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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 status (SES), this directive includes a charge to examine disparities in "priority populations"—groups with unique health care needs or issues that require special focus. The National Healthcare Disparities Report (NHDR) was designed and produced by AHRQ, with support from the Department of Health and Human Services (HHS) and private sector partners, to respond to this legislative mandate.

The first NHDR, released in 2003, 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 2007 NHDR represents the fifth 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. More specifically, it attempts to go beyond previous NHDRs by clearly reporting on trends in health care disparities and the degree to which health care disparities for racial/ethnic minorities and poor populations have lessened.

This chapter summarizes the methodological approaches taken by AHRQ in producing the 2007 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 Asian subpopulations and expanded material on Hispanic subpopulations.
  • New supplemental measures on HIV testing.
  • New supplemental measures on health literacy.
  • Expanded focus on individuals with disabilities.
  • Trend analyses that focus on how disparities between groups have changed over time.

As in previous years, the 2007 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. In addition, a subgroup on disabilities was convened to address issues surrounding the continued refinement of definitions of persons with disabilities and the presentation of data on quality of and access to care for adults with disabilities.


i Socioeconomic disparities include differences in education and income levels.


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How This Report Is Organized

The basic structure of the 2007 NHDR includes the following chapters:

Appendixes include:

  • Appendix A: Data Sources provides information about each database analyzed for the NHDR, including data type, sample design, and primary content.
  • Appendix B: Detailed Methods provides detailed methods for selected databases analyzed for the NHDR.
  • Appendix C: 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.
  • Appendix D: 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.ii When data are available:
    • Race tables and ethnicity tables are stratified by age, gender, residence location, and one or more socioeconomic variables (i.e., household income, education, insurance, and/or area income).
    • Socioeconomic tables are stratified by age, gender, residence location, race, and ethnicity.

ii NHDR data can now be accessed through NHDRnet, an online tool that provides Internet users with an opportunity to specify dimensions of analysis and produce data tables. NHDRnet is available through the AHRQ Web site at http://nhdrnet.ahrq.gov/nhdr/jsp/nhdr.jsp.


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Presentation of the Measure Set

Core and Composite Measures

Core measures. For the 2005 NHDR and NHQR, the Interagency Work Group was convened to select a group of measures from the full measure sets on which the reports would present findings each year. In 2006, the work group made additional changes to the core measure set. For some topics, the group favored 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
Reported in 2006 NHDR and NHQR* Reported in 2007 NHDR and NHQR
Colorectal cancer screening Breast cancer screening
Late stage colorectal cancers Late stage breast cancers
Colorectal cancer mortality Breast cancer mortality
Children who received advice about healthy eating Children who received advice about exercise
Children who had a vision check Children who had dental care

*The measures listed in this column will be reported again in the 2008 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). Both types of measures are not reported for all conditions due to data limitations. For example, data on HIV care are suboptimal; hence, no HIV process measures are included as core measures. In addition, not all core measures are included in trending analysis because 2 or more years of data are not available.

Composite measures. Policymakers and others have voiced their support for composite measures because they can be used to facilitate understanding of information from many different measures. The effort to develop new composites is ongoing, and in 2006, a number of new composite measures were added.iii Composite measures, which now make up about 20% of the core measures, are listed in Table 1.3.

Composite measures in the NHDR and NHQR are created based on two different models—appropriateness model or opportunities model. 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.


iii Go 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.


Presentation. The 2007 NHDR and its companion NHQR continue to be formatted as chartbooks. The 2007 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 2007 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,iv Native Hawaiians or Other Pacific Islanders (NHOPIs), American Indians and Alaska Natives (AI/ANs), and people of more than one race compared with Whites.
  • Ethnicity—Hispanics compared with non-Hispanic Whites.v
  • Income—Poor, near poor, and middle income people compared with high income people.vi
  • Education—People with less than a high school education and high school graduates compared with people with any college education.

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 SES 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 below.)vii

New this year is an attempt to characterize whether gaps between priority populations and the reference group are growing larger, getting smaller, or have not changed. This is done as 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.

As in last year's report, findings presented in the text meet report criteria for importance;viii 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.


iv "Asian" includes "Asian or Pacific Islander" when information is not collected separately for each group.

v Not all data sources used in the NHDR collect data by race and ethnicity separately (i.e., allowing for comparisons of Blacks with Whites and Hispanics with non-Hispanic Whites). When this is the case, comparisons are made by combined racial/ethnic categories (i.e., comparing non-Hispanic Blacks and Hispanics with non-Hispanic Whites).

vi 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.

vii The measures are obese adults given advice about exercise and individuals having a usual primary care provider.

viii 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.


