Chapter 1. Introduction and Methods

In 1999, Congress directed the Agency for Healthcare Research and Quality (AHRQ) to produce an annual report, starting in 2003, to track "prevailing disparities in health care delivery as it relates to racial factors and socioeconomic factors in priority populations." Although the emphasis is on disparities related to race, ethnicity, and socioeconomic factors, this directive includes a charge to examine disparities in "priority populations"—groups with unique health care needs or issues that require special focus. AHRQ, with support from the Department of Health and Human Services (HHS) and private-sector partners, designed and produced th

The first NHDR was a comprehensive national overview of disparities in health care among racial, ethnic, and socioeconomicⁱ groups in the general U.S. population and within priority populations. This 2009 NHDR represents the seventh release of this report. It continues to focus on a subset of core measures that make up the most important and scientifically supported measures in the full NHDR measure set. The report also includes trends in health care disparities, as well as the degree to which health care disparities for racial and ethnic minorities and poor populations have lessened.

This chapter summarizes AHRQ's methodological approach in producing the 2009 NHDR. Issues related to changes in measures, additional data sources, and modifications to presentation format are summarized below. Material that is new in this year's report is specifically highlighted and includes:

• A new section on Lifestyle Modification. Measures include:
  • Counseling smokers to quit smoking.
  • Advice to obese adults about healthy eating.
• A new section on Functional Status Preservation and Rehabilitation. Measures include:
  • Older women who reported being screened for osteoporosis.
  • Adult home health care patients whose ability to walk or move around improved.
• A new section on Supportive and Palliative Care (changed from Nursing Home, Home Health, and Hospice Care). Measures include:
  • Long-stay nursing home residents with physical restraints.
  • High-risk long-stay nursing home residents and short-stay residents with pressure sores.
  • Adult home health care patients who were admitted to the hospital.
  • Hospice patient caregivers who perceived patient was not referred to hospice at the right time.
  • Hospice patients who did not receive the right amount of medicine for pain.
• Additional data on timeliness of care that include
• A focus in the Patient Safety section on health care-acquired infections that includes a measure on surgery patients who received appropriate timing of antibiotics.
• Data on the diversity of dental professionals in the workforce.
• A focus in the Patient Centeredness section on measures of care coordination, including:
  • Patients who reported that they always received test results.
  • Adult hospital patients with heart failure who were given complete written discharge instructions.
• A new measure in Chapter 3, Access to Health Care, on the high financial burden of health care.
• Supplemental data on Asian and Hispanic subpopulations, including:
  • Colorectal cancer screening.
  • Influenza vaccinations.
  • Diabetes care.
  • Provider-patient communication.
  • Uninsurance.
• Additional data on Native Hawaiians and Other Pacific Islanders (NHOPIs),ⁱⁱ including
  • Cholesterol screening.
  • Colorectal cancer screening.
  • Hospitalizations for pneumonia.
  • Difficulty getting care due to cost.
• Supplemental data on American Indians and Alaska Natives (AI/ANs), including:
  • Uncontrolled diabetes.
  • Perforated appendixes.
• Additional data on birth-related trauma in the section on Women.
• Additional data on heart attack mortality in the section on Residents of Rural Areas.
• Continued expanded focus on individuals with disabilities, including:
  • Delayed dental care.
  • Dental visits.
  • High financial burden of health care.

As in previous years, the 2009 NHDR was planned and written by AHRQ staff with the support of AHRQ's National Advisory Council and the Interagency Work Group for the NHDR, which includes representatives from every HHS operating component. 

