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

James B. Kirby, Ph.D., Steven R. Machlin, M.S., and Joshua M. Thorpe, M.P.H., Agency for Healthcare Research and Quality



Abstract

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.

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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.

Overall ambulatory care use changed little from 1987 to 1996. However, there were some noteworthy changes for people age 65 and over who were covered by Medicare only: 77 percent of them had at least one ambulatory care visit in 1987, but by 1996, this figure had risen to 86 percent. In 1987, elderly people covered exclusively by Medicare were substantially less likely to have a visit than the elderly who had Medicare plus some other health insurance, public or private. In contrast, by 1996, those covered exclusively by Medicare were nearly as likely as others to have an ambulatory visit.

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Visit Setting

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

Another important component of health care service use is the setting in which care is provided. Table 2 displays national estimates of the proportion of ambulatory care visits that take place in three settings: a health care provider’s office, a hospital outpatient department,  and a hospital emergency department. 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.

This change is apparent within all sociodemographic groups examined in this report. The most pronounced changes, however, are for blacks, the poor, and the publicly insured.

In 1987, nearly 20 percent of all visits among blacks took place in outpatient hospital settings; in 1996, the corresponding figure was only 11 percent.

Blacks also showed a more marked decline than whites and Hispanics in the percentage of visits that took place in emergency rooms. As a portion of all ambulatory care visits by blacks, emergency rooms visits fell from 8 percent in 1987 to 5 percent in 1996.

The percentage of ambulatory care visits occurring in hospital outpatient departments and emergency rooms decreased more from 1987 to 1996 for people with lower incomes than for those with higher incomes.

In 1987, over 15 percent of all ambulatory care visits by people in the poorest income category were in outpatient hospital settings, but by 1996 this figure declined to 10 percent. In comparison, among those in the wealthiest income group, the percentage of ambulatory care visits that took place in outpatient hospital settings did not change significantly from 1987 to 1996. The percentage of ambulatory care visits that took place in emergency rooms also declined more for poor people from 1987 to 1996 than for wealthier people. In 1987, 7 percent of all ambulatory care visits by people in the lowest income category were to emergency rooms; in 1996, only 5 percent of ambulatory care visits among the poor were in emergency rooms. Although the proportion of ambulatory care visits that took place in emergency rooms declined for other income groups as well, the declines were smaller and some groups showed no change across the period.

With respect to insurance status, the increase in the proportion of ambulatory care visits in office-based settings and decrease in the proportion of visits in hospital outpatient and emergency departments are most pronounced for those with public insurance. In 1987, 18 percent of ambulatory care visits for people under age 65 who were insured exclusively by a public plan (mostly Medicaid) were in hospital outpatient settings.

By 1996, however, this percentage had declined by nearly half, to 9 percent. Similarly, there was a very large decrease from 1987 to 1996 in the proportion of ambulatory care visits that took place in outpatient hospital settings among people age 65 and over who were insured exclusively by Medicare or had Medicare plus supplemental public insurance. This decline was particularly pronounced for the group with Medicare only, which experienced a 50-percent reduction in the proportion of ambulatory care visits that took place in outpatient hospital settings. In contrast, the proportion of ambulatory visits to outpatient departments remained fairly constant for both the non-elderly and elderly with private health insurance.

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.

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Reason for Visit

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.

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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.

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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).

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Tables

Tables showing information on ambulatory services:
1. Percent of population with a visit and average number of visits per person with visit 
2. Setting of visit
3. Reason for visit

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

  1987 1996
Population characteristic Total population (in thousands) Percent of U.S. population Percent with any visit Average number of visits for those with any Total population (in thousands Percent of U.S. population Percent with any visit Average number for those with any
  Percent distribution Percent distribution
Total