In addition, effectiveness measures for each condition or care setting area are organized further into categories that reflect the patient's need for preventive care, treatment of acute illness, and 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 2007 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 2007 NHDR and NHQR.ix

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 with alpha=0.05.
  • Second, the magnitude of average annual rate of change must be at least 1% per year when the measures are framed as a favorable outcome or as an adverse outcome.

Only changes over time that meet these two criteria are discussed in the 2007 reports. They are categorized as the following:

  • 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 are identified as improving disparities.
  • Core measures for which the relative differences are becoming larger at a rate of more than 1% per year are identified as worsening disparities.
  • Changes of greater than 5% per year are also differentiated from changes of 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 "Native Hawaiian or Other Pacific Islander." In addition, individuals could report more than one race. This results in underestimates for the "American Indian and Alaska Native" category, since a large proportion of this group identify as mixed race. In contrast, effects on estimates for Whites, Blacks, and Hispanics were proportionately much smaller. Consequently, the 2007 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.


ix 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: [(VY/VZ)1/N−1] × 100, where VY is the most recent year's value, VZ is the most distant year's value, and N is the number of years in the interval.


Bivariate and multivariate analyses. Bivariate analyses are included for some measures for which data are available to examine the interrelationship between race/ethnicity and SES in Chapter 3, Access to Health Care, as well as in the section on low income groups in Chapter 4, Priority Populations. This year, the NHDR also examines the question of the interrelationship between insurance status and income for quality of care in more depth for some selected measures through the use of bivariate analyses in Chapter 4, Priority Populations.

In multivariate models, estimates for a measure are controlled for multiple factors, including race, ethnicity, income, education, insurance, age, gender, and residence location, to show the extent to which these factors affect an outcome. In order 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 odds ratios are shown to quantify the relative magnitude of disparities after controlling for a number of confounding factors. Two selected measures—one quality measure (obese adults given advice about exercise) and one access measure (persons who have a usual primary care provider)—were selected to conduct multivariate analyses.

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.x 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 the groups. As noted above, 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 faced by specific groups. 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.


x 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.