How This Report Is Organized

The basic structure of the 2009 NHDR includes the following chapters:

• Highlights summarizes key themes and highlights from the 2009 report.
• Chapter 1: Introduction and Methods documents the organization, data sources, and methods used in the 2009 report and describes major changes from previous reports.
• Chapter 2: Quality of Health Care examines disparities in quality of health care in the general U.S. population. Measures of quality of health care used in this chapter are identical to measures used in the National Healthcare Quality Report (NHQR) except when data to examine disparities are unavailable. Sections cover four components of health care quality:
  • Effectiveness. (Eight clinical areas: cancer, diabetes, end stage renal disease, heart disease, HIV and AIDS, maternal and child health, mental health and substance abuse, and respiratory diseases; and three types of health care services that typically cut across clinical conditions: lifestyle modification, functional status preservation and rehabilitation, and supportive and palliative care).
  • Patient safety.
  • Timeliness.
  • Patient centeredness.
• Chapter 3: Access to Health Care examines disparities in access to health care in the general U.S. population. Sections cover two components of health care access:
  • Barriers and facilitators to health care.
  • Health care utilization.
• Chapter 4: Priority Populations examines disparities in quality of and access to health care among AHRQ's priority populations, including:
  • Racial and ethnic minorities.
  • Recent immigrant and limited-English-proficient populations.
  • Low-income groups.
  • Women.
  • Children.
  • Older adults.
  • Residents of rural areas.
  • Individuals with disabilities and special health care needs.

The following appendixes will be available online:

• Data Sources provides information about each database analyzed for the NHDR, including data type, sample design, and primary content.
• Detailed Methods provides detailed methods for selected databases analyzed for the NHDR.
• Measure Specifications provides information about how to generate each measure analyzed for the NHDR. It includes measures highlighted in the report text, as well as other measures that were examined but not included in the text. It also includes information about the summary measures used in the report.
• Data Tables provides detailed tables for most measures analyzed for the NHDR, including measures highlighted in the report text, as well as other measures that were examined but not included in the text. A few measures cannot support detailed tables and are not included in the appendix.ⁱⁱⁱ When data are available:
  • Race tables and ethnicity tables are stratified by age, gender, geographic location, and one or more socioeconomic variables (i.e., household income, education, insurance, and/or area income).
  • Socioeconomic tables are stratified by age, gender, geographic location, race, and ethnicity.

Presentation of the Measure Set

Core Measures

This 2009 NHDR continues to focus on a consistent subset of measures, the "core" measures, which includes the most important and scientifically supported measures in the full NHDR measure set. In 2005, the Interagency Work Group selected the core measures from the full measure sets, and findings based on these measures are presented each year. In addition, "noncore" measures are included in summary statistics and may be presented to complement core measures in key areas. For some topics, the NHDR uses alternating sets of core measures. These measures, which relate to cancer prevention and childhood preventive services, are listed in Table 1.1.

Table 1.1. Alternating core measures

*The measures listed in this column will be reported in the 2010 reports.

All core measures fall into two categories; process measures, which track receipt of medical services, and outcome measures, which in part reflect the results of medical care (Table 1.2). Not all process and outcome measures are reported for all conditions due to data limitations and other limitations (refer to Chapter 1 of the 2005 NHDR for core report measure selection criteria).

Ideally, process measures and the outcome measures they could affect would be tracked in tandem. However, data to support such process-outcome measurement pairs are not typically available. Related process and outcome measures in the 2009 NHDR core measure set are listed in Table 1.2. Other core measures are listed in Table 1.3.

Table 1.2. Related core process and outcome measures (Measures that include data for all racial and ethnic groups and that are included in the summary analyses in the Highlights to this report are in italics.)

*Not included in core measure counts in 2009.

Table 1.3. Other core process and outcome measures

Note: Beginning with the 2008 NHDR, all alternating core measures are included in the summary of core measures in order to show consistent measures in the Highlights chapter of each year of the NHDR. Table 1.1 lists all alternating core measures.

Composite Measures

Policymakers and others have voiced their support for composite measures because these measures can be used to facilitate understanding of information from many different measures. The effort to develop new composites is ongoing. In 2006, a number of new composite measures were added.^iv Composite measures, which now make up about 20% of the core measures, are listed in Table 1.4.

Composite measures in the NHDR and NHQR are created a variety of different ways. When possible, an appropriateness model is used to create composite measures. It is sometimes referred to as the "all-or-none" approach because it is calculated based on the number of patients who received all appropriate services. One example of this model is the diabetes composite, in which a patient who receives only one or two of the three services would not be counted as having received the recommended care.

