulatory surgeries that are not
inpatient hospitals. In the NASS, these facilities are assigned the identifier
of the hospital owner. Stratification, sampling, weighting, and reporting are
performed using the hospital owner identifier and hospital characteristics.
Additional information about the NASS sampling frame can be found in
the Introduction the NASS document on the NASS
Database
Documentation page.
- Are ambulatory surgery centers (ASCs) included in the NASS?
The NASS is limited to in-scope ambulatory surgeries in hospital-owned
facilities. As such, ambulatory surgery centers (ASCs) that are not owned by a
hospital are not captured in the NASS.
- What procedures are included in the NASS?
The NASS is limited to encounters with at least one
in-scope ambulatory surgery on the record, performed at hospital-owned
facilities. In-scope ambulatory surgeries are defined as therapeutic procedures
that require the use of an operating room, penetrate or break the skin, and
involve regional anesthesia, general anesthesia, or sedation to control pain.
These surgeries are identified by CPT-coded procedures on the billing record,
and are categorized as narrow in the HCUP
Surgery Flag Software. They also belong to a subset of Clinical Classifications
Software (CCS) for Services and Procedures procedure groups with a
relatively high volume or aggregate total facility charge, and evidence of
reliable reporting from SASD hospitals. For additional information, see the
Introduction to the NASS document on the NASS
Database Documentation
page.
Note that although encounters are limited to those with
at least one in-scope ambulatory surgery on the record, the NASS Supplemental
File provides information on other surgical and nonsurgerical procedures
performed during these encounters.
- Can I use the NASS for longitudinal analysis?
The
NASS can be used for longitudinal analysis. However, users should be aware of
changes that have occurred to the NASS design over time. First, procedures
considered in-scope can change year to year. Second, the 2016-2018 NASS
undercounted certain emergent surgeries. Last, the NASS universe was modified to
include specialty hospitals in data year 2019. Additional information on these
changes is available in Section 4.8 of the NASS Introduction.
- Are all procedure codes included in the NASS?
The
NASS includes only CPT codes (Healthcare Common Procedure Coding System (HCPCS)
Level I codes). HCPCS Level II codes are excluded. Procedures that are
exclusively or predominantly reported on facility records using HCPCS Level II
codes will be underreported in the NASS. For this reason, CCS 45,
Percutaneous Transluminal Coronary Angioplasty (PTCA) was removed from
the NASS beginning in 2018.
- Would it be possible to see a list of CPT procedure codes that are
included in the NASS?
Our license agreement with the
American Medical Association (AMA) for using CPT codes also does not allow us to
distribute individual CPT codes. To obtain individual codes, it may be necessary
to license the CPT codes and obtain a CPT Codebook from the AMA or
work
with a medical records coder to develop a list.
However, the in-scope
ambulatory surgeries defined as selected invasive, therapeutic surgical
CPT-coded procedures also belong to a subset of CCS-Services and Procedures
procedure categories. For a detailed list of in-scope CCS procedure categories,
see the Introduction to the NASS on the NASS Database
Documentation page. You can then find the array of CPT and/or HCPCS
Level II codes used to assign CCS-Services and Procedures categories on the
CCS-Services and Procedures page of HCUP-US website.
- Does the NASS include information on ambulatory surgery charges and
costs?
The NASS includes the data element TOTCHG, which
provides the total charges for the entire ambulatory surgery encounter. The
total charge is not attributable to a single procedure. This information cannot
be determined. A Cost-to-Charge Ratio (CCR) File is not available for the NASS.
As a result, total charges for ambulatory surgery encounters in the NASS cannot
be converted to total facility costs.
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- What is the Nationwide Emergency Department Sample (NEDS)?
The NEDS is the largest publicly
available all-payer emergency department (ED) database in the United States,
yielding national estimates of ED visits. Unweighted, the NEDS contains
approximately 35.8 million records each year from about 1,000 hospital-owned
EDs. Weighted, it estimates approximately 145 million ED visits. The NEDS
contains discharges from more than 980 hospitals and approximates a 20 percent
stratified sample of U.S. hospital-owned EDs. It is constructed using records
from (1) the HCUP State Emergency Department Databases
(SEDD), which capture information on ED visits that do not result in an
admission (i.e., treat-and-release visits and transfers to another hospital),
and (2) the SID, which contain information on patients
initially seen in the ED and then admitted to the same hospital. The NEDS
includes ED charge information for approximately 96 percent of all U.S. ED
visits, regardless of expected payer.
Additional information on the
NEDS, including a description of data
elements and summary
statistics, can be found on the NEDS
Database Documentation
page. The database can be purchased through the HCUP
Central Distributor, and
statistics from the database are available on HCUPnet.
- Does the NEDS contain ICD-9-CM/ICD-10-CM/PCS procedure codes or CPT
codes?
The NEDS contains
both types of procedure codes; however, the type of code(s) depends on the
State, year, and the type of ED visit. For ED visits that do not result in
hospitalization, procedures may be reported as both ICD-9-CM and CPT, Fourth
Edition (CPT-4) procedure codes through data year 2015. Beginning data year
2016, procedures are reported as CPT codes only. These procedures are found in
the NEDS Supplemental ED File.
For ED visits resulting in
hospitalization, procedures are coded as ICD-9-CM codes through data year 2015
and ICD-10-PCS codes beginning data year 2016. These procedures are found in the
NEDS Supplemental Inpatient File.
- How do I differentiate between the two types of ED visits in the
NEDS?
The NEDS data element, HCUPFILE, can be
used to differentiate between ED visits that do not result in an admission
(HCUPFILE=SEDD) and ED visits that result in admission to the same hospital
(HCUPFILE=SID).
- Does the NEDS include information on ED charges and costs?
The NEDS includes two data elements with information on total charges
– TOTCHG_ED,
which provides the total charge of ED services, and TOTCHG_IP, which
provides the total charge for ED and inpatient services [ED admissions].
A Cost-to-Charge
Ratio (CCR) File is available for the NEDS beginning data year 2012.
These files were released in late 2021. Additional information is available at
https://www.hcup-us.ahrq.gov/db/ccr/ed-ccr/ed-ccr.jsp.
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- What is the Nationwide Readmissions Database (NRD)?
The NRD is the largest publicly available
all-payer readmissions database in the United States that can be used to examine
national estimates of readmissions. Unweighted, it contains approximately 18
million discharges each year. Weighted, it estimates approximately 35 million
discharges. The NRD is drawn from SID containing verified patient linkage
numbers that can be used to track a person across hospitals within a State.
Additional information on the NRD, including a description of data elements and summary statistics, can be found
on the NRD Database
Documentation page. The database can be purchased through the online HCUP Central Distributor, and select
statistics from the databases are available on HCUPnet.
- How are readmissions defined in the NRD?