239,393

100 75.6 6.9 268,905 100.0 74.9 7.1
Total age in years                
Under 6

22,133

9.3 85.8 5.3 23,861 8.9 85.0 4.5
6-17

41,616

17.4 70.0 4.8 47,634 17.7 68.6 4.0
18-44 102,117 42.7 70.7 6.6 109,149 40.6 68.6 6.7
45-64 45,232 18.9 78.9 8.1 54,212 20.2 79.1 8.9
65 and over 28,295 11.8 88.3 9.7 34,050 12.7 89.5 10.5
Race/ethnicity
White 183,396 76.6 78.7 7.2 193,708 72.0 78.8 7.5
Black 28,567 11.9 66.6 5.9 33,668 12.5 65.3 5.7
Hispanic 19,186 8.0 64.6 5.2 29,979 11.2 63.3 6.0
Other 8,244 3.4 63.0 5.5 11,550 4.3 66.3 5.2
Sex
Male 115,861 48.4 70.1 6.3 131,527 48.9 69.2 6.4
Female 123,532 51.6 80.7 7.4 137,379 51.1 80.3 7.6
Metropolitan statistical area (MSA)b
MSA 181,264 75.7 75.8 7.1 213,820 80.3 75.1 7.1
Non-MSA 58,129 24.3 75.0 6.4 52,443 19.7 74.1 7.0
Census Region
Northeast 47,539 19.9 77.4 7.4 51,965 19.3 77.4 7.7
Midwest 60,498 25.3 77.6 7.1 62,673 23.3 77.8 6.9
South 83,958 35.1 72.4 6.2 93,901 34.9 73.5 6.7
West 47,398 33.3 76.9 7.4 60,366 22.5 71.7 7.3
Income
Poor 31,187 13.1 70.6 6.6 38,298 14.2 70.8 7.6
Near-poor 10,882 4.6 72.8 6.8 12,946 4.8 71.4 7.1
Low income 33,290 14.0 72.7 7.0 40,460 15.1 70.2 6.7
Middle income 83,518 35.1 76.5 6.8 88,262 32.8 74.8 6.7
High Income 79,267 33.3 78.4 7.1 88,939 33.1 79.2 7.3
Health insurance statusb,d
Under 65 years                  
Any private 164,232 68.8 76.7 6.5 174,231 64.8 76.3 6.4
Public only 22,738 9.5 75.7 7.7 27,845 10.4 76.1 8.0
Uninsured 24,128 10.1 53.1 4.8 32,780 12.2 51.1 4.9
65 years and over                
Medicare only 3,137 1.3 76.7 7.5 7,535 2.8 86.3 8.8
Medicare and private 21,379 9.0 90.4 9.9 22,811 8.5 91.3 11.2
Medicare and other public 2,946 1.2 91.6 10.8 3,555 1.3 88.2 10.2
Perceived health statusb
Excellent, very good, or good 174,918 82.9 74.0 6.1 239,088 89.5 73.3 6.2
Fair or poor 36,043 17.1 85.8 10.9 28,125 10.5 89.8 13.6

a Ambulatory services are visits to medical providers seen in office-based settings or clinics, hospital outpatient departments, emergency rooms (except visits resulting in an overnight hospital stay), and clinics owned and operated by hospitals.  Events reported as hospital admissions without an overnight stay are included.

b Numbers of persons do not add to overall total because data on this variable were not available for some sample persons.

c Poor refers to incomes below the Federal poverty line; near-poor, over the poverty line through 125 percent of the poverty line; low income, over 125 percent through 2000 percent of the poverty line; middle income, over 200 percent to 400 percent of the poverty line; and high income, over 400 percent of the poverty line.

d Uninsured refers to persons uninsured during the entire year.  Public and private health insurance categories refer to individuals with public or private insurance at any time during the period; individuals with both public and private insurance and those with CHAMPUS or CHAMPVA (Armed-Forces-related coverage) are classified as having private insurance.

Note: Restricted to civilian noninstitutionalized population.  Percents may not add to 100 because of rounding.