In cases where insufficient data are available to apply an appropriateness model, an opportunities model may be applied. The opportunities model assumes that each patient needs and has the opportunity to receive one or more processes of care but not all patients need the same care. Composite measures that use this model summarize the proportion of appropriate care that is delivered. The denominator for an opportunities model composite is the sum of opportunities to receive appropriate care across a panel of process measures The numerator is the sum of the appropriate services that are actually delivered. The composite measure of recommended hospital care for heart attack is an example where this model is applied. The total number of patients who actually receive treatments represented by individual components of the composite measure (e.g., aspirin therapy within 24 hours, beta blocker within 24 hours, smoking cessation counseling) is divided by the sum of all of these opportunities to receive appropriate care.

Composite measures that relate to rates of complications of hospital care are postoperative complications and complications of central venous catheters. For these complication rate composites, an additive model is used that sums individual complication rates. Thus, for these composites, the numerator is the sum of individual complications and the denominator is the number of patients at risk for these complications. The composite rates are presented as the overall rate of complications. The postoperative complications composite is a good example of this type of composite measure: If 50 patients had a total of 15 complications among them (regardless of their distribution), the composite score would be 30%.

Table 1.4. Composite measures in the 2009 NHQR and NHDR

* ACE = angiotensin-converting enzyme; ARB = angiotensin receptor blocker.

Presentation of Disparities

The 2009 NHDR and its companion NHQR continue to be formatted as chartbooks. The 2009 reports have been improved to show charts and data in a more readable format and to provide more concise summaries of the findings in each chart.

Each section in the 2009 report begins with a description of the importance of the section's topic in a standardized format. After introductory text, chart figures and accompanying findings highlight a small number of core measures relevant to this topic. When data are available, these charts typically show contrasts by:

• Race—Blacks, Asians,^v NHOPIs, AI/ANs, and people of more than one race compared with Whites.
• Ethnicity—Hispanics compared with non-Hispanic Whites.^vi
• Income—Poor, near-poor, and middle-income people compared with high-income people.^vii
• Education—People with less than a high school education and high school graduates compared with people with any college education.
• Geographic location—People who reside in micropolitan (total) areas are compared with metropolitan (total) areas. Within metropolitan areas, people who reside in large central, large fringe, medium, or small metropolitan areas are compared with metropolitan (total). Within nonmetropolitan areas, people who reside in micropolitan and noncore statistical areas are compared with nonmetropolitan (total). Refer to Chapter 4, Residents of Rural Areas, for further information on definitions and methods.

Almost all core measures and composite measures have multiple years of data, so figures typically illustrate trends over time. When data support stratified analyses, a figure showing racial and ethnic differences stratified by socioeconomic factors is included. These data are summarized in bullet format. Figures include a note about the reference group for population-based measures and the denominator for measures based on services or events.

For some measures with supporting data, regression models were run and used to help interpret bivariate and stratified results. (These are discussed in more detail in the Bivariate and Multivariate Analyses section, below.)^viii

Gaps between priority populations and the reference group are characterized as growing larger, getting smaller, or not changing. This is part of the effort by HHS and AHRQ to provide information on where the Nation is—and is not—making progress in reducing disparities in health care.

Findings presented in the text meet report criteria for importance^ix; comparisons not discussed in the text do not meet these criteria. However, absence of differences that meet criteria for importance should not be interpreted as absence of disparities.Often, large differences between groups did not meet criteria for statistical significance because of small sample sizes and limited power. In addition, significance testing used in this report does not take into account multiple comparisons.

Effectiveness measures for each condition or care setting are organized further into categories that reflect the patient's need for preventive care, treatment of acute illness, or management of chronic conditions. Further detail on each of these categories and the measures included can be found in Chapter 2, Quality of Health Care.

Trends in Health Care Quality and Access

As in previous NHDRs, the 2009 report uses the earliest and most recent available NHDR data estimates for each measure to calculate average annual rate of change for the general U.S. population and for each racial, ethnic, and socioeconomic group. Consistent with Health, United States,¹ the geometric rate of change, which assumes the same rate each year between the two time periods, has been calculated for the 2009 NHDR and NHQR.^x

Two criteria are applied to determine whether a significant trend exists:

• First, the difference between the oldest and most recent estimates must be statistically significant at alpha=0.05.
• Second, the average annual rate of change must be at least 1% to be considered statistically significant when the measures are framed either as a favorable outcome or as an adverse outcome.

