Research Findings #16: Patterns of Ambulatory Care Use: Changes from 1987 to 1996

The estimates in this report are based on the most recent data available from MEPS at the time the report was written. However, selected elements of MEPS data may be revised on the basis of additional analyses, which could result in slightly different estimates from those shown here. Please check the MEPS Web site for the most current file releases.

This report from the Agency for Healthcare Research and Quality (AHRQ) presents trends in the use of ambulatory care services by the U.S. population from 1987 to 1996. The authors examine the frequency with which people visit health care providers by the setting of care (office, hospital outpatient, or emergency room) and the reasons for visits (prevention, diagnosis or treatment, or emergency), paying special attention to differences between 1987 and 1996. They also examine variation in trends across several variables, including age, race, sex, urban versus rural residence, region, income, insurance status, and health status. Data come from AHRQ’s 1987 National Medical Expenditure Survey (NMES) and 1996 Medical Expenditure Panel Survey (MEPS). From 1987 to 1996, the percentage of visits that took place in outpatient hospital settings and emergency rooms decreased, with a commensurate increase in the percentage of total visits that took place in office-based settings. The percentage of ambulatory care visits that were for preventive reasons increased while the percentages for all other types of visits decreased.

Introduction

This report examines trends in the use of ambulatory care services by the U.S. civilian noninstitutionalized population from 1987 to 1996. In addition to the frequency with which people visit health care providers, we also examine whether there have been significant shifts over the 9-year period in the setting of care (office, hospital outpatient, or emergency room) and the reasons for visits (prevention, diagnosis or treatment, or emergency). We examine variation in trends across several variables, including age, race, sex, urban versus rural residence, region, income, insurance status, and health status. Our data come from the 1987 National Medical Expenditure Survey (NMES) and the 1996 Medical Expenditure Panel Survey (MEPS). Each provides information on one full year of health care use for the U.S. civilian noninstitutionalized population.

Only differences that were statistically significant at the 0.05 level are discussed in the text. A technical appendix provides tables of standard errors, detailed information on MEPS and NMES (including data collection methods, data editing, and variable creation), and definitions of the terms used in this report.

^top

Frequency of Visits

Table 1 presents the frequency of provider visits by different population characteristics. Overall, there was no substantial change from 1987 to 1996 in the percentage of people who had at least one ambulatory care visit. In both years, about three-quarters of the population had at least one visit. Furthermore, among those who had at least one ambulatory visit, there is little change in the average number of visits per person from 1987 to 1996: about seven in both years.

^top

Visit Setting

From 1987 to 1996, the percent of visits that took place in office-based settings increased.

As with outpatient departments, the percentage of ambulatory care visits that took place in hospital emergency rooms declined substantially for those with public insurance. In 1987, people under 65 with only public insurance had 8 percent of their ambulatory care visits in emergency rooms. By 1996, this figure had declined to 5 percent. Among the elderly with Medicare plus supplemental public insurance, the proportion of ambulatory visits to emergency rooms declined from 5 percent to 3 percent. Although not as large, there was also a significant decline in the percentage of visits that took place in emergency rooms for both elderly and non-elderly people with private insurance. It should be noted, however, that the proportion of ambulatory care visits to emergency rooms was much lower for privately insured individuals than for other groups at both time points. The proportion of visits that took place in emergency rooms did not change significantly from 1987 to 1996 among the uninsured.

The percent of ambulatory care visits that were for preventive reasons increased from 1987 to 1996.

The final aspect of health care use that we examine in this report is the reason for visits to health care providers. Table 3 displays the distribution of ambulatory care visits across four broad categories: visits for a general checkups or other preventive services, visits for the diagnosis or treatment of specific ailments, emergencies, and a residual category. One general trend is evident from Table 3; the percentage of ambulatory care visits that were for preventive reasons increased from 1987 to 1996 while the percentages for all other types of visits decreased. In 1987, 17 percent of all ambulatory care visits were for preventive purposes; but by 1996, 23 percent of all visits were preventive in nature.

Although preventive visits as a proportion of all ambulatory care visits have increased across most sociodemographic groups examined, the trend is particularly pronounced among individuals in higher income groups. In 1987, only 16 percent of ambulatory care visits among individuals in the wealthiest income category were for preventive purposes, but by 1996, this figure had jumped to 22 percent. For individuals in the poorest income groups, the change was not significant.

The trend toward more preventive service use is also more pronounced for children ages 6-17 than for people in other age groups. In 1987, only 10.5 percent of ambulatory care visits by children ages 6-17 were for preventive reasons, but by 1996, this figure had doubled to 21 percent.