Source: Center for Financing, Access, and Cost Trends, Agency for Healthcare Research and Quality: National Medical Expenditure Survey, 1987, and Medical Expenditure Panel Survey, 1996.

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

  1987 1996
Population characteristic Total visits
(in millions)
Office-
based
Outpatient
department
Emergency Room Total visits
(in millions)
Office-
based
Outpatient
department
Emergency Room
  Percent distribution Percent distribution
Total 1,250.7 84.9 10.8 4.3 1,423.6 87.8 8.9 3.3
Total age in years                
Under 6 101.0 85.4 7.7 6.8 91.1 90.2 4.5 5.3
6-17 140.7 87.0 7.0 5.9 131.2 90.0 4.6 5.4
18-44 475.9 86.0 9.4 4.6 498.4 89.1 7.0 3.9
45-64 290.0 84.1 12.9 3.0 381.5 86.7 11.1 2.1
65 and over 243.1 82.4 14.5 3.1 321.4 85.6 12.4 2.1
Race/ethnicity
White 1,046.4 86.3 9.9 3.8 1,146.4 88.0 9.1 3.0
Black 111.7 72.4 19.6 8.0 124.7 84.4 11.1 4.5
Hispanic 64.0 85.2 9.3 5.5 113.0 88.7 6.7 4.6
Other 28.7 82.4 12.4 5.2 39.6 91.6 5.0 3.5
Sex
Male 512.6 83.6 11.4 5.0 580.7 86.8 9.4 3.8
Female 738.1 85.8 10.4 3.8 842.9 88.5 8.6 2.9
Metropolitan statistical area (MSA)b
MSA 973.6 84.9 11.1 4.0 1,139.9 88.6 9.4 3.8
Non-MSA 277.1 85.0 9.9 5.2 272.3 88.5 8.6 2.9
Census Region
Northeast 272.7 84.6 11.0 4.4 311.0 87.3 9.8 2.9
Midwest 333.1 84.9 11.3 3.9 334.6 84.7 11.3 4.0
South 376.2 84.0 10.9 5.1 462.3 88.8 7.8 3.4
West 268.8 86.6 9.9 3.5 315.7 90.1 7.3 2.6
Income
Poor 149.8 78.4 14.5 7.1 206.5 85.2 10.1 4.7
Near-poor 54.1 79.2 14.0 6.8 66.0 83.2 12.2 4.7
Low income 169.1 83.1 11.6 5.3 191.5 86.3 9.4 4.3
Middle income 434.7 85.5 10.7 3.8 441.9 88.2 8.5 3.2
High Income 443.1 88.0 9.0 3.0 517.7 89.6 8.3 2.1
Health insurance statusb,d
Under 65 years                
Any private 814.2 87.6 8.5 3.9 849.8 89.2 7.8 3.0
Public only 131.9 74.5 17.8 7.7 169.8 85.8 8.8 5.3
Uninsured 61.6 81.0 12.3 6.7 82.7 86.4 7.6 6.0
65 years and over                 
Medicare only 18.1 71.0 25.2 3.8 57.2 85.1 12.6 2.3
Medicare and private 191.6 84.1 13.1 2.8 232.3 85.4 12.6 1.9
Medicare and other public 29.2 79.3 15.6 5.1 31.8 87.4 9.8 2.8
Perceived health statusb
Excellent, very good, or good 788.6 87.0 9.0 4.0 1,077.8 88.8 8.0 3.2
Fair or poor 338.0 80.7 14.9 4.4 343.3 84.9 11.8 3.3

a Frequencies and percentages regarding visits to medical providers seen in office-based settings or clinics, hospital outpatient departments, emergency rooms (except visits resulting in an overnight hospital stay), and clinics owned and operated by hospitals, as well as expenses for events reported as hospital admissions without an overnight stay, are included.

b Numbers of visits do not add to overall total because data on this variable were not available for some sample persons.

c Poor refers to incomes below the Federal poverty line; near-poor, over the poverty line through 125 percent of the poverty line; low income, over 125 percent through 200 percent of the poverty line; middle income, over 200 percent to 400 percent of the poverty line; and high income, over 400 percent of the poverty line.

d Uninsured refers to persons uninsured during the entire year.  Public and private health insurance categories refer to individuals with public or private insurance at any time during the period; individuals with both public and private insurance and those with CHAMPUS or CHAMPVA (Armed-Forces-related coverage) are classified as having private insurance.

