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Asthma Care Quality Improvement: A Resource Guide for State Action

Appendix F: Other Asthma-Related Data Sources

This appendix provides information on national and local data sources for asthma noted in this Resource Guide to further assist States in generating estimates or analyzing factors related to the quality of asthma care. The quality of the data is discussed throughout this section, because State leaders in quality improvement must understand issues that will be raised in the improvement process. Health care providers may argue that the data, due to limitations, do not reflect reality. They may say: "The data are the problem and not the health care system." Understanding data limitations leads to responsible use of data.

For the purposes of this Resource Guide, only data sources that are able to provide information that is nationally representative and available by State are used. Different sources use different methods, definitions, and classifications. Some sources produce estimates by State and some by national population subgroup, such as race/ethnicity, gender, age, and income.

Sources of Asthma Data in the NHQR

The asthma data in the National Healthcare Quality Report (NHQR) come from two data sources: the Healthcare Cost and Utilization Project (HCUP, provided to the Agency for Healthcare Research and Quality [AHRQ] by statewide discharge data organizations) and the National Committee for Quality Assurance's (NCQA) Health Plan Employer Data and Information Set (HEDIS®).

Healthcare Cost and Utilization Project

HCUP is a public-private partnership sponsored by AHRQ with 37 participating States that covered about 90 percent of U.S. discharges in the United States in 2004. Discharge data from 28 of these States are available online through HCUPnet ( The participating statewide data organizations (government, hospital association, or other private organization) provide their statewide hospital discharge data to HCUP for reformatting into standardized files. While national asthma estimates from HCUP are included in the NHQR, State-level data are reported in the NHQR only for one special analysis of admissions for asthma.

The following HCUP Partners provided data for the 2004 HCUP Nationwide Inpatient Sample:

State HCUP Partner
Arizona Arizona Department of Health Services
Arkansas Arkansas Department of Health & Human Services
California Office of Statewide Health Planning & Development
Colorado Colorado Health & Hospital Association
Connecticut Integrated Health Information (Chime, Inc.)
Florida Agency for Health Care Administration
Georgia Georgia Hospital Association (GHA)
Hawaii Hawaii Health Information Corporation
Illinois Illinois Department of Public Health
Indiana Indiana Hospital & Health Association
Iowa Iowa Hospital Association
Kansas Kansas Hospital Association
Kentucky Cabinet for Health and Family Services
Maryland Maryland Health Services Cost Review Commission
Massachusetts Massachusetts Division of Health Care Finance and Policy
Michigan Michigan Health & Hospital Association
Minnesota Minnesota Hospital Association
Missouri Hospital Industry Data Institute
Nebraska Nebraska Hospital Association
Nevada Nevada Department of Human Resources
New Hampshire New Hampshire Department of Health and Human Services
New Jersey New Jersey Department of Health & Senior Services
New York New York State Department of Health
North Carolina North Carolina Department of Health and Human Services
Ohio Ohio Hospital Association
Oregon Oregon Association of Hospitals & Health Systems
Rhode Island Rhode Island Department of Health
South Carolina South Carolina State Budget & Control Board
South Dakota South Dakota Association of Healthcare Organizations
Tennessee Tennessee Hospital Association
Texas Texas Department of State Health Services
Utah Utah Department of Health
Vermont Vermont Association of Hospitals and Health Systems
Virginia Virginia Health Information
Washington Washington State Department of Health
West Virginia West Virginia Health Care Authority
Wisconsin Wisconsin Department of Health & Family Services

Contact information for these statewide data organizations is available at: Additional information on HCUP data can be found at:

The main limitation of HCUP data (or any administrative billing data) is that the data are collected primarily for the purpose of reimbursement, and what is coded as clinical diagnoses and procedures can be affected by reimbursement incentives.1 Such incentives can encourage or discourage coding of specific types of conditions or treatments. In addition, the data do not include detailed clinical information (e.g., physiologic measures) beyond diagnoses and procedures, which are useful in determining patient severity of illness. Nevertheless, HCUP data can be used for many purposes, provided that the bias of coding is considered and ruled out as inconsequential. Thus, while administrative hospital data can be mined for clues to quality of care, analysts should be alert for whether the data contain incomplete entries or inadequate clinical detail.