The NRD is
designed to be flexible to various types of analyses of readmissions in the
United States for all patients, regardless of the expected payer for the
hospital stay. The NRD does not include any data elements that identify a
readmission. Instead, the criteria to determine the relationship between
multiple hospital admissions for an individual patient are left to the analyst
using the NRD. Outcomes of interest include national readmission rates, reasons
for returning to the hospital for care, and the hospital costs for discharges
with and without readmissions.
- Can I conduct a multi-year analysis with the NRD?
The
NRD can be used for analyzing trends in readmissions over times for specific
conditions or populations. However, we strongly recommend that users not combine
data years with the NRD. Users should consider each year of the NRD as a
separate sample. The patient linkage numbers (NRD_VisitLink)
do not track the same patient across years of the NRD. Additionally, the
hospital identifiers (HOSP_NRD)
do
not track the sample hospital across years
of the NRD. Each year of the NRD should be considered a separate sample.
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- What are the State databases?
HCUP's State databases
are a collection of all-payer datasets from participating States that can be
used to investigate State-specific and multi-state trends in healthcare
utilization, access, charges, quality, and outcomes. The HCUP State databases
consist of the State Inpatient Databases (SID), the State
Ambulatory Surgery and Services Databases (SASD), and
the State Emergency Department Databases (SEDD).
A
summary table shows the availability
of State-level data by database and year. Complete database availability and
pricing information is provided in the online HCUP
Central
Distributor Database Catalog.
Statistics from select States and settings are available on HCUPnet.
Please
review HCUPnet for a list of participating
States and their years of participation.
- Do I need to weight my State database data?
HCUP's
State databases do not need to be weighted. HCUP's State databases provide a
census (not an estimate) of inpatient stays, ambulatory surgery and other
outpatient service encounters, or emergency department encounters from each
participating HCUP Partner. For additional information, please review the HCUP Methods Series Report #2010-05:
Inferences With HCUP
State Databases Final Report (PDF file, 215 KB).
If a State is an HCUP Partner, why are its databases not available
through the HCUP Central Distributor or on HCUPnet?
HCUP Partners decide whether to distribute their
State-level, public-release databases through the HCUP
Central Distributor and whether to
distribute statistics on HCUPnet. As a result, data from any given State may be
available through one or both sources, and the years of participation can vary.
A summary table shows State
participation in the HCUP Central Distributor by database and year. Complete
database availability and pricing information is provided in the online HCUP
Central
Distributor Database Catalog. HCUPnet
provides a list of the available State statistics and years included in the
query system on the State statistics pathways.
If a State of interest
does not release its full dataset through the HCUP Central Distributor or
participate in HCUPnet, contact the HCUP Partner
directly for information about the availability of that State's data.
- When are the State databases generally released?
HCUP's State databases (SID, SASD, and SEDD) are released on a rolling basis—typically
beginning 6 to 9 months following the end of a calendar year.
A summary table shows
the availability of State-level data by database and year. Complete database
availability and pricing information is provided in the online HCUP
Central
Distributor Database Catalog. Recent
releases also are noted on a monthly basis in the HCUP Database and Product Releases
Calendar.
- What years of the State databases are available, and how much do they
cost?
The availability and cost of the State databases vary by State
and year. The earliest available years for the State databases are 1990 for the
SID, 1997 for the SASD, and 1999 for the SEDD; however, not all States provide
all data types and from every year.
Each HCUP
Partner sets its own pricing, and some charge by
applicant affiliation. A summary
table
shows the availability of State-level data
by database and year. Complete database availability and pricing information is
provided in the online HCUP Central Distributor Database Catalog.
Additionally, statistics and data tables from select SID and SEDD are available
on HCUPnet, HCUP's free, online query system.
Many
HCUP Partners participate in the HCUP Central
Distributor and HCUPnet; however not all do. To obtain State-level data
from a State that does not participate, contact the HCUP
Partner directly for information on the
availability of that State's data.
- Are readmission analyses possible with the State databases?
Yes, readmission analyses are possible with the SID, SASD, and SEDD for
those HCUP Partners that provide synthetic patient linkage numbers. AHRQ has
created the HCUP
Supplemental Variables for Revisit Analyses (i.e., revisit variables),
which are to be used exclusively with the SID, SASD, and SEDD. These variables
facilitate analyses that track patients across time and hospital settings for
state-level readmission analyses. To determine which State databases include the
revisit variables, refer to the User Guide
for the Supplemental Variables for Revisit Analyses, Appendix A.
- Is there a resource that provides information on the types of hospitals
and records found within the State databases?
We recommend
referring to the File Composition for the SID, SASD, and SEDD. The File
Composition for the SID, SASD, and SEDD include State-specific information on
the original data files provided by the HCUP Partner organizations for the
development of the HCUP State databases. This includes information about the
source of the original data files, the types of hospitals included in those
files, the records excluded during HCUP processing, and other pertinent
information to understand the composition of these files.
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- What are the State Inpatient Databases (SID)?
The SID are a set of all-payer inpatient care
databases from participating HCUP Partners that
capture hospital inpatient stays in a given State. They contain the universe of
inpatient discharge abstracts in participating States that are translated into a
uniform format to facilitate multi-state comparisons and analyses. The SID
contain a core set of clinical and nonclinical information on all patients,
regardless of expected payer.
Together, the SID encompass about 97
percent of all U.S. community hospital discharges.
The SID are the
building blocks of the NIS, the KID, the
NRD, and emergency department (ED) admissions in the NEDS. All SID include a core set of variables that commonly
are included on inpatient discharge abstracts, along with some State-specific
data elements.
Additional information on the SID, including a description of data
elements with participation by State and year and summary statistics for select States,
can be found on the SID Database
Documentation page. Select SID can be purchased through the HCUP Central Distributor, and
statistics from select States are available on HCUPnet.
- What is the difference between the SID and the NIS?
The SID and the National Inpatient
Sample (NIS) differ in design and availability of data elements. The SID
contain the universe of the inpatient discharge abstracts in participating
States. The NIS contains a sample of records from each SID that can be weighted
to represent national estimates. Additionally, the NIS contains fewer data
elements than the SID. The common data elements in the SID become the NIS core
data elements and are standardized.
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- What are the State Ambulatory Surgery and Services Databases
(SASD)?
The SASD include
encounter-level data for ambulatory surgeries and also may include data on
various types of outpatient services such as observation stays, lithotripsy,
radiation therapy, imaging, chemotherapy, and labor and delivery. The specific
types of ambulatory surgery and outpatient services included in each SASD vary
by State and data year. All SASD include data from hospital-owned ambulatory
surgery facilities. In addition, some States include data from facilities not
owned by a hospital. The designation of a facility as hospital-owned is specific
to its financial relationship with a hospital that provides inpatient care and
is not related to its physical location. Hospital-owned ambulatory surgery and
other outpatient care facilities may be contained within the hospital,
physically attached to the hospital, or located in a different geographic area.