Note: Restricted to civilian noninstitutionalized population.  Percents may not add to 100 because of rounding.

Source: Center for Financing, Access, and Cost Trends, Agency for Healthcare Research and Quality: National Medical Expenditure Survey, 1996.

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

  1987 1996
Population characteristic Total visits
(in millions)
Office-
based
Outpatient
department
Emergency Room Total visits
(in millions)
Office-
based
Outpatient
department
Emergency Room
  Percent distribution Percent distribution
Total 1,250.7 84.9 10.8 4.3 1,423.6 87.8 8.9 3.3
Total age in years                
Under 6 101.0 85.4 7.7 6.8 91.1 90.2 4.5 5.3
6-17 140.7 87.0 7.0 5.9 131.2 90.0 4.6 5.4
18-44 475.9 86.0 9.4 4.6 498.4 89.1 7.0 3.9
45-64 290.0 84.1 12.9 3.0 381.5 86.7 11.1 2.1
65 and over 243.1 82.4 14.5 3.1 321.4 85.6 12.4 2.1
Race/ethnicity
White 1,046.4 86.3 9.9 3.8 1,146.4 88.0 9.1 3.0
Black 111.7 72.4 19.6 8.0 124.7 84.4 11.1 4.5
Hispanic 64.0 85.2 9.3 5.5 113.0 88.7 6.7 4.6
Other 28.7 82.4 12.4 5.2 39.6 91.6 5.0 3.5
Sex
Male 512.6 83.6 11.4 5.0 580.7 86.8 9.4 3.8
Female 738.1 85.8 10.4 3.8 842.9 88.5 8.6 2.9
Metropolitan statistical area (MSA)b
MSA 973.6 84.9 11.1 4.0 1,139.9 88.6 9.4 3.8
Non-MSA 277.1 85.0 9.9 5.2 272.3 88.5 8.6 2.9
Census Region
Northeast 272.7 84.6 11.0 4.4 311.0 87.3 9.8 2.9
Midwest 333.1 84.9 11.3 3.9 334.6 84.7 11.3 4.0
South 376.2 84.0 10.9 5.1 462.3 88.8 7.8 3.4
West 268.8 86.6 9.9 3.5 315.7 90.1 7.3 2.6
Income
Poor 149.8 78.4 14.5 7.1 206.5 85.2 10.1 4.7
Near-poor 54.1 79.2 14.0 6.8 66.0 83.2 12.2 4.7
Low income 169.1 83.1 11.6 5.3 191.5 86.3 9.4 4.3
Middle income 434.7 85.5 10.7 3.8 441.9 88.2 8.5 3.2
High Income 443.1 88.0 9.0 3.0 517.7 89.6 8.3 2.1
Health insurance statusb,d
Under 65 years                
Any private 814.2 87.6 8.5 3.9 849.8 89.2 7.8 3.0
Public only 131.9 74.5 17.8 7.7 169.8 85.8 8.8 5.3
Uninsured 61.6 81.0 12.3 6.7 82.7 86.4 7.6 6.0
65 years and over                 
Medicare only 18.1 71.0 25.2 3.8 57.2 85.1 12.6 2.3
Medicare and private 191.6 84.1 13.1 2.8 232.3 85.4 12.6 1.9
Medicare and other public 29.2 79.3 15.6 5.1 31.8 87.4 9.8 2.8
Perceived health statusb
Excellent, very good, or good 788.6 87.0 9.0 4.0 1,077.8 88.8 8.0 3.2
Fair or poor 338.0 80.7 14.9 4.4 343.3 84.9 11.8 3.3

a Frequencies and percentages regarding visits to medical providers seen in office-based settings or clinics, hospital outpatient departments, emergency rooms (except visits resulting in an overnight hospital stay), and clinics owned and operated by hospitals, as well as expenses for events reported as hospital admissions without an overnight stay, are included.