AHRQ has developed the Quality Indicators for use with HCUP and other hospital administrative data. These indicators use sophisticated clinical algorithms of inclusions and exclusions to define patients with similar characteristics and then calculate the outcomes of these groups of patients across different settings and populations. The algorithms have been tested, reviewed, and hewn by clinical consensus panels under AHRQ sponsorship. The AHRQ Quality Indicators include the Prevention Quality Indicators, which estimate rates of avoidable hospital admissions, including separate indicators for pediatric and adult asthma admissions, as an indirect measure of the quality of ambulatory asthma care in the United States. As tools for local quality improvement, the AHRQ Quality Indicators can be used as screens for quality problems that call for more in-depth local study; they are not considered definitive measures of local quality of care. As national measures they capture trends in quality as well as coding of diagnoses. National estimates of the asthma Prevention Quality Indicators are part of the 2003 and 2004 NHQR and NHDR; State estimates are in the 2004 NHQR. Additional information on the AHRQ Quality Indicators is available at:

Health Plan Employer Data and Information Set (HEDIS)

HEDIS® collects data from health plans across the country. HEDIS® is a set of standardized performance measures designed to ensure that purchasers and consumers have the information they need to reliably compare the performance of managed health care plans. The performance measures in HEDIS® are related to many significant public health issues such as cancer, heart disease, smoking, asthma and diabetes. HEDIS® also includes a standardized survey of consumers' experiences that evaluates plan performance in areas such as customer service, access to care and claims possessing. HEDIS® is sponsored, supported, and maintained by the National Committee for Quality Assurance.

Because HEDIS® data are collected at the health plan level, State estimates cannot be made. To provide regional estimates, each health plan is assigned to the State in which the health plan headquarters are located, but these are not necessarily where the practices are located. HEDIS® data are also limited in that they are relevant to care provided only under managed health care plans.

1 Keating N, Landrum M, Landon B, Ayanian J, Borbas C, Guadagnoli E. Managing chronic illness in managed care settings: Measuring the quality of diabetes care using administrative data: Is there a bias? Health Services Research 2003;38(6):1529-45.

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Other Sources of Data on Asthma Care

Asthma-related measures from the following sources discussed in this Resource Guide are not yet included in the NHQR. (For detailed information on State-level Behavioral Risk Factor Surveillance System (BRFSS) measures not yet included in the NHQR, go to Appendix E.)

National and Setting-Specific Data Sources

Medical Expenditure Panel Survey (MEPS)

MEPS is a family of surveys, including a Household Survey and surveys of related health care providers. Information is collected annually on health care utilization, expenditures, and health insurance coverage. For the most part, MEPS data are collected using computer-assisted, in-person interviews. The asthma component is collected via a separate paper and pencil questionnaire distributed to respondents who report that they have been diagnosed with asthma. More information about MEPS data and methods is available at:

MEPS reports national rates by national subgroup for the percentages of asthma patients who used prescription asthma medications, inhaled steroids, and peak flowmeters. Other measures of asthma process of care are not captured in this data set. The following table shows MEPS data on these measures for 2000:

Asthma Medication and Peak Flowmeter Use for Patients with Asthma by Age Group, 2000

Measure Total Under
Age 18
Age 18
and older
Percent who used:      
Asthma medication 86.5 91.2 84.3
Inhaled steroids 49.8 42.3 53.5
Peak flowmeter in home 31.3 27.5 33.1

Source: Agency for Healthcare Research and Quality (2003). MEPS Statistical Brief #13, Asthma Treatment: Use of Medications and Devices, 2000 (Plugin Software Help).