Additional information on the SASD, including a description of data
elements with participation by State and year and summary statistics for select States,
can be found on the SASD Database
Documentation page. Select SASD can be purchased through the HCUP Central Distributor.
- What types of facilities are included in the SASD?
All
SASD include data from hospital-owned ambulatory
surgery facilities. In addition, some States include data from nonhospital-owned
facilities. The designation of a facility as hospital-owned is specific to its
financial relationship with a hospital that provides inpatient care is not
related to its physical location. Hospital-owned ambulatory surgery and other
outpatient care facilities may be contained within the hospital, physically
attached to the hospital, or located in a different geographic area. The
designation as hospital-owned means that HCUP can identify that the hospital is
billing for this service. Refer to the Introduction to the
SASD for a list of States that provide HCUP with information from
hospital-owned facilities. A complete list of the types of facilities included
in the SASD can be found on the SASD
File Composition page.
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- What are the State Emergency Department Databases (SEDD)?
The SEDD are a set of all-payer
emergency department (ED) databases from participating HCUP
Partners
that capture discharge information on
all ED encounters that do not result in an admission to the same
facility. They include a universe of abstracts from hospital-owned ED encounters
from community hospitals. Composition and completeness of the variables in the
file may vary from State to State. The SEDD contain a core set of clinical and
nonclinical information on all patients, regardless of expected payer.
Additional information on the SEDD, including a description of data
elements with participation by State and year and summary statistics for select States,
can be found on the SEDD Database
Documentation page. Select SEDD can be purchased through the HCUP Central Distributor, and
statistics from select States are available on HCUPnet.
- Do the SEDD include all ED encounters—both those in which the
patient was admitted and those in which the patient was treated and
released?
No. The SEDD
provide encounter-level information for ED encounters that do not
result in an admission to the same facility (i.e., patients in the SEDD were
treated and released). Records for inpatient stays that began in the ED are
found in the SID. These records can be identified by the data
element HCUP_ED. Both the
SEDD and SID are needed to analyze all
ED encounters in a State.
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- How can I access data or statistics from HCUP?
The
HCUP databases are available for purchase online through the HCUP Central Distributor. All
purchasers must complete the online HCUP Data Use
Agreement (DUA) Training and create an HCUP Central Distributor user
account in order to submit an application to purchase HCUP data. Please see HCUP Central Distributor FAQs for additional
information.
Statistics and data tables from HCUP's nationwide and
select State databases can be obtained from HCUPnet, a
free, online query system. Statistics and data tables on select topics are also
available through HCUP Fast
Stats.
HCUP is a voluntary partnership between the Federal
government and State data organizations (HCUP
Partners). Each Partner determines how its data are used in HCUP; thus,
not all States participate in the HCUP Central Distributor, HCUPnet,
and/or
Fast Stats.
- Can I obtain a customized dataset or access additional elements that are
not included in the standard HCUP databases?
HCUP does not
offer customized datasets—the data are offered as standard databases. No
elements beyond those that already are included in the standard databases are
available to the public.
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How do I contact the HCUP Central Distributor?
You may contact the HCUP Central Distributor Team by emailing HCUP-RequestData@ahrq.gov (include your
order number in the subject line, if applicable).
-
Where can I learn more information
about the HCUP Central Distributor?
The HCUP Central Distributor User Guide [PDF, 326 KB]
provides detailed instructions on how to purchase, protect, use, re-use and
share the HCUP data.
-
What training is required to use HCUP databases?
Complete the HCUP Data
Use Agreement (DUA) training course. This training is
required of all purchasers and all individuals with access
to HCUP data and takes approximately 15 minutes to complete. Make note of
your certification code and completion date for proof of training, which is
required when placing an order for HCUP data or submitting HCUP Data Use
Agreements.
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What types of payment are accepted in the HCUP Central Distributor Online
Reporting
System?
Currently, the online system is only accepting credit card
purchases. Future versions will include ACH payment. If you need to purchase
the data via purchase order or wire transfer, please contact the HCUP
Central Distributor Team at HCUP-RequestData@ahrq.gov.
-
I am interested in purchasing HCUP State databases. When will I be able to use
the
Central Distributor Online Reporting System to submit my order?
We expect that HCUP State databases will be available for purchase through the HCUP Central Distributor Online Reporting System
by
late Fall / early Winter 2023. We will put an announcement out through the HCUP
Mailing List. We apologize for the inconvenience.
-
I am a student, are there any discounts to purchase data?
Part-time and full-time students, including medical residents, currently
enrolled in a degree-seeking program at an institution of higher learning at
any stage in their training are eligible for the student prices published on
HCUP data page. Data purchased as students must be used exclusively for
student projects . Please see the HCUP Central Distributor User Guide [PDF, 326 KB ]
for more details.
-
How long will it take for me to receive my data?
HCUP Nationwide databases purchased through the HCUP
Central Distributor Online Reporting System are available for download after
payment
confirmation, typically within hours but may take 1-2 days in the system. Purchases of
HCUP
State databases currently take 2-3 weeks to be fulfilled.
-
I am having trouble downloading and unzipping the data that I received. Where can
I
get help?
Databases will not be available for download until payment is received and processed.
The length of time to download the Nationwide databases can vary. Download
performance depends on several highly variable factors including the following:
1) internet connection speed and bandwidth,
2) global and regional internet traffic demand at the time of your download, and
3) other users demand on your network or internet service provider (ISP) resources at
the
time of your download.
HCUP databases use a process that compresses and encrypts the files into a
password-protected file (in either zip or exe format) which only can be
extracted or unzipped using a third-party zip utility such as
SecureZIP®, 7-zip, ZIP Reader, WinZip™, SecureZIP®for Mac,
StuffIt Expander®, or Keka. Attempts to extract files using the built-in
zip utilities in Windows® (Windows Explorer) or Mac (Archive Utility)
will produce an error message warning of incorrect password and/or corrupted
file or folder errors.
Note for Nationwide databases: There are two layers of compression for the
database. The outer layer compresses all content of the database related
files into one package, which is what you download from the website. This
package includes uncompressed documents like user guide and the database
files that are compressed.
Please refer to the HCUP Central Distributor User Guide to troubleshoot the
issue. If the information provided in the Guide does not help, please
contact the HCUP Central Distributor Team at HCUP-RequestData@ahrq.gov.
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I am an existing user, how do I access my account?
