Series 13, Number 150 No

vember 2001

Revised

Trends in Hospital

Emergency Department

Utilization: United States,

1992–99
Copyright information

All material appearing in this report is in the public domain and may be

reproduced or copied without permission; citation as to source, however, is

appreciated.

Suggested Citation

Burt CW, McCaig LF. Trends in hospital emergency department utilization:

United States, 1992–99. National Center for Health Statistics. Vital Health Stat

13(150). 2001

Library of Congress Cataloging-in-Publication Data

Burt, Catharine W.

Trends in hospital emergency department utilization : United States, 1992-99.

p.; cm. — (DHHS publication ; no. (PHS) 2001-1721) (Vital and health

statistics. Series 13, Data from the National Health Care Survey ; no. 150)

By Catharine W. Burt and Linda F. McCaig.

‘‘July 2001.’’

‘‘This report describes trends in hospital emergency department visits in the

United States.’’ Includes bibliographical references.

ISBN 0-8406-0571-4

1. Hospitals—Emergency services—Utilization—United States.

2. Hospitals—Emergency services—Utilization—United States—Statistics.

I. McCaig, Linda F. II. Title. III. Series. IV. Vital and health statistics. Series 13,

Data from the National Health Care Survey; no. 150.

[DNLM: 1. Emergency Services, Hospital—utilization—United States.

2. Hospitalization—trends—United States. 3. Outcome Assessment (Health

Care)—United States. W2 A N148vm no. 150 2001]

RA975.5.E5 B87 2001

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[362.18′0973] 2001044051

For sale by the U.S. Government Printing Office

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Printed on acid-free paper.
Series 13, Number 150

Trends in Hospital

Emergency Department

Utilization: United States,

1992–99

Data From the National

Health Care Survey

DEPARTMENT OF HEALTH AND HUMAN SERVICES

Centers for Disease Control and Prevention

National Center for Health Statistics

Hyattsville, Maryland

November 2001 - Revised

DHHS Publication No. (PHS) 2001-1721
National Center for Health Statistics

Edward J. Sondik, Ph.D., Director

Jack R. Anderson, Deputy Director

Jack R. Anderson, Acting Associate Director for

International Statistics

Jennifer H. Madans, Ph.D., Associate Director for Science

Lawrence H. Cox, Ph.D., Associate Director for Research

and Methodology

Jennifer H. Madans, Ph.D., Acting Associate Director for

Analysis, Epidemiology, and Health Promotion

P. Douglas Williams, Acting Associate Director for Data

Standards, Program Development, and Extramural Programs

Edward L. Hunter, Associate Director for Planning, Budget,

and Legislation

Jennifer H. Madans, Ph.D., Acting Associate Director for

Vital and Health Statistics Systems

Douglas L. Zinn, Acting Associate Director for

Management

Charles J. Rothwell, Associate Director for Information

Technology and Services

Division of Health Care Statistics

Linda K. Demlo, Ph.D., Director

Thomas McLemore, Deputy Director

Irma E. Arispe, Ph.D., Associate Director for Science

Catharine W. Burt, Ed.D., Chief, Ambulatory Care Statistics

Branch

Charles A. Adams, Chief, Technical Services Branch
Contents

Abstract ................................................................................................. 1

Introduction ............................................................................................. 1

Methods ................................................................................................ 2

Results .................................................................................................. 4

Trends in Overall Utilization ............................................................................ 4

Utilization ......................................................................................... 4

Case Mix ......................................................................................... 4

Services Provided ................................................................................... 5

Outcomes ......................................................................................... 6

Trends for Specific Age Groups ......................................................................... 6

Children .......................................................................................... 6

Persons 45–64 Years Old ............................................................................. 7

Seniors ........................................................................................... 7

Discussion ............................................................................................... 8

Overall Utilization .................................................................................... 8

Children ............................................................................................. 10

Racial Disparity Among Seniors ......................................................................... 10

Nature of Racial Disparities ............................................................................ 12

Limitations of Data ................................................................................... 14

Conclusion ............................................................................................... 14

References ............................................................................................... 14

Appendix I

Technical Notes ........................................................................................ 29