Table 1.2. 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.)
Section Process measures Outcome measures
Effectiveness—Cancer Women age 40 and over who reported they had a mammogram within the past 2 years Rate of breast cancer incidence per 100,000 women age 40 and over diagnosed at advanced stage
Cancer deaths per 100,000 women per year for breast cancer
Effectiveness—Diabetes • Composite: Adults age 40 and over with diabetes who had all 3 recommended services for diabetes in the past year (at least 1 hemoglobin A1c measurement, a retinal eye examination, and a foot examination) • Hospital admissions for lower extremity amputation in patients with diabetes per 100,000 population
Effectiveness—End Stage Renal Disease Dialysis patients registered on waiting list for transplantation Hemodialysis patients with adequate dialysis (urea reduction ratio 65% or greater)
Effectiveness—Heart Disease Composite: Patients with acute myocardial infarction (AMI) who received recommended hospital care for AMI (administered aspirin and beta blocker within 24 hours of admission, prescribed aspirin and beta blocker at discharge, and given smoking cessation counseling while hospitalized)a
Composite: Heart failure patients who received recommended hospital care for heart failure (evaluation of left ventricular ejection fraction and prescribed ACE inhibitor or ARB at discharge, if indicated, for left ventricular systolic dysfunction)
• Current smokers age 18 and over receiving advice to quit smoking
• Adults who were obese who were given advice about exercise
• Acute myocardial infarction (AMI) mortality rate (number of deaths per 1,000 discharges for AMI)
Effectiveness—HIV and AIDS   New AIDS cases per 100,000 population age 13 and over
Effectiveness—Maternal and Child Health Pregnant women receiving prenatal care in first trimester
Children 19-35 months who received all recommended vaccines
• Children ages 2-17 who received advice from a doctor or other health provider about healthy eating
• Children ages 2-17 who had a dental visit in the past year
Infant mortality per 1,000 live births, birthweight <1,500 grams
• Hospital admissions for pediatric gastroenteritis per 100,000 population ages 4 months-17 years
Effectiveness—Mental Health and Substance Abuse • Adults age 18 and over with major depressive episode in the past year who received treatment for the depression in the past year
• Persons age 12 and over who needed treatment for any illicit drug use and who received such treatment at a specialty facility in the past year
• Deaths due to suicide per 100,000 population
Effectiveness—Respiratory Diseases Adults age 65 and over who ever received pneumococcal vaccination
Composite: Pneumonia patients who received recommended hospital care for pneumonia (had blood cultures collected before antibiotics administered, received the initial antibiotic dose within 4 hours of hospital arrival and consistent with current recommendations, and received screening for influenza and pneumococcal disease vaccination status and vaccination, if indicated)b
Tuberculosis patients who complete a curative course of treatment within 12 months of initiation of treatment
• Hospital admissions for pediatric asthma per 100,000 population ages 2-17 years
Effectiveness—Nursing Home, Home Health, and Hospice Care Long-stay nursing home residents who were physically restrained High-risk long-stay nursing home residents who have pressure sores
Low-risk long-stay nursing home residents who have pressure sores
Home health care patients who get better at walking or moving around
Home health care patients who had to be admitted to the hospital
Patient Safety Composite: Adult Medicare patients having surgery who received appropriate timing of antibiotics
• Percent of community-dwelling adults age 65 and over who had at least 1 prescription (from a list of 33 medications) that is potentially inappropriate for the elderly
• Composite: Adult surgery patients with postoperative complications (postoperative pneumonia, catheter-associated urinary tract infectionc, or venous thromboembolic events)
• Bloodstream infections or mechanical adverse events associated with central venous catheters
• Deaths per 1,000 discharges with complications potentially resulting from care (failure to rescue)
Timeliness   • Adults who can sometimes or never get care for illness or injury as soon as wanted
Patient Centeredness Composite: Ambulatory patients (adults) who reported poor communication with health providers (whose health providers sometimes or never listened carefully, explained things clearly, respected what they had to say, or spent enough time with them)
• Composite: Ambulatory patients (children) whose parents reported poor communication with health providers (whose health providers sometimes or never listened carefully, explained things clearly, respected what their parents had to say, or spent enough time with them)
 
Access Persons under age 65 with health insurance
Persons under age 65 who were uninsured all year
Persons who have a specific source of ongoing care
Persons who have a usual primary care provider
People who were unable or delayed in receiving needed medical care, dental care, or prescription medications
People without a usual source of care who indicate a financial or insurance reason for not having a source of care
 

a 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.

b Appropriate antibiotic selection was changed to exclude patients with health-care-associated pneumonia from the denominator used in the calculation. 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.

c The individual measure for postoperative urinary tract infection was refined to include only patients with catheter-associated urinary tract infections.

Note: For two core measures, new data were not available for the 2007 NHDR; thus these measures are excluded from summary analyses. The measures are: (1) visits where antibiotic was prescribed for diagnosis of a common cold and (2) patients who left the emergency department without being seen.