The new HCUP Central Distributor Online
Reporting System is accessed through https://cdors.ahrq.gov/. In most
cases, your Username is your email address. If your email is not your
Username, please click on Forgot Password or Username, type in the email
address you used previously in the Request a username recovery box, and you
will receive an email with your Username. Once you have established your
Username, you will need to reset your password. Please confirm and/or update
your User information in the system. All previous HCUP Central Distributor
orders should be visible to you in the system.
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I am having trouble with my password and accessing my account on HCUP Central
Distributor Online Reporting System. Where can I get help?
Remember passwords are case sensitive. If you have forgotten your password,
please click “Forgot password or username?” at the boottom of
the sign-in page to reset your password. If you still need help, please
contact the HCUP Central Distributor Team at HCUP-RequestData@ahrq.gov,
and one of the developers of the system will be able to assist.
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When will the website be fully available?
We expect the HCUP Central Distributor Online Reporting
System to be fully functional late Fall / early
Winter 2023. The first phase allowing Nationwide data purchases with a
credit card is currently available. Additional updates will include, but are
not limited to, the ability to purchase via ACH, ability to purchase HCUP
State databases, submission of collaborator DUAs, submission of state data
re-use requests, and submission of custodian transfer applications. We
appreciate your patience in waiting for a secure online system.
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I submitted an email
application,
what is the status of my application?
We are slowly working our way through all orders placed via email. Please
contact the HCUP Central Distributor Team at HCUP-RequestData@ahrq.gov
regarding the status of your application. Please include the order number in
the subject line to facilitate a response.
-
I submitted an email
application for
HCUP Nationwide databases; do I need to resubmit my application in the
online system?
Yes, you will need to resubmit your Nationwide database application. The
system does not allow AHRQ to pre-populate orders. If you previously put in
an order via email, we have a copy of your original order, and can provide
it to you.
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I submitted an email
application for
HCUP State databases; what is the status of my application?
For State database applications, we will continue to process the orders
manually. The process will be quite slow due to the volume of responses, and
we appreciate your patience.
-
I received an invoice for my data purchase application, are you still accepting
payment?
If you received an invoice for HCUP Nationwide databases, please re-submit
your database application on the HCUP
Central Distributor Online Reporting System to facilitate getting
the data via a download link. You will be able to pay via credit card. If
you would like to use another method of payment for HCUP Nationwide
database(s), please email the HCUP Central Distributor Team at HCUP-RequestData@ahrq.gov
and let us know your preference (include your application number from the
online system in the subject line).
For State database orders, we are still accepting payment via ACH, wire
transfer or purchase order. Credit card purchase of HCUP State database
orders is not currently available. Please email the HCUP Central Distributor
Team at HCUP-RequestData@ahrq.gov if
you have questions (include your application number from the online system
in the subject line).
-
Is the HCUP Central Distributor still accepting applications via email?
Yes. The HCUP Central Distributor is accepting email applications for the
following types of applications:
- Additional Data Use Agreements for collaborators
- Data Re-Use Requests for State-level data
- Transfer of Custodianship of the data
If you want to purchase HCUP State databases, we kindly ask that you wait for
it to be available through the online system in late Fall / early Winter
2023, if at all possible. Please contact the HCUP Central Distributor Team
with questions: HCUP-RequestData@ahrq.gov
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- What are the HCUP software tools?
The HCUP software
tools can be applied to HCUP and other administrative databases to create new
data elements from existing data, thereby enhancing a researcher's ability to
conduct analyses. The HCUP software tools are available for download from the
HCUP-US website and are free of charge. Additional information is available in
the Research Tools section of
the HCUP-US website.
- How often are the HCUP software tools updated? The HCUP
software tools are updated annually to coincide with either fiscal year updates
to the ICD-10-CM/PCS coding system or calendar year updates for CPT and HCPCS
Level II codes. For this reason, it is always advisable to use the most recent
version of the tool.
The HCUP software tools for ICD-9-CM are no longer
updated. These tools should be used only for administrative data before October
2015.
- What is the Clinical Classifications Software Refined (CCSR) for
ICD-10-CM/PCS?
The CCSR is a diagnosis and procedure
categorization scheme that was developed by AHRQ. It aggregates ICD-10-CM/PCS
diagnosis and procedures codes into clinically meaningful categories.
- The CCSR for
ICD-10-CM diagnoses groups diagnosis codes into more than 530
clinical categories. It balances the retention of the clinical concepts
included in the CCS categories under ICD-9-CM and the specificity of
ICD-10-CM diagnoses by creating new clinical categories. The CCSR for
ICD-10-CM diagnoses is intended to be used analytically to examine
patterns of healthcare in terms of cost, utilization, and outcomes; rank
utilization by diagnoses; and risk-adjust by clinical condition.
- The CCSR for
ICD-10-PCS procedures groups procedure codes into more than 320
clinical categories. It capitalizes on the taxonomy and specificity of
the ICD-10-PCS coding scheme and, where possible, retains the same
surgical concepts from prior CCS versions. The CCSR for ICD-10-PCS
procedures is intended to be used analytically to examine patterns of
healthcare in terms of cost, utilization, and outcomes, in addition to
ranking utilization by procedures.
The CCSR replaces the beta version of the CCS for ICD-10-CM/PCS. The
beta version of the CCS of ICD-10-CM/PCS codes will not be updated for newer
codes (ICD-10-CM codes after October 2019 and ICD-10-PCS codes after October
2020). It is recommended that the beta version of the tool no longer be used.
- The assignment of CCSR categories in the CCSR for ICD-10-CM diagnoses
tool is not mutually exclusive. How do I account for this if my analysis is
limited to reporting by the principal diagnosis (DX1)?
For
some applications, a mutually exclusive categorization scheme is needed. For
example, performing rank utilization by the principal (or first-listed)
diagnosis. To facilitate such analyses, the CCSR tool includes the assignment of
a default CCSR category for the principal diagnosis in inpatient data and the
first-listed diagnosis in outpatient data. Correct application would be
dependent upon your dataset's setting of care. Additional information is
available in the User Guide for the CCSR for ICD-10-CM diagnoses.
- I am having problems applying the CCSR for ICD-10-CM diagnoses to my
administrative data. What could be the issue(s)?
Please
note the input dataset must contain certain elements that are coded in specific
ways. These data elements are required for the assignment of the CCSR for
ICD-10-CM categories:
- A unique record identifier (KEY in most HCUP databases)
- An array of ICD-10-CM diagnosis codes, decimals removed; user specifies
the length of the array
- For an administrative database that includes a mixture of inpatient and
outpatient records, there must be a data element with values that
distinguishes between these records [this ensures the appropriate
default CCSR is applied as in some cases, the assignment differs between
the two data types].
Additionally, the following are common mistakes that are made by
users of the CCSR for ICD-10-CM diagnoses tool when applying to HCUP or other
administrative databases:
- Data element names in the input data file do not match the data element
names in the SAS program
- Diagnosis codes include decimals
- There is no indication that the input data file was specific to
inpatient, outpatient or both inpatient and outpatient data in the SAS
Mapping Program (this is a required macro).