b Numbers of visits do not add to overall total because data on this variable were not available for some sample persons.

c Poor refers to incomes below the Federal poverty line; near-poor, over the poverty line through 125 percent of the poverty line; low income, over 125 percent through 200 percent of the poverty line; middle income, over 200 percent to 400 percent of the poverty line; and high income, over 400 percent of the poverty line.

d Uninsured refers to persons uninsured during the entire year.  Public and private health insurance categories refer to individuals with public or private insurance at any time during the period; individuals with both public and private insurance and those with CHAMPUS or CHAMPVA (Armed-Forces-related coverage) are classified as having private insurance.

Note: Restricted to civilian noninstitutionalized population.  Percents may not add to 100 because of rounding.

Source: Center for Financing, Access, and Cost Trends, Agency for Healthcare Research and Quality: National Medical Expenditure Survey, 1996.

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Appendix

Survey Design Standard Errror Table A
Utilization Variable Standard Errror Table B
Population Characteristics Standard Errror Table C
Rounding

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.

Table A. Standard errors for ambulatory servicesa - Total population, percent with any visit, and average number of visits per person with visit: United States, 1987 and 1996

Population characteristic

1987

1996

Total population (in thousands)
Percent of U.S. population
Percent with any visit
Average number of visits for those with any
Total population (in thousands)
Percent of U.S. population
Percent with any visit
Average number of visits for those with any
Total
--
0.4
0.1
--
0.4
0.1
Age in years
Under 6
0.2
0.8
0.2
0.3
1.1
0.1
6-17
0.3
0.9
0.2
0.4
1.0
0.1
18-44
0.4
0.4
0.1
0.5
0.6
0.2
45-64
0.3
0.6
0.2
0.4
0.7
0.3
65 and over
0.3
0.5
0.2
0.4
0.7
0.3
Race/ethnicity
White
1.1
0.4
0.1
0.8
0.4
0.1
Black
0.7
1.0
0.2
0.7
1.2
0.3
Hispanic
0.8
1.1
0.2
0.6
1.1
0.6
Other
0.5
2.0
0.4
0.4
2.4
0.5
Sex
Male
0.3
0.5
0.1
0.3
0.6
0.2
Female
0.3
0.4
0.1
0.3
0.5
0.2
Metropolitan statistical area (MSA)b
MSA
1.5
0.4
0.1
1.0
0.5
0.1
Non-MSA
1.5
0.9
0.1
1.0
1.0
0.3
Census Region
Northeast
0.8
0.7
0.2
0.8
1.0
0.3
Midwest
0.8
0.7
0.2
1.0
0.7
0.2
South
0.8
0.6
0.1
1.2
0.7
0.2
West
0.9
0.7
0.3
0.8
1.0
0.4
Incomec
Poor
0.6
1.1
0.2
0.5
1.0
0.5
Near-poor
0.3
1.4
0.3
0.3
1.8
0.7
Low income
0.4
0.9
0.2
0.5
1.1
0.2
Middle income
0.6
0.6
0.2
0.7
0.7
0.2
High income
0.7
0.5
0.2
0.9
0.7
0.2
Health insurance statusb,d
Under 65 years
 
 
 
 
 
 
 
 
Any private
2,760
0.8
0.4
0.1
4,618
0.8
0.5
0.1
Public only
1,286
0.5
1.0
0.1
1,401
0.5
1.1
0.7
Uninsured
1,045
0.4
1.1
0.4
1,394
0.4
1.3
0.3
65 years and over
 
 
 
 
 
 
 