Data Collection ..................................................................................... 29

Estimation ......................................................................................... 29

Sampling Errors .................................................................................... 29

Nonsampling Errors ................................................................................. 29

Published and Flagged Estimates ...................................................................... 29

Tests of Significance and Rounding .................................................................... 30

Diagnosis and Injury Groupings ....................................................................... 30

Population Figures and Rate Calculation ................................................................. 31

Appendix II

Definition of Terms ..................................................................................... 33

Terms Relating to the Survey ......................................................................... 33

Terms Relating to the Patient Record Form .............................................................. 33

Revised iii
Figures

1. Annual volume of emergency department visits: United States, 1992–99 ....................................... 4

2. Annual rate of emergency department visits for persons 45 years of age and over by race: United States, 1992–99 .... 5

3. Annual rate of emergency department visits by illness or injury: United States, 1992–99 .......................... 5

4. Annual percent of emergency department visits by selected expected source of payment: United States, 1992–99 ...... 6

5. Annual rate of emergency department visits by selected illness diagnosis categories: United States, 1992–99 ......... 6

6. Annual rate of emergency department visits by selected injury diagnosis categories: United States, 1992–99. ......... 7

7. Annual emergency department visits by selected characteristics: United States, 1992–99 .......................... 7

8. Annual percent of emergency department visits by visit disposition: United States, 1992–99 ....................... 8

9. Annual rates of illness and injury emergency department visits for persons 65 years and over by race:

United States, 1992–99 ............................................................................... 8

10. Annual percent of emergency department visits with five or more drug mentions and rate of emergency department

visits for adverse effects of medical treatment by persons 65 years of age and over: United States, 1992–99 .......... 9

11. Annual rate of hospital admission from the emergency department for persons 65 years of age and over by race:

United States, 1992–99 ............................................................................... 9

12. Annual rate of emergency department visits with a disposition of treated and released for persons 65 years of age

and over by race: United States, 1992–99 ............................................................... 10

13. Percent growth in ambulatory medical care utilization for persons 65 years of age and over by race: United States,

1992–99 .......................................................................................... 11

14. Percent growth in health care services for persons 65 years of age and over by race: United States, 1992–99 ........ 12

15. Growth in Medicare per capita expenditures between 1992 and 1998 on selected medical services for persons

65 years of age and over by race: United States, 1992 and 1998 ............................................ 12

16. Combining emergency department visit incidence and utilization rates for persons 45 years of age and over by race:

United States, 1997–98............................................................................... 13

Detailed Tables

1. Annual rates of emergency department visits with corresponding standard errors by selected patient and hospital

characteristics: United States, 1992–99 ................................................................. 16

2. Annual rates of emergency department visits for illness conditions with corresponding standard errors by selected

patient and hospital characteristics: United States, 1992–99 ................................................. 18

3. Annual visits rates for emergency department utilization for injury conditions by selected patient and hospital

characteristics: United States, 1992–99 ................................................................. 20

4. Mean age and percent distribution of emergency department visits with corresponding standard errors by selected

patient and visit characteristics: United States, 1992–99 ................................................... 22

5. Annual rates of emergency department visits with corresponding standard errors by selected illness and injury

conditions: United States, 1992–99 .................................................................... 24

6. Annual rates of emergency department visits with corresponding standard errors by selected services ordered or

provided: United States, 1992–99 ...................................................................... 26

7. Annual percent of emergency department visits with corresponding standard errors by selected providers seen and

disposition of visit: United States, 1992–99 .............................................................. 28

Appendix Tables

I. Codes used for defining diagnoses and causes of injury .................................................... 30

II. Annual civilian noninstitutionalized population estimates for the United States, 1992–99 ......................... 32

iv Revised
Objectives

This report describes trends in Trends in Hospital Emergency 

hospital emergency department (ED)

visits in the United States. Statistics are Department Utilization:

presented for overall utilization, case

mix of patients, services provided, and

outcome measures. United States, 1992–99

Methods by Catharine W. Burt, Ed.D., and Linda F. McCaig, M.P.H., Division

The data presented in this report of Health Care Statistics

were collected from the National

Hospital Ambulatory Medical Care patients who lack access to primary Survey (NHAMCS) from 1992 through Introduction health care. According to a Government 

1999. To make the data points more Accounting Office study in 1993, over reliable for trend analysis, the data

Hospital emergency departments 40 percent of patients treated in the ED 

were combined to provide 2-year

annual averages for 1993–94, 1995–96, (EDs) account for about lacked a usual source of care (7). 

and

especially large so it was used alone. medical care in the United States. In have difficulty obtaining an appointment 

The 1999 data are the most recent year 1999, there were over 102 million visits in a primary health care setting (5). 

available and are presented separately.