For example, assume that a favorable outcome, receipt of a needed service, increased from 90% to 94% over a 5-year period. To assess meaningfulness, statistical significance of this difference would first be assessed using a two-tailed test. If significant with alpha≤0.05, the average annual rate of change would then be calculated using the geometric rate of change formula. In this case, [(94/90)^1/5 - 1] x 100 yields an average annual rate of change of 0.9% per year, less than our threshold of 1% per year. The measure is then converted into an adverse outcome, lack of receipt of a needed service, which decreased from 10% to 6% over the time period. Applying the geometric rate of change formula, [(6/10)^1/5 - 1] x 100, yields an average annual rate of change of -9.7% per year. Because this rate of change with the measure framed negatively as an adverse outcome exceeds our 1% threshold, we consider this change to be meaningful.

Only changes over time that meet these criteria are discussed in the 2009 reports. Changes in disparities are categorized as follows:

• Core measures for which the relative differences are changing less than 1% per year are identified as staying the same.
• Core measures for which the relative differences are becoming smaller at a rate of more than 1% per year in the same direction are identified as improving.
• Core measures for which the relative differences are becoming larger at a rate of more than 1% per year in the same direction are identified as worsening.
• Changes of greater than 5% per year are also differentiated from changes between 1% and 5% per year in some figures.

An additional constraint relates to trends among specific racial and ethnic groups. Different Federal databases completed transition to the new Federal standards for racial and ethnic data that were required by 2003 at different times. These new standards created two separate racial categories: Asian and NHOPI. In addition, individuals could report more than one race. Since a large proportion of AI/ANs identify as mixed race, many AI/ANs may be categorized as more than one race. In contrast, effects on estimates for Whites, Blacks, and Hispanics were proportionately much smaller. Therefore, the 2009 NHDR, as in the previous year, shows shorter trends (i.e., fewer years of data) for groups directly or significantly affected by the new standards, such as Asian, NHOPI, AI/AN, and multiple-race individuals.

Bivariate and Multivariate Analyses

Bivariate analyses are included for some measures for which data are available to examine the interrelationship between race/ethnicity and socioeconomic factors. This year, the NHDR also examines the interrelationship between insurance status and income for quality of care in more depth.  This relationship is shown for some selected measures through the use of bivariate analyses in Chapter 4, Priority Populations.

To further address the interrelationships among different demographic groups and socioeconomic factors, such as income and insurance, multivariate analyses were conducted for a small number of measures.^xi These analyses generated adjusted percentages that control for multiple factors simultaneously. For example, the percentages of breast cancer screening are compared for different racial and ethnic groups after adjusting for differences in the distributions of income, education, insurance, age, gender, and geographic location. To account for Medicare, the analyses were done separately for people under age 65 and age 65 years and over.

Finally, to ensure that the findings were not biased by the sequence in which each factor was entered into the analysis, 12 separate analyses were done for each of the 12 measures. Adjusted percentages are used to quantify the magnitude of disparities after controlling for a number of confounding factors. Results of multivariate analyses are shown for two quality measures (breast cancer screenings and recommended care for diabetes) and two access measures (percentage uninsured and percentage with specific source of ongoing care).

Quantifying Disparities

In the Highlights and in Chapter 4, Priority Populations, the extent of disparities across the core measures is summarized for Blacks, Hispanics, Asians, NHOPIs, AI/ANs, and poor populations.Racial, ethnic, and socioeconomic groups are compared with a designated reference group for each core measure. Each group could receive care that is worse than, about the same as, or better than the reference group. For each group, the percentages of measures for which the group received worse care, similar care, or better care were calculated.

Health care utilization measures are difficult to interpret and were excluded when summarizing disparities in access to care.^xii In Chapter 4, Priority Populations, which presents information on each population separately, all core measures are used when summarizing trends in disparities for each group. However, in the Highlights, where multiple groups are presented side by side, only core measures with estimates for all racial and ethnic groups over time are used, to facilitate comparisons across groups. An exception is made for income comparisons of quality measures because much less information is available for income groups than for racial and ethnic groups.