If you continue to encounter issues, we recommend consulting the User Guide for
the
CCSR for ICD-10-CM diagnoses as well
as the HCUP Software Tools tutorial, both of which are helpful in identifying
what information needs to be modified by the user in the tool's SAS Mapping
program.
- What is the Elixhauser Comorbidity Software Refined for
ICD-10-CM?
The Elixhauser
Comorbidity Software Refined for ICD-10-CM is
a product developed by AHRQ that identifies different pre-existing conditions
based on secondary diagnoses (i.e., comorbidities) listed on hospital
administrative data. This tool creates 38 variables that identify comorbidities
(e.g., heart failure, HIV) in hospital discharge records. In health services
research, it is often important to control for comorbidities that co-exist at
the time of the hospitalization or outpatient encounter, impact resource
allocation (e.g., length of stay or charges), and possibly affect outcomes, such
as in-hospital mortality.
The Elixhauser Comorbidity Software was
originally developed using ICD-9-CM diagnosis codes. The software was translated
into ICD-10-CM prior to the availability of ICD-10-CM-coded data and released as
a beta version. Once ICD-10-CM-coded data became available, the beta version of
the Elixhauser Comorbidity Software was evaluated by clinical experts. The
recommended modifications (implemented in v2021.1) transition the software tool
out of its beta status and into the Elixhauser Comorbidity Software Refined for
ICD-10-CM. It is recommended that the beta version of the tool no longer be
used.
- Can the Elixhauser Comorbidity Software Refined for ICD-10-CM be applied
to both inpatient and outpatient data? The ICD-9-CM version of this tool was
only applicable to inpatient data.
Yes, the Elixhauser
Comorbidity Software Refined for ICD-10-CM can be applied to both inpatient and
outpatient data, however, users should be mindful that the refinement process
was focused on adult, nonmaternal inpatient stays.
If the tool is being
used with outpatient data, some measures like diabetes and obesity may be
underreported because of ICD-10-CM coding guidelines for reporting secondary
diagnoses on outpatient data, which state: "Secondary diagnoses should
indicate additional conditions that affect patient care in terms of requiring
clinical evaluation, therapeutic treatment, diagnostic procedures, extended
length of stay, or increased nursing care and/or monitoring."2
2 ICD-10-CM Official Guidelines for Coding and Reporting FY
2022 (https://www.cms.gov/files/document/fy-2022-icd-10-cm-coding-guidelines.pdf).
- I noticed that the Elixhauser Comorbidity Software Refined for ICD-10-CM
is applied to all HCUP nationwide databases beginning data year 2019 except
the KID. Why is that?
As noted in the above FAQ, the
refinement process for the Elixhauser Comorbidity Software Refined for ICD-10-CM
focused on adult, nonmaternal inpatient stays. Additional work needs to be done
to understand using the comorbidity measures for studying pediatric
hospitalizations before it can be included on the KID. Some measures like
dementia may not apply to the pediatric population and other comorbidities of
possible interest (e.g., sickle-cell anemia) are not included.
- I am getting a value of 0 for all comorbidity measures in the output
dataset. What could be wrong?
Please note the input
dataset must contain certain elements that are coded in specific ways. These
data elements are required for the assignment of the comorbidity measures and
are identified in the above FAQ.
Additionally, the following are common
mistakes that are made by users of the Elixhauser Comorbidity Software Refined
for ICD-10-CM when applying to HCUP or other administrative databases:
- Data element names in the input data file do not match the data element
names in the SAS Analysis Program
- Diagnosis codes include decimals
- Input data file only includes a principal diagnosis, no secondary
diagnoses (comorbidity measures are only assigned to secondary
diagnoses)
- Indicators that diagnoses are POA are not coded as expected by the SAS
Mapping Program (e.g., "Y", "W", "N", "U").
If you continue to encounter issues, we recommend consulting the User Guide
for
the Elixhauser Comorbidity Software Refined
for ICD-10-CM as well as the HCUP Software Tools tutorial, both of which
are helpful in identifying what information needs to be modified by the user in
the tool's SAS Mapping program.
- What are the Elixhauser Comorbidity Indices Refined for
ICD-10-CM?
The Elixhauser Comorbidity Indices were
originally developed using ICD-9-CM diagnosis codes and adult, nonmaternal
inpatient discharge data.3 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.
The Elixhauser
Comorbidity Indices Refined for ICD-10-CM is
designed to predict two frequently reported health outcomes:
- Risk of in-hospital mortality
- Risk of 30-day, all-cause readmission
Each index is a separate composite score based on the 38 individual
comorbidity measures. Using the indices can be preferable to the individual
measures because they account for interaction between comorbidities and reduce
the necessary degrees of freedom required for estimation-especially helpful when
working with small sample sizes.
3 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 Jul;55(7):698-705.
- Can I assign the indices to my administrative data if only a subset of
the comorbidity measures is assigned? My administrative data do not include
indicators that a diagnosis was POA, which is required for 18 of the
comorbidity measures.
The Elixhauser Comorbidity Indices
Refined for ICD-10-CM depend on all 38 Elixhauser Comorbidity Software Refined
for ICD-10-CM measures being coded in the data. Therefore, your data must
include indicators that a diagnosis was POA.
- How do I interpret the comorbidity measures with a negative weight? What
about a weight of 0?
The comorbidity measures are assigned
a weight designed to capture the relative risk of in-hospital mortality or a
30-day all-cause readmission of each comorbidity in relation to the other
comorbidity measures. For example, a comorbidity with a weight of 5 has five
times the weight of a comorbidity with a weight of 1. Some comorbidity weights
carry a negative sign, reflecting a protective relationship with in-hospital
mortality or readmissions in the context of the other comorbidities. A weight of
zero indicates that the comorbidity measure does not significantly contribute
positively or negatively to the risk of in-hospital mortality or 30-day
all-cause readmission. It is included in the calculation of the index for
completeness.
- What is the Chronic Condition Indicator Refined (CCIR) for
ICD-10-CM?
The CCIR
for ICD-10-CM is a tool developed by the AHRQ that facilitates health
services research by allowing the researcher to readily identify a diagnosis as
indicating a chronic condition. The CCIR tool identifies three types of
conditions:
- Chronic: Examples include malignant cancer, diabetes, obesity and
hypertension
- Not Chronic: Examples include benign neoplasm, postprocedural
complications, pregnancy, and an initial encounter for an injury
- Codes where no determination was made on the identification of a chronic
condition (value 9). Examples include external cause of morbidity codes
and codes for factors influencing health status and contact with health
services.