MEPS collects expenditure data from a national sample but does not collect data by State; thus State-level estimates are not available. The following table from MEPS shows total expenses for the category of "COPD, asthma" by site of service:

Total expenses, in millions of dollars, for COPD, asthma by site of service, 1996-2002

Year Total Outpatient and
office-based medical
provider visits
Hospital inpatient stays Emergency room visits Prescribed medicines Home health care
2002 45,262.78 11,923.53 12,464.81 1,642.40 15,150.31 4,081.72
2001 44,404.43 9,825.75 16,324.51 1,612.99 13,327.22 3,313.96
2000 36,487.99 7,225.14 13,929.82 1,119.92 8,750.69 5,460.57
1999 33,651.40 7,115.61 11,982.60 1,197.51 8,239.30 5,116.38
1998 31,707.10 6,820.20 14,489.72 915.37 6,719.09 2,762.73
1997 28,973.39 6,356.35 13,256.91 1,090.62 6,100.09 2,169.43
1996 28,594.88 6,895.89 12,702.23 942.14 5,630.05 2,424.57

Source: Agency for Healthcare Research and Quality. MEPS Compendium of Tables-Medical Expenditures by Condition (1996-2002). Total expenses for conditions by site of service: United States, 1997. March 3, 2003. Medical Expenditure Panel Survey Component Data.

National Hospital Discharge Survey

The NHQR uses the National Hospital Discharge Survey (NHDS) for one outcome measure—estimated annual rate of hospitalizations for asthma. The National Center for Health Statistics at the Centers for Disease Control and Prevention (CDC) uses a national sample of hospitals and a sample of their discharges to collect administrative hospital records for the NHDS (similar to HCUP). The sample consists of about 270,000 inpatient records from about 500 hospitals and is representative of inpatient discharges nationally. Additional information on NHDS data is available at:

The limitation of NHDS data are similar to those for HCUP data (described above) because NHDS also uses discharge records or inpatient claims for reimbursement. In addition, although NHDS is a true probability sample, it has a much smaller size than HCUP. As a result, many subgroup estimates that can be made with HCUP cannot be supported with NHDS data. The NHDS cannot produce State-level estimates.

National Asthma Survey

The National Asthma Survey, a national sample of households interviewed by phone, was conducted by CDC beginning in 2004. The survey contains questions that can be used to develop measures similar to BRFSS asthma measures in addition to other measures related to processes of asthma care including asthma education, peak flow meter use, spirometer use, demographic information of persons with asthma, and others. Pilot survey data were released in 2005. (Results of pilot tests in four States are available at:

National Health Interview Survey

Conducted by CDC's National Center for Health Statistics, the National Health Interview Survey collects data on asthma prevalence for all ages and for children only. Twelve-month prevalence data were collected for children from 1980 to 1996 and for all ages from 1982 to 1996. Beginning in 1997, the survey asks questions on lifetime diagnosis and 12-month attack prevalence; a question on current prevalence (i.e., "Do you still have asthma?") was added in 2001. The NHIS also includes questions on the number of school days missed by children and the number of workdays missed by adults due to asthma.

National Ambulatory Medical Care Survey/National Hospital Ambulatory Medical Care Survey (NAMCS/NHAMCS)

These surveys are conducted annually by CDC's National Center for Health Statistics. NAMCS surveys office-based physicians who are randomly assigned to a 1-week reporting period. The survey form includes questions on reason for the visit and physician diagnosis as well as whether the patient has various chronic diseases, including asthma, regardless of diagnosis. NHAMCS collects similar data for hospital emergency and outpatient departments over a 4-week reporting period. Recent findings related to asthma from these and other NCHS surveys can be found at:

Health Care Setting-Specific Data Sources

The following sources collect asthma care quality data at the level of specific health care settings rather than collecting nationally representative or state level data. Therefore, data from these sources are useful for informing initiatives or policies in the appropriate health care setting but not necessarily for broad statewide programs. However, the availability of these data point to important opportunities for collaborations with other health providers and sectors to improve the quality of asthma care.