Adults age 65 and over who were insured exclusively by Medicare had a dramatic increase in the proportion of ambulatory care visits that were for preventive reasons. In 1987, 20 percent of ambulatory care visits for people age 65 and over who had Medicare and no supplemental insurance were for preventive reasons; by 1996, 31 percent of their visits were for preventive reasons.

^top

Summary and Conclusions

This report explored changes in ambulatory care use from 1987 to 1996 in the civilian noninstitutionalized population. Three aspects of health care use were examined: the frequency with which individuals have ambulatory care visits, the settings in which visits take place, and the reasons for visits. We found that about three-quarters of the population had at least one ambulatory care visit during the year in both 1987 and 1996. However, other aspects of use changed. Among the most notable changes are the following:

• Among people age 65 and over who were covered exclusively by Medicare, the proportion with at least one ambulatory care visit increased substantially from 1987 to 1996.
• During this time period, the proportion of ambulatory care visits taking place in office-based settings increased while the proportion of visits taking place in hospital outpatient departments or emergency rooms decreased. This trend was most evident for blacks, people in lower income categories, and people with public health insurance.
• The proportion of ambulatory care visits that were for preventive reasons increased, especially among the higher income categories, children ages 6-17, and elderly people insured exclusively by Medicare.

The findings discussed in this report suggest that efforts on the part of health care organizations and insurance companies during the late 1980s and 1990s to discourage the use of hospital-based care and to encourage the use of preventive care may have had some effect. It should be noted, however, that these findings do not reflect changes in the pattern of health care utilization that occurred after 1996.

^top

References

Edwards WS, Berlin M. Questionnaires and data collection methods for the Household Survey and the Survey of American Indians and Alaskan Natives. Rockville (MD): National Center for Health Services Research and Health Care Technology Assessment; 1989. National Medical Expenditure Survey Methods 2. DHHS Pub. No. (PHS) 89-3450. Schappert SM. Ambulatory care visits to physician offices, hospital outpatient departments, and emergency departments: United States, 1996. National Center for Health Statistics; 1998. Vital Health Stat 13(134).

^top

Tables

Table 1. Ambulatory services^a- Total population, percent with any visit, and average number of visits per person with visit: United States, 1987 and 1996
 

Table 2. Ambulatory services a- Total number of visits and percent distribution by setting: United States, 1987 and 1996
 

Table 3. Ambulatory services ^a- Total number of visits and percent distribution by reason for visit: United States, 1987 and 1996
 

^top

Appendix

The data in this report were obtained in the first three rounds of interviews for the Household Component (HC) of the 1996 Medical Expenditure Panel Survey (MEPS) and the Household Survey of the 1987 National Medical Expenditure Survey (NMES).

MEPS is cosponsored by the Agency for Healthcare Research and Quality (AHRQ) and the National Center for Health Statistics (NCHS). NMES was sponsored by AHRQ’s predecessor, the National Center for Health Services Research. Both are nationally representative surveys of the U.S. civilian noninstitutionalized population that collect medical expenditure data at both the person and household levels. The focus of the MEPS HC and the NMES Household Survey is to collect detailed data on demographic characteristics, health conditions, health status, use of medical care services, charges and payments, access to care, satisfaction with care, health insurance coverage, income, and employment.

The data in this report were obtained in the first three rounds of interviews for the Household Component (HC) of the 1996 Medical Expenditure Panel Survey (MEPS) and the Household Survey of the 1987 National Medical Expenditure Survey (NMES).

MEPS is cosponsored by the Agency for Healthcare Research and Quality (AHRQ) and the National Center for Health Statistics (NCHS). NMES was sponsored by AHRQ’s predecessor, the National Center for Health Services Research. Both are nationally representative surveys of the U.S. civilian noninstitutionalized population that collect medical expenditure data at both the person and household levels. The focus of the MEPS HC and the NMES Household Survey is to collect detailed data on demographic characteristics, health conditions, health status, use of medical care services, charges and payments, access to care, satisfaction with care, health insurance coverage, income, and employment.

Survey Design

1996 MEPS

The sample for the 1996 MEPS HC was selected from respondents to the 1995 National Health Interview Survey (NHIS), which was conducted by NCHS. NHIS provides a nationally representative sample of the U.S. civilian noninstitutionalizied population and reflects an oversampling of Hispanics and blacks.

The MEPS HC collects data through an overlapping panel design. In this design, data are collected through a precontact interview that is followed by a series of five rounds of interviews over 2 1 /2 years. Interviews are conducted with one member of each family, who reports on the health care experiences of the entire family. Two calendar years of medical expenditure and utilization data are collected from each household and captured using computer-assisted personal interviewing (CAPI).