Beginning with the 2005 NHDR, rates relative to standard reference groups are used to quantify the magnitude of disparities and to identify the largest disparities specific groups faced. For each group, the group rate was divided by the reference group rate to calculate the relative rate for each core measure. Relative rates of selected core measures are presented in the Highlights section of this report. 

Changes to the Measure Set

The measure sets used in the 2008 NHDR and NHQR have been improved in several ways for 2009. As in previous years, a handful of measures were modified to reflect changing standards of care or improved information about care. Although no core measures were added, some noncore measures are being presented in the reports for the first time in 2009.

Modifications to Existing Composite Measures

The changes applied to existing measures this year were for individual component measures that make up composite measures. The changes affect the comparability of data over time to varying degrees for each measure. Beginning in the 2007 reports, the following core composite measures of effectiveness and patient safety underwent modifications:

• Recommended hospital care received by Medicare patients with acute myocardial infarction composite. The individual measure on use of angiotensin-converting enzyme (ACE) inhibitors in patients with left ventricular systolic dysfunction was changed to also include angiotensin receptor blockers (ARBs) as an acceptable alternative.
• Recommended hospital care received by Medicare patients with heart failure. The individual measure on use of ACE inhibitors in patients with left ventricular systolic dysfunction was changed to also include ARBs as an acceptable alternative.
• Recommended hospital care received by Medicare patients with pneumonia. Two component measures underwent revision:
  • The individual measure of appropriate antibiotic selection for community-acquired pneumonia was changed to exclude patients with health care-associated pneumonia from the denominator used in the calculation.
  • The individual measure for the collection of samples for blood culture within 24 hours of hospital arrival was changed so that only those patients who were admitted to the intensive care unit within 24 hours of hospital arrival are included in the denominator.
• Postoperative care. The individual measure for postoperative urinary tract infection was refined to include only patients with catheter-associated urinary tract infections.

New Noncore Measures

The Interagency Work Group identifies noncore measures to provide additional information to fill a specific data gap in a particular topic area. Each year, the NHDR features noncore measures in special focus sections of the report. The following new noncore measure is included in the 2009 NHDR to fill an identified gap:

• One measure of workforce diversity from the American Community Survey: U.S. dentistry professionals by race and ethnicity.

Measure revisions were proposed and reviewed in meetings of the Interagency Work Group for the NHDR, which includes representation from across HHS.

Databases Used in the 2009 Reports

Table 1.5 lists the databases used in the 2009 reports.

Table 1.5. Databases used in the 2009 reports (new databases in italics)

^a This file is designed to provide national estimates of disparities in the AHRQ Quality Indicators using weighted records from a sample of hospitals from the following 23 States: Arizona, Arkansas, California, Colorado, Connecticut, Florida, Georgia, Hawaii, Kansas, Maryland, Massachusetts, Michigan, Missouri, New Hampshire, New Jersey, New York, Oklahoma, Rhode Island, South Carolina, Tennessee, Texas, Utah, Vermont, Virginia, and Wisconsin.

Individuals With Disabilities

The Interagency Work Group Subcommittee on Disability Statistics convened to develop a broad definition of disabilities that can be applied across different national data sources to obtain data on the quality of care for adults with disabilities. Beginning with the 2007 NHDR, AHRQ has used a broad, inclusive measure of disability. This measure is intended to be consistent with statutory definitions of disability, such as the first criterion of the Americans With Disabilities Act of 1990, 42 U.S.C. §§ 12181 et seq. (i.e., having a physical or mental impairment that substantially limits one or more major life activities) and Federal program definitions based on the Americans With Disabilities Act.

For the purpose of the NHDR, people with disabilities are those with physical, sensory, and/or mental health conditions who also have an associated decrease in functioning in such day-to-day activities as bathing, walking, doing everyday chores, and/or engaging in work or social activities. In displaying the data on disability, paired measures are shown to preserve the qualitative aspects of the data:

• Limitations in basic activities represent problems with mobility and other basic functioning at the person level.
• Limitations in complex activities represent constraints encountered when people, in interaction with their environment, attempt to participate in community life.

