U.S. Department of Health and Human Services, Agency for Healthcare Research and Quality (AHRQ).
The Healthcare Cost and Utilization Project (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 discharge-level health care data.
HCUP includes a collection of longitudinal hospital care data in the United States, with all-payer, encounter-level information beginning in 1988. These databases enable research on a broad range of health policy issues, including cost and quality of health services, medical practice patterns, access to health care programs, and outcomes of treatments at the national, State, and local market levels.
Four HCUP discharge datasets were used in this report:
The HCUP State Inpatient Databases (SID) include a powerful set of hospital databases from HCUP Partner organizations in 47 States and the District of Columbia. Together, the SID encompasses about 97 percent of all U.S. community hospital discharges. SID contains a core set of clinical and nonclinical information on all patients, regardless of payer, including people covered by Medicare, Medicaid, and private insurance, as well as uninsured people. In addition to the core set of uniform data elements common to all of the SID, some states report other data elements, such as patient race.
For generating national Quality Indicator estimates beginning in data year 2016, SID were combined to create a nationally weighted analysis file because of variation in the availability of both race/ethnicity data and indicators of diagnoses being present on admission, which are required for some of the AHRQ Quality Indicators. SID meeting the following inclusion criteria were included in the nationally weighted analysis file: (1) less than 10 percent of discharges failed edit checks on indicators of diagnoses being present on admission (POA); (2) the SID included information on day of principal and secondary procedure days; and (3) the SID included good reporting of race/ethnicity data. After hospitals and discharges that failed POA and race/ethnicity edits were excluded, the remaining discharges were weighted to the universe of community hospitals in the United States, excluding rehabilitation and long-term acute care facilities. In data year 2016, the nationally weighted analysis file includes data from 34 SID and over 30.2 million discharges. The following States were included: AR, AZ, CA, CO, FL, GA, HI, IL, IN, KS, KY, LA, MA, MD, ME, MI, MN, MO, MS, MT, NC, NJ, NM, NV, NY, OH, OR, PA, RI, SC, TN, TX, VA, and WA.
The HCUP National Inpatient Sample (NIS) is drawn from all States participating in HCUP, covering more than 97 percent of the U.S. population. The NIS approximates a 20-percent stratified sample of discharges from U.S. community hospitals, excluding rehabilitation and long-term acute care hospitals. The large sample size in the enables analyses of rare conditions, uncommon treatments, and special patient populations. The 2016 NIS includes inpatient data from 46 States plus the District of Columbia.
The Nationwide Emergency Department Sample (NEDS) was constructed using the HCUP State Emergency Department Databases (SEDD) and the SID. The SEDD captures encounter information on emergency department (ED) visits that do not result in an admission (i.e., treat-and-release visits and transfers to another hospital). The SID contains information on patients initially seen in the ED and then admitted to the same hospital. The NEDS was created to enable analyses of ED utilization patterns and is the largest all-payer ED database that is publicly available in the United States. The NEDS is a 20-percent stratified sample of hospital-owned EDs in the U.S. Thirty-seven States and the District of Columbia contributed data to the 2016 NEDS: AR, AZ, CA, CT, DC, FL, GA, HI, IA, IL, IN, KS, KY, MA, MD, ME, MN, MO, MS, MT, NC, ND, NE, NJ, NV, NY, OH, OR, RI, SC, SD, TN, TX, UT, VT, WI, and WY. These States are geographically dispersed and account for 68.7 percent of the total U.S. resident population and 78.2 percent of all U.S. ED visits.
The HCUP NIS, NEDS, and SID contain more than 100 clinical and non-clinical data variables, including age, sex, patient race/ethnicity, diagnoses, procedures, length of stay, discharge status, expected source of payment, total charges, hospital size, ownership, region, and teaching status. The HCUP databases combine categories for patient race/ethnicity categories, resulting in the following subgroups: Hispanic of all races, and non-Hispanic African Americans, Asians and Pacific Islanders, and Whites. Not all states uniformly collect race and ethnicity data; when a state and its hospitals collect Hispanic ethnicity separately from race, HCUP uses Hispanic ethnicity to override any other race category.
Many of the QDR measures that use HCUP data are based on Version 7.0.1 of the AHRQ Quality Indicators (QIs), a set of algorithms that may be applied to hospital administrative data to quantify quality issues among inpatient populations. The QIs fall into four categories:
Inpatient Quality Indicators (IQIs) reflect quality of care in hospitals and currently include 19 mortality indicators for conditions or procedures and indicators for 6 procedures for which outcomes may be related to the volume of procedures are included in the IQIs.
Prevention Quality Indicators (PQIs) assess hospital admissions for 13 ambulatory care-sensitive conditions, that evidence suggests may be avoided, in part, through high-quality ambulatory care. Version 7.0.1 of the PQI software also includes 4 composite measures assessing potentially avoidable hospitalizations overall, for acute conditions, for chronic conditions, and for diabetes-specific conditions.
Patient Safety Indicators (PSIs) reflect potential inpatient complications and other patient safety concerns following surgeries, other procedures, and childbirth. Version 7.0.1 of the PSI software has 18 measures.
Pediatric Quality Indicators (PDIs) examine 16 conditions that pediatric patients experience within the health care system that may be preventable by changes at the system or provider level. Version 7.0.1 of the PQI software includes 3 composite measures assessing hospitalizations overall, for acute conditions, and for chronic conditions. In earlier versions of the QI software, some PDI measures were part of the IQI, PSI, and PQI modules.