This series of data collection rounds is launched again each subsequent year on a new sample of households to provide overlapping panels of survey data that will produce continuous and current estimates of health care expenditures. This report uses Rounds 1-3 of the first MEPS panel to create utilization estimates for calendar year 1996.

1987 NMES

The 1987 NMES was designed to provide estimates of insurance coverage, use of services, expenditures, and sources of payment for the period from January 1, 1987, through December 31, 1987. The entire Household Survey was conducted in four interview rounds at approximately 4-month intervals, with a fifth short telephone interview at the end. Items related to health status, access to health care, and income were collected in special supplements that were administered over the course of the calendar year. For more information on the survey instruments and data collection methods for NMES, see Edwards and Berlin (1989).

Utilization Variables

The utilization variables used to derive estimates for this report are based on the number of ambulatory visits for health care that were reported as occurring in calendar years 1987 (from NMES) and 1996 (from MEPS).

Visit Setting

For both 1987 and 1996 estimates, ambulatory care events include visits to physician and nonphysician providers. Dental visits, home health visits, and telephone contact with office-based providers, regardless of provider type, are excluded from our estimates.

Examples of nonphysician providers include chiropractors, physical and occupational therapists, nurses and nurse practitioners, podiatrists, technicians, and receptionists, clerks, or secretaries. All events are classified by the setting in which they took place as follows: office visits, outpatient hospital visits, and emergency room visits. Same-day hospital discharges (hospital stays classified as inpatient that did not result in an overnight stay) are treated as outpatient hospital visits.

It should be noted that estimates of the number and proportion of visits taking place in emergency rooms based on MEPS are significantly lower than those based on the National Ambulatory Medical Care Survey (NAMCS) and the National Hospital Ambulatory Medical Care Survey (NHAMCS). MEPS is a household survey of the civilian noninstitutionalized population, while NAMCS and NHAMCS are provider-based surveys of doctors’offices and hospitals, respectively. These surveys use different methodologies in counting and classifying ambulatory visits. For estimates based on NAMCS and NHAMCS, see Schappert (1998).

Reason for Visit

Both the NMES and MEPS questionnaires asked respondents to report the main reason for visiting their health care provider. Based on the responses, visits were classified as follows:

• Preventive visits—For both 1987 and 1996, office visits and outpatient hospital visits were categorized as being for preventive purposes if respondents said the visits were for a general checkup, maternity care, well-child exam, or immunizations.
• Diagnosis or treatment—Because questions were not identical in 1987 and 1996, edits were made to ensure the greatest possible comparability. For 1987, office visits and outpatient hospital visits were categorized as being for diagnosis or treatment if respondents reported that the main reason for the visit was diagnosis or treatment, psychotherapy, reproductive services, foot care, physical or speech therapy, or any diagnostic test (e.g., diagnostic imaging or lab tests). For 1996, office visits and outpatient hospital visits were categorized as being for diagnosis or treatment of a specific ailment if respondents reported going to their provider for diagnosis or treatment, psychotherapy, or postoperative services. In addition, office visits and outpatient hospital visits were categorized as being for diagnostic or treatment purposes if a respondent indicated that one or more of the following services were received: physical therapy, speech therapy, chemotherapy, radiation therapy, kidney dialysis, intravenous therapy, drug treatment, psychotherapy, or diagnostic imaging
• Emergency—Only emergency room visits were categorized as being in the emergency category. Although MEPS respondents could identify a visit as being for emergency purposes regardless of the setting, NMES did not allow this. To make the data from the two surveys comparable, we considered all 1996 ambulatory care visits that did not take place in an emergency room as non-emergencies and assigned them to one of the other categories, as described above.
• Other—This residual category is made up of visits for which no reason was ascertained, including responses of "don’t know" or "other" and refusals.

Population Characteristics

Race/Ethnicity

Classification by race and ethnicity is based on information reported for each household member. In both MEPS and NMES, respondents were asked if their race was best described as American Indian, Alaska Native, Asian or Pacific Islander, black, white, or other.

In this report, American Indians, Alaska Natives, Asians, and Pacific Islanders are included in the "other" category. Respondents in both surveys also were asked if each family member’s main national origin or ancestry was Puerto Rican; Cuban, Mexican, Mexicano, Mexican American, or Chicano; other Latin American; or other Spanish. All persons whose main national origin or ancestry was reported in one of these Hispanic groups, regardless of racial background, were classified as Hispanic. Since the Hispanic grouping can include black Hispanic, white Hispanic, and other Hispanic, the race categories of white, black, and other do not include Hispanic persons.