  • The Joint Commission on Accreditation of Healthcare Organizations, an organization that oversees the quality of hospitals and other health care organizations, collects hospital data on disease-specific care, including asthma.
  • Health Disparities Collaboratives, learning processes of the Health Resources and Services Administration's (HRSA) Bureau of Primary Health Care, are disease specific (diabetes, heart disease, and asthma) and include community health centers across the Nation.
  • National Institute for Children's Healthcare Quality Learning Collaboratives are partnerships and learning networks that collect quality data on care for specific diseases in primary care practices. NICHQ efforts aim to measure and improve quality of care and build structural support for quality improvement.

Local Data Sources

Below are summaries of some local data sources that have been developed to assess more closely the processes of asthma care for specific populations in specific geographic areas. (Go to Appendix D for descriptions of measures from local and other health care setting data sources.)

Chicago Asthma Surveillance Initiative (CASI)

The goal of CASI is to develop a community-wide surveillance program that characterizes and monitors asthma care in the Chicago area in greater detail than other public health surveillance. To accomplish this, CASI surveyed Chicago-area hospitals, emergency departments, primary care physicians, specialty care physicians, pharmacists, managed care organizations, the general public, and persons or families affected by asthma to learn about asthma care and its outcomes. Seven surveys are included: emergency department, hospital, managed care, primary care physician, specialty care physician, pharmacist, and asthma survey of the general population. The CASI surveys were designed to assist the Chicago Asthma Consortium in setting program priorities and to evaluate the impact of these programs over time. The first promising effect stemming from the CASI surveys was the creation of the Chicago Emergency Department Asthma Collaborative in 1997 in which 28 EDs agreed to participate in a 1-year community-based collaborative aimed at improving ED asthma care.2

Guide to Improving Asthma Care in Oregon

The goal of this Oregon Asthma Program guide is to steer efforts to improve asthma management and to define appropriate indicators for monitoring the quality of medical care provided to Oregonians with asthma. The guide establishes nine priority areas including: periodic assessment and monitoring of asthma; spirometry; coordination of care; written asthma action plan; asthma education; pharmacology; influenza immunization; assessment, education, management, and treatment of allergens and irritants; and asthma recommendations for health systems. The guide was developed through a consensus process and includes population-based goals and indicators. The guide does not address all the care a patient with asthma may need. Rather, it is based on a set of procedures that are measurable for defined populations and therefore lend themselves to systematic monitoring. The guide can be accessed at:

Michigan Quality Improvement Consortium (MQIC)

The goal of the Michigan Quality Improvement Consortium is to establish and implement a core set of clinical practice guidelines and performance measures for Michigan health plans. The interventions designed and implemented by each plan to improve consistent delivery of services are at the discretion of individual plans; but guidelines, performance goals, measurement methodology, and performance reporting are standardized. The MQIC asthma guideline recommends provision of specific services at least annually including a written action plan for self-management and education regarding use of peak flowmeter, inhaler, spacer and medication, recognition/treatment of symptoms and when to seek medical attention, identification, and avoidance of triggers and smoking cessation counseling.

New York City Childhood Asthma Initiative (NYCCAI)

The New York City Department of Health and Mental Hygiene's Childhood Asthma Initiative is a public health effort to reduce asthma morbidity among children 0 to 18 years of age. Expected outcomes of the NYCCAI include reductions in hospitalizations, ED visits, and school absences due to asthma and improvements in management of childhood asthma among families. The NYCCAI is building on existing research and educational and clinical efforts, resulting in a coordinated and comprehensive effort to understand, treat, and prevent asthma in New York City.3

2Weiss KB, Grant EN. The Chicago Asthma Surveillance Initiative: a community-based approach to understanding asthma care. Chest 1999;116:141S-145S.
3Garg R, Karpati A, Leighton J, Perrin M, Shah M. Asthma Facts, Second Edition. New York City Department of Health and Mental Hygiene, May 2003. Available at:

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Page last reviewed October 2014
Page originally created September 2012
Internet Citation: F. Other Asthma-Related Data Sources. Content last reviewed October 2014. Agency for Healthcare Research and Quality, Rockville, MD.


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