For reporting in 2016, we applied the QI software to the HCUP databases without modification. Rates prior to 2016 are not reported because of the transition to the International Classification of Diseases, Tenth Edition, Clinical Modification/ Procedure Coding System. Observed (un-adjusted) rates are provided, as risk adjustment was unavailable in the AHRQ QI version 7.0.1 software.
The population targeted by HCUP databases includes any person, U.S. citizen or foreign, using non-Federal, non-rehabilitation, community hospitals in the United States as defined by AHA. AHA defines community hospitals as "all non-Federal, short-term, general, and other specialty hospitals, whose facilities and services are available to the public (Health Forum, LLC ©2017)." Included among community hospitals are specialty hospitals, such as obstetrics-gynecology, ear-nose-throat, short-term rehabilitation, orthopedic, and pediatric institutions. Also included are public hospitals and academic medical centers. The NIS and analyses of the SID for this report excluded short-term rehabilitation hospitals, long-term acute-care hospitals, psychiatric hospitals, and alcoholism/chemical dependency treatment facilities.
Although not all States participate in the HCUP database, the NIS, the NEDS, and the nationally weighted analysis files are weighted to give national estimates of all U.S. community hospitals, excluding rehabilitation and long-term, acute-care hospitals, as identified by the AHA Annual Survey (Health Forum, LLC © 2017).
Age, sex, race/ethnicity, expected primary payer, median household income of the patient's ZIP Code, urbanized location, and region of the United States.
National, four U.S. Census Bureau regions, States (for States participating in SID that agree to the release).
Agency home page: http://www.ahrq.gov.
Data system home page: https://www.ahrq.gov/data/hcup/index.html.
AHRQ Quality Indicators: http://www.qualityindicators.ahrq.gov.
Barrett M, Coffey R, Houchens R, Heslin K, Moles E, Coenen N. Methods Applying AHRQ Quality Indicators to Healthcare Cost and Utilization Project (HCUP) Data for the 2017 National Healthcare Quality and Disparities Report (QDR). 2018. HCUP Methods Series Report # 2018-01 ONLINE. May 11, 2018. U.S. Agency for Healthcare Research and Quality. Available: http://www.hcup-us.ahrq.gov/reports/methods/methods.jsp.
Agency for Healthcare Research and Quality. Inpatient Quality Indicators: Technical Specifications, AHRQ Quality Indicators, Version 7.0.1 SAS. Rockville, MD: Agency for Healthcare Research and Quality, September 2017.
Agency for Healthcare Research and Quality. Patient Safety Indicators: Technical Specifications, AHRQ Quality Indicators, Version 7.0.1 SAS. Rockville, MD: Agency for Healthcare Research and Quality, September 2017.
Agency for Healthcare Research and Quality. Pediatric Quality Indicators: Technical Specifications, AHRQ Quality Indicators, Version 7.0.1 SAS. Rockville, MD: Agency for Healthcare Research and Quality, September 2017.
Agency for Healthcare Research and Quality. Prevention Quality Indicators: Technical Specifications, AHRQ Quality Indicators, Version 7.0.1 SAS. Rockville, MD: Agency for Healthcare Research and Quality, September 2017.
For detailed information about QI measures, refer to the individual guides to the quality indicators listed below, available from the archives at http://www.qualityindicators.ahrq.gov.
Alaska Department of Health and Social Services
Alaska State Hospital and Nursing Home Association
Arizona Department of Health Services
Arkansas Department of Health
California Office of Statewide Health Planning and Development
Colorado Hospital Association
Connecticut Hospital Association
Delaware Division of Public Health
District of Columbia Hospital Association
Florida Agency for Health Care Administration
Georgia Hospital Association
Hawaii Health Information Corporation
Illinois Department of Public Health
Indiana Hospital Association
Iowa Hospital Association
Kansas Hospital Association
Kentucky Cabinet for Health and Family Services
Louisiana Department of Health
Maine Health Data Organization
Maryland Health Services Cost Review Commission
Massachusetts Center for Health Information and Analysis
Michigan Health & Hospital Association
Minnesota Hospital Association (provides data for Minnesota and North Dakota)
Mississippi Department of Health
Missouri Hospital Industry Data Institute
Montana Hospital Association
Nebraska Hospital Association
Nevada Department of Health and Human Services
New Hampshire Department of Health & Human Services
New Jersey Department of Health
New Mexico Department of Health
New York State Department of Health
North Carolina Department of Health and Human Services
North Dakota (data provided by the Minnesota Hospital Association)
Ohio Hospital Association
Oklahoma State Department of Health
Oregon Association of Hospitals and Health Systems
Oregon Office of Health Analytics
Pennsylvania Health Care Cost Containment Council
Rhode Island Department of Health
South Carolina Revenue and Fiscal Affairs Office
South Dakota Association of Healthcare Organizations
Tennessee Hospital Association
Texas Department of State Health Services
Utah Department of Health
Vermont Association of Hospitals and Health Systems
Virginia Health Information
Washington State Department of Health
West Virginia Department of Health and Human Resources, West Virginia Health Care Authority
Wisconsin Department of Health Services
Wyoming Hospital Association