Income

Each sample person was classified according to the total 1987 or 1996 income of his or her family. Within a household, all individuals related by blood, marriage, or adoption were considered to be a family. Personal income from all family members was summed to create family income. Possible sources of income included annual earnings from wages, salaries, bonuses, tips, and commissions; business and farm gains and losses; unemployment and Worker’s Compensation; interest and dividends; alimony, child support, and other private cash transfers; private pensions, individual retirement account (IRA) withdrawals, Social Security, and Department of Veterans Affairs payments; Supplemental Security Income and cash welfare payments from public assistance, Aid to Families with Dependent Children, and Aid to Dependent Children; gains or losses from estates, trusts, partnerships, corporations, rent, and royalties; and a small amount of "other" income.

Poverty status is the ratio of family income to the 1987 or 1996 Federal poverty thresholds, which control for family size and age of the head of family.

Categories are defined as follows:

• Poor—This refers to persons in families with income less than or equal to the poverty line and includes those who reported negative income.
• Near-poor—This group includes persons in families with income over the poverty line through 125 percent of the poverty line.
• Low income—This category includes persons in families with income over 125 percent through 200 percent of the poverty line.
• Middle income—This category includes persons in families with income over 200 percent through 400 percent of the poverty line.
• High income—This category includes persons in families with income over 400 percent of the poverty line.

Health Insurance Status

Individuals under age 65 were classified into the following three insurance categories:

• Any private health insurance—Individuals who, at any time during the year (1987 or 1996), had insurance that provides coverage for hospital and physician care (other than Medicare, Medicaid, or other public hospital/physician coverage) are classified as having private insurance. Coverage by CHAMPUS/CHAMPVA (Armed-Forces-related coverage) is also included as private health insurance. Insurance that provides coverage for a single service only, such as dental or vision coverage, is not included.
• Public coverage only—Individuals are considered to have public coverage only if they met both of the following criteria:  - They were not covered by private insurance at any time during the year. - They were covered by one of the following public programs at any point during the year: Medicare, Medicaid, or other public hospital/physician coverage.
• Uninsured—The uninsured are defined as people not covered by Medicare, CHAMPUS/CHAMPVA, Medicaid, other public hospital/physician programs, or private hospital/physician insurance at any time during the entire year or period of eligibility for the survey. Individuals covered only by noncomprehensive State-specific programs (e.g., Maryland Kidney Disease Program, Colorado Child Health Plan) or private single-service plans (e.g., coverage for dental or vision care only, coverage for accidents or specific diseases) are not considered to be insured.

Individuals age 65 and over were classified into the following three insurance categories:

• Medicare only.
• Medicare and private.
• Medicare and other public.

Perceived Health Status

The NMES questionnaire asked respondents to rate the health of each person in the family according to the following four categories: excellent, good, fair, and poor. The MEPS questionnaire asked respondents to rate the health of each person in the family according to the following five categories: excellent, very good, good, fair, and poor. For the tables in this report, these categories were collapsed into the following two broad categories: (1) excellent, very good, or good health and (2) fair or poor health.

Place of Residence

Individuals are identified as residing either inside or outside a metropolitan statistical area (MSA) as designated by the U.S. Office of Management and Budget, which applied 1990 standards using population counts from the 1990 U.S. census. An MSA is a large population nucleus combined with adjacent communities that have a high degree of economic and social integration with the nucleus. Each MSA has one or more central counties containing the area’s main population concentration. In New England, metropolitan areas consist of cities and towns rather than whole counties. MSA data are based on MSA status as of December 31, 1996. If MSA status as of December 31 was not known, then MSA status at the time of the Round 3 interview was used.

Region

Each MEPS sample person was classified as living in one of the following four regions as defined by the Bureau of the Census:

• Northeast - Maine, New Hampshire, Vermont, Massachusetts, Rhode Island, Connecticut, New York, New Jersey, and Pennsylvania.
• Midwest - Ohio, Indiana, Illinois, Michigan, Wisconsin, Minnesota, Iowa, Missouri, North Dakota, South Dakota, Nebraska, and Kansas.
• South - Delaware, Maryland, District of Columbia, Virginia, West Virginia, North Carolina, South Carolina, Georgia, Florida, Kentucky, Tennessee, Alabama, Mississippi, Arkansas, Louisiana, Oklahoma, and Texas.
• West - Montana, Idaho, Wyoming, Colorado, New Mexico, Arizona, Utah, Nevada, Washington, Oregon, California, Alaska, and Hawaii.

Rounding

Estimates presented in the tables were rounded to the nearest 0.1 percent. Standard errors, presented in tables A-C, were rounded to the nearest 0.01. Therefore, some of the estimates for population totals of subgroups presented in the tables will not add exactly to the overall estimated population total.