Table 1.3. Composite measures in the 2007 NHQR and NHDR (updated measures in italics)
Composite measure Individual measures forming composite
Receipt of three recommended diabetes services • Adults age 40 and over with diabetes who had a hemoglobin A1c measurement at least once in the past year
• Adults age 40 and over with diabetes who had a retinal eye examination in the past year
• Adults age 40 and over with diabetes who had a foot examination in the past year
Childhood immunization • Children 19-35 months who received 4 doses of diphtheria-pertussis-tetanus vaccine
• Children 19-35 months who received at least 3 doses of polio vaccine
• Children 19-35 months who received at least 1 dose of measles-mumps-rubella vaccine
• Children 19-35 months who received 3 doses of Haemophilus influenzae type B vaccine
• Children 19-35 months who received 3 doses of hepatitis B vaccine
Recommended hospital care for heart attacka • Acute myocardial infarction (AMI) patients administered aspirin within 24 hours of admission
• AMI patients with aspirin prescribed at discharge
• AMI patients administered beta blocker within 24 hours of admission
• AMI patients with beta blocker prescribed at discharge
• AMI patients with left ventricular systolic dysfunction prescribed ACE inhibitor or ARB at discharge
• Current smokers age 18 and over receiving advice to quit smoking
Recommended hospital care for heart failurea • Heart failure patients who received evaluation of left ventricular ejection fraction
• Heart failure patients with left ventricular systolic dysfunction prescribed ACE inhibitor or ARB at discharge
Recommended hospital care for pneumoniab • Patients with pneumonia who received the initial antibiotic dose within 4 hours of hospital arrival
• Patients with pneumonia who received the initial antibiotic consistent with current recommendations
• Patients with pneumonia who had blood cultures collected before antibiotics were administered
• Patients with pneumonia who received influenza screening or vaccination
• Patients with pneumonia who received pneumococcal screening or vaccination
Timing of antibiotics to prevent postoperative wound infection • Adult Medicare patients having surgery who receive prophylactic antibiotics within 1 hour prior to surgical incision
• Adult Medicare patients having surgery who have prophylactic antibiotics discontinued within 24 hours after surgery end time
Patient experience of care • Adults who had a doctor's office or clinic visit in the last 12 months whose providers sometimes or never listened carefully to them
• Adults who had a doctor's office or clinic visit in the last 12 months whose providers sometimes or never explained things in a way they could understand
• Adults who had a doctor's office or clinic visit in the last 12 months whose providers sometimes or never showed respect for what they had to say
• Adults who had a doctor's office or clinic visit in the last 12 months whose providers sometimes or never spent enough time with them
• Children who had a doctor's office or clinic visit in the last 12 months whose parents report that their child's providers sometimes or never listened carefully to them
• Children who had a doctor's office or clinic visit in the last 12 months whose parents report that their child's providers sometimes or never explained things in a way they could understand
• Children who had a doctor's office or clinic visit in the last 12 months whose parents report that their child's providers sometimes or never showed respect for what they had to say
• Children who had a doctor's office or clinic visit in the last 12 months whose parents report that their child's providers sometimes or never spent enough time with them
Postoperative complicationsc • Adult surgery patients with postoperative pneumonia events
• Adult surgery patients with catheter-associated urinary tract infection
• Adult surgery patients with postoperative venous thromboembolic events
Complications of central venous catheters • Bloodstream infections associated with central venous catheters
• Mechanical adverse events associated with central venous catheters

a 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.

b Appropriate antibiotic selection was changed to exclude patients with health-care-associated pneumonia from the denominator used in the calculation. 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.

c The individual measure for postoperative urinary tract infection was refined to include only patients with catheter-associated urinary tract infections.

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Changes to the Measure Set

The measure sets used in the 2007 NHDR and NHQR have been improved in several ways. A handful of measures were modified to reflect changing standards of care or improved information about care. Although no additional core measures were added, some supplemental measures are being presented in the reports for the first time in 2007.

Modifications of 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. This year 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 supplemental measures. Supplemental measures are measures identified by the Interagency Work Group to provide additional information in the NHDR to fill a specific data gap in a particular topic area. Each year, the NHDR features supplemental measures in special focus sections of the report. The following new supplemental measures have been included in the 2007 NHDR to fill identified gaps:

  • Three measures of HIV testing from the Centers for Disease Control and Prevention, National Center for Health Statistics (NCHS), National Survey of Family Growth (NSFG):
    • Women ages 15-44 who completed a pregnancy in the last 12 months and had an HIV test as part of prenatal care.
    • People ages 15-44 who ever had an HIV test outside of blood donation in the last 12 months.
    • People ages 15-44 with any HIV risk behaviors in the last 12 months who had an HIV test outside of blood donation in the last 12 months.
  • One measure of workforce diversity from the American Community Survey (ACS) and the National Sample Survey of Registered Nurses:
    • U.S. nurses by race and ethnicity.
  • One measure of health literacy from the Health Literacy Component (HLC) of the National Assessment of Adult Literacy:
    • Percent of adults in each literacy level (below basic, basic, intermediate, proficient).

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

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Other Improvements in This Report

A number of improvements in the quality and accessibility of the NHDR are made each year. Improvements include the addition of new data sources, additional analyses of Asian and Hispanic subpopulations, an enhanced discussion of individuals with disabilities, and trend analyses refocused on changes over time in disparities between groups.

New Data Sources

NHDR data sources include surveys of individuals and health care facilities extracted from surveillance, vital statistics, and health care organization data systems (Table 1.4). Standardized suppression criteria were applied to all databases to support reliable estimates.xi New data added this year come from the following sources (in order of appearance in the NHDR):


xi Estimates based on sample size fewer than 30 or with relative standard error greater than 30% are considered unreliable and suppressed. Databases with more conservative suppression criteria retain their own standards.