The use of the subcommittee's recommendation of these paired measures of basic and complex activity limitations is conceptually similar to the way others have divided disability. It is also consistent with the International Classification of Functioning, Disability, and Health separation of activities and participation domains. These two categories are not mutually exclusive; people may have limitations in basic activities and limitations in complex activities. Further information regarding the definition and methods can be found in the Individuals With Disabilities and Special Health Care Needs section in Chapter 4, Priority Populations.

Reference

1. National Center for Health Statistics. Health, United States, 2007: with chartbook on trends in the health of Americans. Hyattsville, MD: Centers for Disease Control and Prevention; 2007. Available at: http://www.cdc.gov/nchs/data/hus/hus07.pdf [Plugin Software Help]. Accessed on August 27, 2009.

ⁱ Socioeconomic disparities include differences in education and income levels.
ⁱⁱ Due to scarcity of health care data for this population, this report has supplemented national estimates (which often do not meet statistical reliability criteria for reporting) with State-level data. More information can be found in Chapter 4.
ⁱⁱⁱ NHDR data can be accessed through NHQRDRnet, an online tool that provides Internet users with an opportunity to specify dimensions of analysis and produce data tables. NHQRDRnet is available through the AHRQ Web site at http://nhqrnet.ahrq.gov.
^iv Refer to Chapter 1, Introduction and Methods, in the 2006 NHQR for more detailed information about these and other methods that are used to calculate composite measures used in the reports. Accessible at http://archive.ahrq.gov/qual/nhqr06/report/Chap1.htm
^v Asian includes the former category of Asian or Pacific Islander prior to Office of Management and Budget guidelines when information is not collected separately for each group
^vi Not all data sources used in the NHDR collect data by race and ethnicity separately (e.g., allowing for comparisons of Blacks with Whites and Hispanics with non-Hispanic Whites). In such cases, comparisons are made by combined racial/ethnic categories (e.g., comparing non-Hispanic Blacks and Hispanics with non-Hispanic Whites).
^vii Throughout this report, poor is defined as having family income less than 100% of the Federal poverty level; near poor, between 100% and 199%; middle income, between 200% and 399%; and high income, 400% or more of the Federal poverty level. These are based on U.S. Census poverty thresholds for each data year, which are used for statistical purposes, unlike HHS poverty guidelines used for programmatic purposes.
^viii The measures are obese adults given advice about exercise and individuals having a usual primary care provider.
^ix Criteria for importance are that the difference is statistically significant at the alpha=0.05 level, two-tailed test, and that the relative difference is at least 10% different from the reference group when framed positively as a favorable outcome or negatively as an adverse outcome.
^x The geometric rate of change assumes that a measure increases or decreases at the same rate during each year between two time periods. It is calculated using the following formula: [(V_Y/V_Z)^1/N-1] = 100, where V_Y is the most recent year's value, V_Z is the most distant year's value, and N is the number of years in the interval. Refer to the entry for Average Annual Rate of Change in Appendix II, Definitions and Methods, Health, United States, 2007 (available at http://www.cdc.gov/nchs/hus.htm).
^xi Multivariate analyses were conducted for the following measures for which data were available: breast cancer screening, children who did not have patient-centered care, children who received advice about healthy eating, children who sometimes or never got care for illness or injury as soon as wanted, children ages 3-6 who ever had a vision check, adults with a dental visit in the past year, diabetes patients who received recommended care, adults ages 18-64 uninsured all year, adults who did not have patient-centered care, adults with a usual primary care provider, adult smokers with advice to quit smoking, and adults who sometimes or never got care for illness or injury as soon as wanted.
^xii Interpreting health care utilization data is more complex than analyzing data on patient perceptions of access to care. Along with access to care, health care utilization is strongly affected by health care need and patient preferences and values. In addition, greater use of services does not necessarily indicate better care. In fact, high use of some inpatient services may reflect impaired access to outpatient services. For these reasons, measures of health care utilization are excluded from summaries of access to health care.

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