 
Medicare only
165
0.1
1.7
0.7
480
0.2
1.7
0.6
Medicare and private
748
0.3
0.5
0.3
906
0.3
0.8
0.4
Medicare and other public
244
0.1
1.3
0.6
271
0.1
2.0
1.0
Perceived health statusb
Excellent, very good, or good
2,428
0.4
0.4
0.1
5,371
0.3
0.4
0.1
Fair or poor
970
0.4
0.7
0.3
978
0.3
0.8
0.6
a Ambulatory services are visits to medical providers seen in office- based settings or clinics, hospital outpatient departments, emergency rooms (except visits resulting in an overnight hospital stay), and clinics owned and operated by hospitals, as well as expenses for events reported as hospital admissions without an overnight stay, are included.

b Data on this variable were not available for some sample persons.

c Poor refers to incomes below the Federal poverty line; near- poor, over the poverty line through 125 percent of the poverty line; low income, over 125 percent through 200 percent of the poverty line; middle income, over 200 percent to 400 percent of the poverty line; and high income, over 400 percent of the poverty line.

d Uninsured refers to persons uninsured during the entire year. Public and private health insurance categories refer to individuals with public or private insurance at any time during the period; individuals with both public and private insurance and those with CHAMPUS or CHAMPVA (Armed- Forces- related coverage) are classified as having private insurance.

Standard error approximately zero because of poststratification to Census Bureau population control tables.

Note: Restricted to civilian noninstitutionalized population.

Source: Center for Financing, Access, and Cost Trends, Agency for Healthcare Research and Quality: National Medical Expenditure Survey, 1987, and Medical Expenditure Panel Survey, 1996.

Table B. Standard errors for ambulatory servicesa - Total number  of visits  and percent distribution by setting: United States, 1987 and 1996

Population characteristic

1987

1996

Total visits (in millions)
Office-based
Outpatient department
Emergency room
Total visits (in millions)
Office-based
Outpatient department
Emergency room
Total 23.4 0.5 0.4 0.1 39.7 0.4 0.4 0.1
Age in years
Under 6 5.0 1.2 0.9 0.4 4.6 0.6 0.5 0.3
6-17 6.7 0.8 0.7 0.3 6.3 0.7 0.6 0.3
18-44 13.1 0.6 0.5 0.2 23.2 0.6 0.5 0.2
45-64 9.7 0.9 0.9 0.1 16.1 0.8 0.8 0.1
65 and over 9.0 1.0 0.9 0.1 15.1 1.0 1.0 0.1
Race/ethnicity
White 23.6 0.5 0.4 0.1 34.1 0.4 0.4 0.1
Black 7.5 1.8 1.8 0.5 10.2 1.7 1.8 0.4
Hispanic 6.0 1.2 1.0 0.4 11.9 1.3 1.0 0.5
Other 4.7 2.4 2.4 0.7 5.6 1.5 1.0 0.7
Sex
Male 13.3 0.6 0.6 0.2 21.2 0.6 0.6 0.2
Female 15.3 0.6 0.5 0.1 24.5 0.5 0.5 0.1
Metropolitan statistical area (MSA)b
MSA 30.2 0.6 0.5 0.1 33.8 0.4 0.4 0.1
Non-MSA 15.8 0.9 0.8 0.3 21.6 1.4 1.3 0.3
Census Region
Northeast 16.1 0.8 0.7 0.2 15.7 0.7 0.6 0.2
Midwest 11.6 0.8 0.7 0.2 18.1 0.9 0.9 0.2
South 11.7 1.0 1.0 0.2 24.0 0.7 0.7 0.2
West 15.7 1.0 1.0 0.2 21.2 0.9 0.8 0.2
Incomec
Poor 8.3 1.4 1.2 0.5 16.3 1.4 1.3 0.4
Near-poor 3.8 1.7 1.5 0.6 6.9 3.1 3.2 0.7
Low income 8.2 0.9 0.9 0.3 10.1 1.0 1.0 0.3
Middle income 13.9 0.6 0.6 0.1 17.2 0.5 0.5 0.2
High income 13.9 0.5 0.5 0.1 21.8 0.6 0.5 0.1
Health insurance statusb,d
Under 65 years                
Any private 21.5 0.4 0.4 0.1 28.2 0.4 0.4 0.1
Public only 8.8 1.9 1.7 0.5 16.9 1.4 1.1 0.6
Uninsured 4.0 1.6 1.5 0.5 6.4 1.4 1.2 0.6
65 years and over                
Medicare only 2.0 5.8 6.1 0.5 5.3 3.4 3.5 0.3
Medicare and private 8.2 0.9 0.9 0.1 13.0 1.1 1.1 0.2
Medicare and other public 2.9 2.5 2.5 0.4 4.0 2.4 2.4 0.5
Perceived health statusb
Excellent, very good, or good 18.5 0.5 0.4 0.1 30.4 0.4 0.4 0.1
Fair or poor 11.5 0.9 0.9 0.2 18.9 1.0 1.0 0.2

