The National Health Care Survey

People use health care services for many reasons: to cure illnesses and health conditions, to mend breaks and tears, to prevent or delay future health care problems, to reduce pain and increase quality of life, and sometimes merely to obtain information about their health status and prognosis. Health care utilization can be appropriate or inappropriate, of high or low quality, expensive orinexpensive. The study of trends in health care utilization provides important information on thesephenomena and may spotlight areas that may warrant future indepth studies because of potentialdisparities in access to, or quality of, care. Trends in utilization may also be used as the basis forprojecting future health care needs, to forecast future health care expenditures, or as the basis forprojecting increased personnel training or supply initiatives.

The health care delivery system of today has undergone tremendous change, even over the relatively short period of the past decade. New and emerging technologies, including drugs, devices, procedures, tests, and imaging machinery, have changed patterns of care and sites where care is provided. The growth in ambulatory surgery has been influenced by improvements in anesthesia and analgesia and by the development of noninvasive or minimally invasive techniques. Procedures that formerly required a few weeks of convalescence now require only a few days. New drugs can cure or lengthen the course of disease, although often at increased cost or increased utilization of medical practitioners needed to prescribe and monitor the effects of the medications. Over the past decade, both public and private organizations have made great strides in identifying causes of disease and disability, discovering treatments and cures, and working with practitioners to educate the public about how to reduce the incidence and prevalence of major diseases and the functional limitations and discomfort they may cause. Clinical practice guidelines have been created and disseminated to influence providers to follow recommended practices. Public education campaigns urge consumers to comply with behavioral recommendations (e.g., exercise and lose weight) and treatment regimens (e.g., take your medications) that may help to prevent or control diseases and their consequences.

Health care utilization also has evolved as the population’s need for care has changed over time. Some factors that influence need include aging, sociodemographic population shifts, and changes in the prevalence and incidence of different diseases. As the prevalence of chronic conditions increases, for example, residential and community-based health-related services have emerged that are designed to minimize loss of function and to keep people out of institutional settings. The growth of managed care and payment mechanisms employed by insurers and other payers in an attempt to control the rate of health care spending has also had a major impact on health care utilization. Efforts by employers to increase managed care enrollment, as well as major Medicare and Medicaid cost containment efforts such as the Prospective Payment System for hospitals and the Resource Based Relative Value Scale for physician payment, created incentives to shift sites where services are provided (3,4). They also created incentives to provide services differently; for example, the increase in capitated payment and use of gatekeepers has been associated with a changing mix of primary care and specialty care (see “Visits to Primary Care and Specialty Physicians”) . Numerous other factors also influence the type and amount of health care utilization that is provided in the United States (see “Forces that Affect Overall Health Care Utilization”)  The Centers for Disease Control and Prevention, National Center for Health Statistics (NCHS), Division of Health Care Statistics is charged with conducting surveys of health care providers and facilities. These surveys track the number of encounters these entities provide and describe characteristics of those who seek care, the content of the encounters, and characteristics of providers. It accomplishes this mission in part by fielding a family of surveys that are collectively called the National Health Care Survey (NHCS). The NHCS produces important information on hospitalizations and surgeries, ambulatory physician visits, and long-term care use in the United States. It can be used to compare services received across different settings, to relate provider characteristics to patient utilization, to compare utilization rates among subpopulations, and, in general, to assess how the health care delivery system is being used and by whom.

Each NHCS component survey obtains information about the facilities that supply health care, the services rendered, and the characteristics of the patients served. Each survey is based on a multistage sampling design that includes health care facilities or providers and patient records. Data collected directly from the establishments and/or their records rather than from the patients, identify health care events—such as hospitalizations, surgeries, and long-term stays—and offer the most accurate and detailed data on diagnosis and treatment and institution characteristics. These data are used by policymakers, planners, researchers, and others in the health community for a variety of purposes, including monitoring changes in the use of health care resources, monitoring specific diseases, and examining the impact of new medical technologies.

The NHCS includes the following surveys:

• National Ambulatory Medical Care Survey (NAMCS)

• National Hospital Ambulatory Medical Care Survey (NHAMCS)

• National Hospital Discharge Survey (NHDS)

• National Survey of Ambulatory Surgery (NSAS)

• National Home and Hospice Care Survey (NHHCS)

• National Nursing Home Survey (NNHS)

These surveys are the major source of information in the United States on national trends in hospital length of stay and diagnoses associated with hospitalizations, ambulatory physician visits, nursing home stays, and home health and hospice care visits. Chart 1 shows component surveys of the NHCS, including typical sample sizes and years conducted. More detail on the component surveys and limitations of the data can be found in “Appendix I.” “Appendix II” presents definitions of terms used throughout this report. Only statistically significant differences between population groups or time trends are noted in the text, as well as on each chart. Computation of rates for hospital discharges and nursing homes, home health agencies, and hospices encounters use estimates of the civilian population of the United States based on the 1990 census and adjusted for underenumeration using the 1990 National Population Adjustment Matrix. Rates of physician, hospital outpatient, and hospital emergency department visits use the civilian noninstitutionalized population of the United States, also based on the 1990 census and adjusted for underenumeration. Although intercensal rates for the 1990s that incorporate data from the 2000 census are now available, they were not available at the time this report was compiled.

The first section of this book uses selected trend data to illustrate how—and to suggest some insights into why—health care utilization has changed over the past decade. The second section presents overall trends in health care, including use of inpatient hospital services; use of physician services in private offices, hospital outpatient departments, and emergency departments; and use of nursing home, home health care, and hospice care services. Trends for the entire U.S. population are presented first, followed by trends for specific age and race groups (black versus white populations); trends in utilization for specific conditions, drugs, and procedures; and trends in utilization associated with place of death.

In an attempt to show trends in utilization across the spectrum of care measured in our surveys, this book is not organized around specific surveys or specific populations (e.g., racial or age groups). Therefore, those interested in a particular type of care, such as home health care, will find charts illustrating trends in home health care by different population groups throughout the book. Similarly, overall trends in utilization by race appear throughout the book. When analyzing any of the trends in health care utilization presented in this book, it is critical to remember that all of the health care utilization data (doctor visits, emergency department or outpatient department visits, or discharges from hospitals, nursing homes, and home health agencies) from  the NHCS are derived from establishment- or provider-based surveys rather than population-based surveys. Thus, with the exception of daily census data from nursing homes and home health agencies, data from the surveys represent events, not persons. For example, persons who visited a physician more than once or were discharged from the hospital more than once during the period of data collection would be included multiple times in the list from which the sample was drawn. Utilization rates per capita (or per population) represent the magnitude of health care use by a particular population and can be compared across various population groups, but they cannot be used to examine the amount or type of care provided to individuals. In addition, examination of utilization trends for the entire U.S. population masks many underlying differences in utilization by subpopulation (e.g., race, age, or gender) and/or condition. Many of these underlying trends are presented in charts presented throughout this book.

This book is the first attempt to integrate data from all of the NHCS components into one publication that examines how health care utilization is changing across multiple settings. This book is neither exhaustive nor comprehensive in the utilization trend data it presents. Although it provides examples of overall trends in health care utilization, many other trends in diagnoses, conditions, and discharge disposition across population groups defined by different characteristics are not presented here. Many of these data are available from published reports, and a bibliography of publications using data from the NHCS is included in “Appendix III.” Hopefully, this book will serve as a starting point for examining how health care utilization is changing and what data gaps exist in our understanding of the evolving health care delivery system. root canal therapy or endodontic therapy root canal covington la