  • National Survey of Family Growth. The NSFG gathers information on family life, marriage and divorce, pregnancy, infertility, use of contraception, and men's and women's reproductive health. Survey data are collected by NCHS and the results are used by HHS and others to plan health services and health education programs and to complete statistical studies of families, fertility, and reproductive health. Data about HIV testing prevalence from the NSFG are included in the 2007 NHDR.
  • National Sample Survey of Registered Nurses. This survey is administered by the Bureau of Health Professions (BHP) Evaluation and Analysis Branch of the Health Resources and Services Administration (HRSA) in HHS. It examines the number, characteristics, and geographic distribution of nurses at the national and State level to ensure an adequate supply of qualified nursing personnel.
  • American Community Survey. The ACS is used in the 2007 NHDR to provide population estimates for workforce diversity assessments. This survey is a new nationwide survey administered by the U.S. Census Bureau and is designed to provide more up-to-date information about trends in the U.S. population at the local level. The ACS collects information such as age, race, income, commute time to work, home value, veteran status, and other important data from U.S. households every year.
  • Health Literacy Component of the National Assessment of Adult Literacy. The HLC assesses responses to health-related tasks presented in written form. The HLC tasks require familiarity with health-related words, experience with written materials, such as drug labels and health insurance forms, or knowledge of how the health care system works.
  • California Health Interview Survey (CHIS). This telephone survey of adults, adolescents, and children from all parts of California is conducted every 2 years. Although the NHDR typically includes only data sets that can provide nationally representative estimates from its samples, the CHIS collects unique information on certain racial and ethnic minorities highly prevalent in California. In particular, the CHIS 2005, used in this year's NHDR, collected information on quality and access for Hispanic and Asian subpopulations based on a sample of more than 45,000 households. Survey data from CHIS on English proficiency and place of birth as they relate to quality outcomes and access to care are also presented in the 2007 NHDR.
Table 1.4. Databases used in the 2007 reports (new databases in italics)
Survey data collected from populations:
• AHRQ, Medical Expenditure Panel Survey, 2002-2004
• CAHPS® Hospital Survey, 2007
California Health Interview Survey, 2001-2005
• Centers for Disease Control and Prevention (CDC), Behavioral Risk Factor Surveillance System, 2001-2005
• CDC-NCHS, National Health and Nutrition Examination Survey, 1999-2004
• CDC-NCHS, National Health Interview Survey, 1998-2005
CDC-NCHS, National Survey of Family Growth, 2002
• CDC-NCHS/National Immunization Program, National Immunization Survey, 1998-2005
• Centers for Medicare & Medicaid Services (CMS), Medicare Current Beneficiary Survey, 1998-2003
National Center for Education Statistics, National Assessment of Adult Literacy, Health Literacy Component, 2003
• National Hospice and Palliative Care Organization, Family Evaluation of Hospice Care, 2005
• Substance Abuse and Mental Health Services Administration (SAMHSA), National Survey on Drug Use and Health, 2002-2005
U.S. Census Bureau, American Community Survey, 2004
Data collected from samples of health care facilities and providers:
American Cancer Society and American College of Surgeons, National Cancer Data Base, 1999-2004
• CDC-NCHS, National Ambulatory Medical Care Survey, 1997-2004
• CDC-NCHS, National Hospital Ambulatory Medical Care Survey-Emergency Department, 1997-2004
• CDC-NCHS, National Hospital Ambulatory Medical Care Survey-Outpatient Department, 1997-2004
• CDC-NCHS, National Hospital Discharge Survey, 1998-2005
CDC-NCHS National Nursing Home Survey, 2004
• CMS, End Stage Renal Disease Clinical Performance Measures Project, 2001-2005
Health Resources and Services Administration-Bureau of Health Professions, National Sample Survey of Registered Nurses, 2004
Data extracted from data systems of health care organizations:
• AHRQ, Healthcare Cost and Utilization Project (HCUP) State Inpatient Databases disparities analysis file,* 2001-2004
• CMS, Home Health Outcomes and Assessment Information Set, 2002-2005
• CMS, Hospital Compare, 2006
• CMS, Medicare Patient Safety Monitoring System, 2003-2005
• CMS, Nursing Home Minimum Data Set, 2002-2005
• CMS, Quality Improvement Organization program, Hospital Quality Alliance measures, 2000-2004
• HIV Research Network data, 2001-2003
• Indian Health Service, National Patient Information Reporting System, 2002-2004
• National Committee for Quality Assurance, Health Plan Employer Data and Information Set (HEDIS®), 2001-2005
• National Institutes of Health (NIH), United States Renal Data System, 1998-2003
• SAMHSA, Treatment Episode Data Set, 2002-2004
Data from surveillance and vital statistics systems:
• CDC, National Program of Cancer Registries, 2000-2004
• CDC-National Center for HIV, STD, and TB Prevention, HIV/AIDS Surveillance System, 1998-2005
• CDC-National Center for HIV, STD, and TB Prevention, TB Surveillance System, 1999-2003
• CDC-NCHS, National Vital Statistics System, 1999-2004
• NIH-National Cancer Institute, Surveillance, Epidemiology, and End Results (SEER) program, 1992-2004