a Frequencies and percentages regarding visits to medical providers seen in office- based settings or clinics, hospital outpatient departments, emergency rooms (except visits resulting in an overnight hospital stay), and clinics owned and operated by hospitals, as well as expenses for events reported as hospital admissions without an overnight stay, are included.

b Data on this variable were not available for some sample persons.

c Poor refers to incomes below the Federal poverty line; near- poor, over the poverty line through 125 percent of the poverty line; low income, over 125 percent through 200 percent of the poverty line; middle income, over 200 percent to 400 percent of the poverty line; and high income, over 400 percent of the poverty line.

d Uninsured refers to persons uninsured during the entire year. Public and private health insurance categories refer to individuals with public or private insurance at any time during the period; individuals with both public and private insurance and those with CHAMPUS or CHAMPVA (Armed- Forces- related coverage) are classified as having private insurance.

Standard error approximately zero because of poststratification to Census Bureau population control tables.

Note: Restricted to civilian noninstitutionalized population.

Source: Center for Financing, Access, and Cost Trends, Agency for Healthcare Research and Quality: National Medical Expenditure Survey, 1987, and Medical Expenditure Panel Survey, 1996.

Table C. Standard errors for ambulatory servicesa - Total number  of visits  and percent distribution by reason for visit: United States, 1987 and 1996
 

Population characteristic

1987

1996

Total visits (in millions)
Preventive services
Diagnosis and/or treatment
Emergency 
Other
Total visits (in millions)
Preventive services
Diagnosis and/or treatment
Emergency 
Other
Total
23.4
0.4
0.5
0.1
0.3
39.7
0.5
0.6
0.1
0.4
Age in years
Under 6
5.0
1.2
1.3
0.4
0.8
4.6
1.1
1.2
0.3
0.2
6-17
6.7
0.6
1.1
0.3
1.2
6.3
1.1
1.4
0.3
1.0
18-44
13.1
0.5
0.7
0.2
0.4
23.2
0.9
1.1
0.2
0.5
45-64
9.7
0.6
0.7
0.1
0.6
16.1
0.7
1.0
0.1
0.9
65 and over
9.0
0.7
0.8
0.1
0.5
15.1
0.8
1.0
0.1
0.5
Race/ethnicity
White
23.6
0.4
0.5
0.1
0.4
34.1
0.5
0.7
0.1
0.4
Black
7.5
1.0
1.4
0.5
0.6
10.2
1.4
1.8
0.4
1.5
Hispanic
6.0
1.3
1.5
0.4
0.9
11.9
2.4
3.2
0.5
0.6
Other
4.7
1.7
1.7
0.7
1.5
5.6
2.8
3.5
0.7
0.9
Sex
Male
13.3
0.4
0.7
0.2
0.6
21.2
0.7
0.9
0.2
0.4
Female
15.3
0.4
0.5
0.1
0.3
24.5
0.6
0.7
0.1
0.5
Metropolitan statistical area (MSA)b
MSA
30.2
0.4
0.6
0.1
0.4
33.8
0.5
0.7
0.1
0.4
Non-MSA
15.8
0.8
0.9
0.3
0.5
21.6
1.3
1.5
0.3
0.6
Census Region
Northeast
16.1
1.0
1.5
0.2
1.0
15.7
1.0
1.5
0.2
1.3
Midwest
11.6
0.7
0.7
0.2
0.4
18.1
0.9
1.0
0.2
0.4
South
11.7
0.6
0.8
0.2
0.6
24.0
0.7
0.9
0.2
0.4
West
15.7
0.6
0.5
0.2
0.5
21.2
1.2
1.5
0.2
0.8
Incomec
Poor
8.3
1.0
1.4
0.5
0.8
16.3
1.7
2.4
0.4
1.7
Near-poor
3.8
1.4
1.8
0.6
1.2
6.9
2.2
3.2
0.7
1.7
Low income
8.2
0.8
1.0
0.3
0.9
10.1
1.1
1.3
0.3
0.7
Middle income
13.9
0.5
0.6
0.1
0.4
17.2
0.7
0.9
0.2
0.5
High income
13.9
0.6
0.7
0.1
0.4
21.8
0.7
0.8
0.1
0.5
Health insurance statusb,d
Under 65 years
 