The CCIR for ICD-10-CM replaces the beta version of the CCI for
ICD-10-CM. It is recommended that the beta version of the tool no longer be
used.
- What is the definition of a chronic condition in the CCIR for ICD-10-CM
tool?
The definition of a chronic condition is dependent
on duration (a condition lasting 12 months of longer) and its effect on the
patient based one or both of the following criteria:
- The condition results in the need for ongoing intervention with medical
products, treatment, services, and special equipment
- The condition places limitations on self-care, independent living, and
social interactions.4
A diagnosis code that describes a chronic condition fitting the above
definition is considered chronic, even if the code description includes
information on an acute exacerbation. For example, the codes for Sickle-cell
disease without crisis and Sickle-cell disease with acute chest syndrome are
both considered chronic.
Consistent with the ICD-9-CM version, any
diagnosis that indicates an amputation, a transplant, or a malignant cancer is
considered a chronic condition. Most congenital codes are chronic.
4 Perrin EC, Newacheck P, Pless IB, Drotar D, Gortmaker SL, Leventhal
J, Perrin JM, Stein RE, Walker DK, Weitzman M. Issues involved in the definition
and classification of chronic health conditions. Pediatrics. 1993
Apr;91(4):787-93.
- Does the CCIR for ICD-10-CM value, Not Chronic, indicate an acute
condition?
The designation of not chronic is not
synonymous with acute. For example, diagnoses indicating pregnancy, or a benign
neoplasm are not chronic, but also not an acute condition requiring immediate
short-term treatment.
- How should the CCIR for ICD-10-CM be used for an analysis that counts
chronic conditions?
The CCIR for ICD-10-CM tool assigns a
value to every diagnosis code and as such identifies any diagnosis on a record
that is chronic. In some cases, more than one diagnosis code on a record may
indicate the same chronic condition. In fact, ICD-10-CM coding guidelines
require that two diagnosis codes be reported for certain conditions. For
example, the record for a patient with hypertensive chronic kidney disease will
contain the hypertensive chronic kidney disease code as well as a code
indicating the stage of chronic kidney disease. Both codes will have a CCIR
value of chronic. But this does not mean that the patient has two distinct
chronic conditions.
To address this, the recommendation is to use the
CCIR tool in combination with the CCSR for ICD-10-CM diagnoses. It is possible
to use the CCSR diagnosis categories to help identify when multiple diagnoses
indicate a similar chronic condition.
- What are the Procedure Classes Refined for ICD-10-PCS?
The Procedure
Classes Refined for ICD-10-PCS facilitates
health services research by allowing the researcher to readily determine (1)
whether a procedure is diagnostic or therapeutic and (2) whether a procedure is
expected to be performed in an operating room. The Procedure Classes Refined for
ICD-10-PCS assign all ICD-10-PCS procedure codes to one of four categories:
- Minor Diagnostic: Nonoperating room procedures that are diagnostic
(e.g., B244ZZZ, Ultrasonography of Right Heart)
- Minor Therapeutic: Nonoperating room procedures that are therapeutic
(e.g., 02HQ33Z, Insertion of Infusion Device into Right Pulmonary
Artery, Percutaneous Approach)
- Major Diagnostic: Procedures that are considered operating room
procedures that are performed for diagnostic reasons (e.g., 02BV0ZX,
Excision of Superior Vena Cava, Open Approach, Diagnostic)
- Major Therapeutic: Procedures that are considered operating room
procedures that are performed for therapeutic reasons (e.g., 0210093,
Bypass Coronary Artery, One Site from Coronary Artery with Autologous
Venous Tissue, Open Approach).
The Procedure Classes Refined replaces the beta version of the tool.
The beta version of the Procedure Classes will not be updated for newer codes
and it is recommended that it no longer be used.
- What is the Clinical Classifications Software (CCS) for Services and
Procedures?
The CCS for
Services and Procedures provides a method for classifying CPT and HCPCS
Level II codes into more than 240 clinically meaningful procedure categories.
The procedure categories are similar to the Clinical Classifications Software
(CCS) for ICD-9-CM procedure classification with the addition of specific
categories unique to the professional service and supply codes in CPT and HCPCS
Level II codes.
- Will the CCS-Services and Procedures be updated to align with the new
CCSR for ICD-10-CM diagnoses categories?
While we
understand that there is a need for this, especially for analyses that examine
procedure trends within the inpatient and outpatient settings, we do yet have a
plan to update the CCS-Services and Procedures categories to align with the CCSR
for ICD-10-CM diagnoses.
- What is the Surgery Flags Software for Services and Procedures?
The Surgery Flags Software for Services and Procedures
identifies a subset of CPT codes as surgical procedures:
- CPT Category I, Surgery:10004-69990
- CPT Category I, Radiology procedures (added in v2019.2): 70010-79999
- CPT Category I, Medicine services and procedures (added in v2019.2):
90281-99756, excluding the evaluation and management codes in the range
99201-99499
- CPT Category III Codes, Temporary codes for emerging or experimental
services, technology, or procedures (added v2018): 0042T-0593T
Excluded are all other ranges of CPT Category I codes (i.e., codes
specific to anesthesia, pathology and laboratory procedures, evaluation and
management services, laboratory analyses, multianalyte assay), any CPT Category
II codes, and all HCPCS Level II codes.
CPT codes in the specified
ranges are classified as one of three categories:
- A narrowly defined surgery (Narrow) that is usually a major therapeutic
procedure
- A more broadly defined surgery (Broad) that includes major diagnostic
and invasive minor therapeutic procedures
- Neither a narrowly nor broadly defined surgery (Neither)
- Are the CCS- and Surgery Flags-Services and Procedures tools valid for
all calendar years?
Beginning with the v2020.1 release of
the CCS-Services and Procedures and Surgery Flags-Services and Procedures, the
tools are based on CPT and HCPCS Level II codes valid as of the calendar year.
For users interested in applying the CCS-Services and Procedures and
Surgery Flags-Services and Procedures to CPT and HCPCS Level II codes valid
before January 1, 2020, older versions are archived for download on the HCUP-US
website at www.hcup-us.ahrq.gov/toolssoftware/ccs_svcsproc/ccssvcproc.jsp
and www.hcup-us.ahrq.gov/toolssoftware/surgeryflags_svcproc/surgeryflagssvc_proc.jsp.
- Is a reference file available for the CCS-and Surgery Flags-Services and
Procedures tools that lists the CPT or HCPCS Level II codes mapped into
respective CCS categories or surgery flag values?
While a
reference file is available for both tools, HCUP does not provide lists of
individual CPT or HCPCS Level II codes for either of these tools. The
CCS-Services and Procedures category and surgery flag mappings are provided as
code ranges that can be recognized by a statistical package like SAS or SPSS.