* 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 22 States: Arizona, California, Colorado, Connecticut, Florida, Georgia, Hawaii, Kansas, Maryland, Massachusetts, Michigan, Missouri, New Jersey, New York, Pennsylvania, Rhode Island, South Carolina, Tennessee, Texas, Vermont, Virginia, and Wisconsin.

Note: Measures from the National Nursing Home Survey and the National Cancer Data Base are used only in the 2007 NHQR. For details on these surveys, go to Chapter 1, Introduction and Methods, in the 2007 NHQR.

Expanded Analysis of Trends in Disparities

Starting with the 2007 NHDR, an additional dimension of trends is emphasized in the reports. In previous years the NHDR included discussion of change over time for each population from baseline to most recent data year, where available, and also reported separately on statistically significant differences between a comparison group and reference group. The 2007 NHDR combines the discussion of change over time and differences between groups by focusing on the change over time in the gap or difference between groups. Thus, the NHDR can now show not only where disparities exist in health care quality and access to health care, but also how disparities have changed over time.

The criteria for reporting on change over time in the gap or disparity between comparison group and reference group is as follows:

  • There is a statistically significant difference between the estimate for the baseline year and the most recent data year for at least one group.
  • There is a statistically significant difference between a comparison group and reference group at baseline year, at most recent data year, or at both baseline year and most recent data year.

The change in the gap is reported if these criteria are met. The change is reported as increased if the absolute difference of the gap between the comparison group and reference group in the most recent data year was greater than the gap in the baseline year. The change is reported as decreased if the absolute difference in the gap between the comparison group and reference group in the most recent data year was less than the gap in the baseline year. Change is not reported if there was no change in either comparison group or reference group, if both the reference group and comparison group show significant differences between the baseline year and the most recent data year, or if data were not available for more than one data year.

No statistical test was performed for the difference from the baseline year to the most recent data year in the difference between the comparison group and reference group. Since most differences are relatively small, performing an additional statistical test would eliminate most reports of change in disparities.

The NHDR continues to report statistically significant differences between the comparison group and reference group where data are available for the most recent data year. Since the NHDR now contains estimates for several data years for most of the measures, for simplification in reporting on disparities, only the most recent data year is discussed.xii

Asian and Hispanic Subpopulations

As with all U.S. populations, racial and ethnic minority groups that are the focus of the NHDR are highly heterogeneous. Data are typically not available to examine different racial and ethnic groups in greater detail. The California Health Interview Survey is an exception. The 2007 NHDR features updated data from this survey for Hispanic and Asian subpopulations. The 2007 NHDR also continues to show health care information from the Medical Expenditure Panel Survey differentiating Hispanics of Mexican, Central or South American, Puerto Rican, and Cuban descent. These analyses are presented in the section on racial and ethnic minorities in Chapter 4, Priority Populations.


xii For estimates from prior years, go to Appendix D: Data Tables for previous releases of the NHDR.


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 people with disabilities. For the 2007 NHDR, AHRQ is using a broad, inclusive measure of disability that is intended to be consistent with statutory definitions of disability, such as the first criterion of the 1990 Americans with Disabilities Act (i.e., having a physical or mental impairment that substantially limits one or more major life activities) and other Federal programs' definitions of disability. 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, and is consistent with the International Classification of Functioning, Disability and Health (ICF) separation of activities and participation domains. These two categories are not mutually exclusive; persons may have both 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.

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Reference

1. National Center for Health Statistics. Health, United States, 2006. Available at http://www.cdc.gov/nchs/hus.htm. Accessed November 1, 2007.

AHRQ Advancing Excellence in Health Care