 
 
 
 
 
 
 
 
Any private
21.5
0.5
0.6
0.1
0.4
28.2
0.5
0.6
0.1
0.4
Public only
8.8
1.2
1.6
0.5
0.5
16.9
2.2
3.1
0.6
2.0
Uninsured
4.0
1.2
1.8
0.5
1.4
6.4
1.2
1.8
0.6
1.2
65 years and over
 
 
 
 
 
 
 
 
 
Medicare only
2.0
2.2
2.9
0.5
1.4
5.3
1.7
1.9
0.3
1.0
Medicare and private
8.2
0.7
0.8
0.1
0.4
13.0
0.9
1.2
0.2
0.7
Medicare and other public
2.9
1.8
2.6
0.5
2.3
4.0
3.4
4.0
0.5
0.7
Perceived health statusb
Excellent, very good, or good
18.5
0.4
0.6
0.1
0.4
30.4
0.5
0.6
0.1
0.3
Fair or poor
11.5
0.6
0.7
0.2
0.5
18.9
1.0
1.5
0.2
1.1

a Frequencies and percentages regarding visits to medical providers seen in office- based settings or clinics, hospital outpatient departments, emergency rooms (except visits resulting in an overnight hospital stay), and clinics owned and operated by hospitals, as well as expenses for events reported as hospital admissions without an overnight stay, are included.

b Data on this variable were not available for some sample persons.

c Poor refers to incomes below the Federal poverty line; near- poor, over the poverty line through 125 percent of the poverty line; low income, over 125 percent through 200 percent of the poverty line; middle income, over 200 percent to 400 percent of the poverty line; and high income, over 400 percent of the poverty line.

d Uninsured refers to persons uninsured during the entire year. Public and private health insurance categories refer to individuals with public or private insurance at any time during the period; individuals with both public and private insurance and those with CHAMPUS or CHAMPVA (Armed- Forces- related coverage) are classified as having private insurance. 

Note: Restricted to civilian noninstitutionalized population.

Source: Center for Financing, Access, and Cost Trends, Agency for Healthcare Research and Quality: National Medical Expenditure Survey, 1987, and Medical Expenditure Panel Survey, 1996.

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Suggested Citation:
Kirby, J. B., Machlin, S. R., and Thorpe, J. M. Research Findings #16: Patterns of Ambulatory Care Use: Changes from 1987 to 1996. July 2001. Agency for Healthcare Research and Quality, Rockville, MD. http://www.meps.ahrq.gov/data_files/publications/rf16/rf16.shtml