Descriptions for the code ranges are not provided. Our license agreement with
the AMA for using CPT codes also does not allow us to distribute individual
codes. To obtain individual codes, it may be necessary to license the CPT codes
and obtain a CPT Codebook from the AMA or work
with a medical records coder to develop a list.
- What are the HCUP software tools for ICD-9-CM?
The
HCUP software tools for ICD-9-CM include the following:
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- What are the HCUP Supplemental Files?
The HCUP
Supplemental Files are available for use with the HCUP databases to enhance a
researcher's ability to conduct analyses. These files are not applicable to
other administrative databases. Most of these files are available for download
from the HCUP-US website. Others may be ordered through the online HCUP Central
Distributor. All are available free of charge.
- What are the American Hospital Association (AHA) Linkage Files?
The HCUP
AHA Linkage Files are used to supplement the HCUP SID, SASD, and SEDD
with hospital-level information from the AHA Annual Survey Databases. The AHA
Annual Survey Databases are purchased separately from the AHA .
The HCUP
AHA Linkage Files allow for richer empirical analysis especially where hospital
characteristics may be important factors. They include the hospital identifier
used on the AHA Annual Survey Databases and the HCUP hospital identifier for
those HCUP Partner States that release hospital identifiers.
The HCUP
AHA Linkage Files are available for download from HCUP-US for the HCUP Central
Distributor SID, SASD, and SEDD beginning with 2006 data. The AHA Linkage Files
are updated annually. The HCUP AHA Linkage Files prior to 2006 were included on
the data CD-ROMs provided with purchase. Please note that not all HCUP Partner
States release hospital identifiers.
- How do I link the HCUP AHA Linkage Files with the HCUP SID, SASD, and
SEDD?
The HCUP AHA Linkage Files can be linked to the HCUP
SID, SASD, and SEDD Core Files using the HCUP data source hospital
identification number (data element DSHOSPID). Then, subsequently, users can
merge the data elements of interest from the AHA Annual Survey Databases to the
HCUP AHA Linkage Files using the AHA hospital identifier (data element AHAID).
- I recently received the Iowa, Minnesota, and Nebraska AHA Linkage Files
through special request from the HCUP Central Distributor. How do I link the
AHA Linkage Files for these three States to the corresponding SID, SASD, and
SEDD?
The Iowa, Minnesota, and Nebraska AHA Linkage Files
are provided by special request to certain approved purchasers whose use of the
data is consistent with the Partner organization's requirements. These special
request files are constructed using discharge records rather than hospitals as
the unit, and there is a match for every record in the data file. For these
three States, the AHA Linkage Files can be linked directly to the SID, SASD, and
SEDD Core Files using the HCUP record identifier (data element KEY).
- What are the Cost-to-Charge Ratio Files (CCR Files)?
The CCR Files are
linkable files developed by AHRQ that enable the conversion of total charges
(defined as the amount a hospital billed for services) into how much the
hospital services actually cost. Cost information was obtained from the hospital
accounting reports in the Healthcare Cost Report Information System (HCRIS)
files collected by the Centers for Medicare & Medicaid Services (CMS). Some
imputations for missing values were necessary. The CCR Files are hospital-level
files designed to supplement the data elements in HCUP inpatient and emergency
department databases.
Each CCR File contains hospital-specific
cost-to-charge ratios based on all-payer inpatient or emergency department cost
for nearly every hospital in the corresponding NIS, KID, NRD, SID, SEDD, and
NEDS. The CCR Files are updated annually for the SID, NIS, and NRD and every 3
years for the KID beginning with 2001 data and the SEDD and NEDS beginning with
2012 data.
- How do I link the CCR Files to the HCUP databases?
The
CCR Files can be linked to records in the HCUP databases using the HCUP hospital
identification number, which is a unique hospital number exclusive to the HCUP
data. The name of the data element representing the hospital identification
number varies by database and data year.
For nationwide database CCR
Files (CCR-NIS, CCR-KID, CCR-NRD, and CCR-NEDS), the CCR records can be merged
directly with the records in the corresponding database using the database's
hospital identification number (HOSP_NIS, HOSP_KID, HOSP_NRD, and HOSP_ED,
respectively).
For States that release an HCUP AHA Linkage File,
linkage between the CCR File and the SID or SEDD is achieved in two steps. First
by linking records from the CCR for SID or SEDD file to the HCUP AHA Linkage
File by the data element HOSPID. For Iowa, Minnesota, and Nebraska, this linkage
is achieved using the data element KEY. Second, by linking the resulting file to
the SID or SEDD by State (data element Z013) and data element DSHOSPID.
For States that do not release an HCUP AHA Linkage File, HOSPID is included
directly on their SID or SEDD file. For these States, the data elements from the
CCR File can be merged onto the SID or SEDD by HOSPID.
- What are the Supplemental Variables for Revisit Analyses?
The HCUP
Supplemental Variables for Revisit Analyses, or revisit variables, are
additional variables that were developed by AHRQ. They facilitate analyses to
track patients across time and hospital settings exclusively in the SID, SASD,
and SEDD while adhering to strict privacy guidelines.
There are two
HCUP supplemental variables
- Synthetic person-level identifiers that have been verified against the
patient's date of birth and gender and examined for completeness (HCUP
variable VisitLink).
- A timing variable that can be used to determine the days between
hospital events for an individual without the use of actual dates
(admission, discharge or birth) (HCUP variable DaysToEvent).
Beginning with 2009 data, the Revisit Variables are included in the
Core file of the SID, SASD, and SEDD databases for select States that are
purchased through the HCUP Central Distributor. For 2003-2008 data, the Revisit
Variables are provided free of charge as a separate file with the applicable
state databases.
- Which States, databases, and years have revisit variables?
Appendix A of the HCUP
Supplemental Variables for Revisit Analyses User
Guide provides a detailed list of which States, years, and types of data
are available.
- How do I determine if I can follow patients over time in a
State?
It is possible that over time, some HCUP Partners
will modify the encryption routines used for their synthetic patient linkage
numbers. If this occurs, there will be a one-time disruption in the ability to
track a patient over time. For more information, review Appendix C of the HCUP Supplemental
Variables for Revisit Analyses User Guide to determine the consistency
of visitlink over time.
- How do I determine if I can follow patients across settings of care in a
State?
For more information, review Appendix D of the HCUP Supplemental
Variables for Revisit Analyses User Guide to determine the consistency
of visitlink between the SID and SASD/SEDD within a data year.
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- What is HCUPnet?
HCUPnet is a
free, online query system that provides statistics and data tables based on HCUP
data. Its easy, step-by-step process allows users to explore many healthcare
topics relating to hospital inpatient services and emergency department
settings. Users also may generate tables and graphs on national and regional
statistics including hospital readmissions and trends on hospital and emergency
department use in the United States. In addition, State-specific statistics,
including information at the county-level, are available for States that have
agreed to participate in HCUPnet.
HCUPnet can access
statistics from all HCUP databases: the NIS, the KID, the NRD, the NEDS,
selected SID and selected SEDD.
Information in HCUPnet
includes:
- Diagnosis and procedure classifications (e.g., diagnosis-related groups
[MS-DRGs], CCSR categories, major diagnostic categories [MDCs])
- Patient demographic characteristics
- Hospital characteristics
- Expected payer
- Discharge status
- Length of stay
Additional information provided by HCUPnet includes
the following:
- In-hospital mortality for diagnosis and procedure classifications
- Trends in inpatient and outpatient access, charges, and outcomes
- Utilization by special populations
- Most common conditions and procedures
- Variations in medical practice
- Quality of care and patient safety
- Differences in outcomes between hospital type
- National estimates of hospital readmissions
- Online z-test calculator to test statistical significance of differences
between two weighted counts, means, or percentages
- Validation of results obtained from the HCUP databases
- How is HCUPnet different from the full HCUP databases?
HCUPnet
produces output by accessing precalculated statistics, tables and graphs of HCUP
data to produce quick results. For this reason, and to protect patient
confidentiality, not all types of queries are possible using HCUPnet. The full
HCUP databases are purchased through the HCUP Central
Distributor and require a
statistical software package (such as SAS, SPSS, or Stata) for use. Researchers
can program the software to extract the type of information they are seeking
from the databases.
HCUP Partners decide
whether to release their State-level, public-release data through the HCUP
Central Distributor and whether to have State-level statistics on HCUPnet. As a
result, data from any given State may be available through one or both sources,
and the years of participation can vary. Please review HCUPnet for a list of
participating States and years of participation. For the Central Distributor, a
summary table shows State
participation by database and year. Complete database availability and pricing
information is provided in the Database Catalog, which is found by navigating to
the online HCUP Central Distributor.
- Is the national data on HCUPnet weighted?
Yes. Unlike
the full HCUP databases that are purchased through the HCUP
Central Distributor, HCUPnet
statistics have had the weighting applied. The data from HCUPnet are national
estimates.
- How often is HCUPnet updated?
HCUPnet is
updated as databases are released. The national statistics are updated annually,
and State statistics are updated as new State data are processed. Available
States and years are listed on the HCUPnet pathways.
- HCUPnet provides national readmission statistics. Is this information
available in a full nationwide database?
Yes. Statistics
on national readmission rates are available on HCUPnet or
through the NRD. The NRD can be purchased
through the HCUP Central Distributor.
- How does HCUPnet work?
HCUPnet is
based on aggregate statistics tables to speed up data transfer and protect
individual records, so not all possible queries can be addressed. HCUPnet is
designed to walk the user through each step of building a query.
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- What additional resources are available on the HCUP-US website?
HCUP produces a number of publication series featuring HCUP data and
tools. These publications and reports provide people with ready-made sources of
statistics and guidance on a range of healthcare related subjects. Examples
include the following:
Additionally, the HCUP-US website has an HCUP Publications Search feature,
which allows visitors to search keywords for peer-reviewed articles and AHRQ
reports that used HCUP data or products to support their research. The HCUP-US
website showcases high-quality examples of articles in its Research Spotlights feature.
The
HCUP-US website also offers readily available statistics in the form of
downloadable tables/figures or interactive data visualizations. Examples include
the following:
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- What is the HCUP Online Tutorial Series?
The HCUP Online Tutorial Series is a set of
free, interactive courses designed to provide data users with information about
HCUP data and tools, as well as training on technical methods for conducting
research with HCUP data.
- What topics are available?
Topics in the Online Tutorial Series include the
following:
- HCUP Overview Course: provides a
wealth of information about HCUP data, software tools, and products.
- Load and Check HCUP Data
Tutorial: provides instructions on how to unzip (decompress)
HCUP data, save it on the computer, and load the data into a standard
statistical software package.
- Calculating Standard Errors
Tutorial: shows users how to accurately determine the precision
of the estimates produced from the HCUP nationwide databases.
- Nationwide Readmissions Database
(NRD) Tutorial: introduces users to the sampling design, key
data elements of the NRD and steps through an example of producing
national readmission rates for a specific condition.
- HCUP Sample Design Tutorial:
explains the sampling strategy of the National (Nationwide) Inpatient
Sample (NIS), Kids' Inpatient Database (KID), and Nationwide Emergency
Department Sample (NEDS) nationwide databases.
- Producing National HCUP Estimates
Tutorial: demonstrates how the NIS, KID, and NEDS can be used to
produce national and regional estimates.
- Multi-year Analysis Tutorial:
presents solutions that may be necessary when conducting analyses that
span multiple years.
- HCUP Software Tools Tutorial:
introduces users to the HCUP Software tools, which can be applied to
HCUP and other administrative databases to create new data elements from
existing data, thereby enhancing a researcher's ability to conduct
analyses. There are four modules in this course that group the HCUP
tools by the following coding systems: ICD-10-CM diagnoses, ICD-10-PCS
procedures, CPT and HCPCS Level II codes, and ICD-9-CM diagnoses and
procedures.
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HCUP Q&A can be found in HCUP's quarterly eNews.
Topics have included the following:
- What HCUP Resources are available to study COVID-19
- Commonly asked questions when using the Clinical Classifications Software
Refined (CCSR) for ICD-10-PCS Procedures
- Identifying inpatient and outpatient records in the Nationwide Emergency
Department Sample (NEDS)
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- What types of questions can HCUP User Support answer?
HCUP User Support can help (1) find, select, and
access the appropriate HCUP databases, tools, and documentation; (2) navigate
and use the HCUP-US; (3) troubleshoot issues with HCUP tools; (4) investigate
possible data or documentation errors; and (5) guide you in the appropriate use
and reporting of HCUP data.
If you have questions concerning current
HCUP database orders and invoices, downloading HCUP nationwide databases,
unzipping HCUP State or nationwide database products, or submitting required
HCUP DUAs, training certificate codes, or data re-use requests, please contact the HCUP Central Distributor.
- Are there types of questions that HCUP User Support cannot answer?
HCUP User Support cannot answer
questions related to programming software services or support, data coding,
complex analyses, or research design. Staff may be able to guide you to other
resources that are specific to your needs.
- Can HCUP User Support assist with my study design and methodology?
HCUP User Support cannot assist
with HCUP research designs. However, many users have found HCUP's Publications Search page and the
HCUP Methods Series Reports helpful
in learning how other researchers have constructed their methodology.
- Are there requirements for publishing with HCUP data?
Yes. Before publishing with HCUP data, HCUP User
Support recommends reviewing the Requirements for
Publishing With HCUP Data
page.
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