Results

The volume of ED visits in the

United States increased by 14% from

to the EDs of non-Federal, short-stay 

and general hospitals, an increase of 13 

million visits since 1992 (1). From 1997 

through 1999, there was an increase of 

7.8 million visits, which accounts for 

Because many people rely on the ED 

for emergency and nonemergency care, 

the ED visit rate (number of ED visits 

divided by the population) can serve as 

an indicator of the health of our 

1992 through 1999, from 89.8 million to well over half of the observed increases Nation’s population and health care 

102.8 million annually. This increase is since 1992. EDs offer a wide variety of system. If patients have access to 

1997–98. The survey in 1992 was 10 percent of all ambulatory Others, especially Medicaid patients, 

mainly due to an increase in visits for medical care including providing primary care providers and appropriate

illness-related as opposed to

injury-related conditions. Although the stabilization for critically ill patients in medical specialists for good preventive

population rate for ED visits did not their catchment area, rapid processing care and disease management, they may

significantly increase over this time and treatment for injuries from trauma be less likely to make an ED visit (or

period (rates between 35.7 and 37.9 incidents, and medical treatment for less multiple visits) for illness-related

visits per 100 persons), the rate for urgent conditions including chronic and conditions. Similarly, national and local

illness-related visits rose from 21.0 to acute illnesses and minor injuries. focus on safety and injury prevention

24.0 visits per 100 persons (p<0.01). In 1998, the rate of visits to the ED strategies should reduce both the

The most dramatic increases were was 37.3 visits per 100 persons (2); number and severity of injuries treated

observed in the overall visit rate for however there is evidence to suggest in the ED.

black persons 65 years of age and that some persons use the ED on Emergency department use is also

over, which rose by 59% from 45.4 related to a hospital’s ability to provide

visits per 100 persons in 1992 to 72.2 multiple occasions within a year. emergency services. U.S. legislation has

in 1999. For black seniors, both illness According to data from the 1998 

had major effects on ED utilization over

and injury-related visit rates increased National Health Interview Survey the last 15 years. In response to

at a much higher rate compared with (NHIS), 20 percent of

trends for white seniors. noninstitutionalized adults living in the allegations of hospital EDs refusing to

United States made at least one visit to treat patients who were not fully 

Conclusion an ED to seek medical care, and insured, Congress passed the 

Increased volume of ED encounters approximately one-third made multiple Consolidated Omnibus Budget 

for persons 45 years of age and over visits (3). The choice of seeking care at Reconciliation Act (COBRA) of 1985 

was associated with a greater an ED is related to several factors (P.L. 99–292)—the Emergency Medical 

proportion of illness conditions including possession of health insurance, Treatment and Active Labor Act 

presenting to the ED and the use of access to health care providers, and (EMTALA). It requires hospitals that 

more services, medications, and perceived seriousness of condition (4–6). accept Medicare funding to screen all 

mid-level providers. In addition to the ED being frequently patients presenting to the ED for care 

used to evaluate and treat patients for and to provide treatment to stabilize 

Keywords: NHAMCS c emergency acute medical problems and severe emergency medical conditions before 

department visits c diagnoses c injuries, it is also a safety net for transferring or discharging patients from 

trends c health policy the ED. This ‘‘antidumping’’ legislation 

Revised Page 1
Page 2 [ Series 13, No. 150 Revised

holds hospitals liable for paying the bill 

for patients who are not able to pay for 

the cost of care. Because of the 

increased demand of ED care without 

corresponding revenues, many hospitals 

closed their EDs by 1991 (8). About this 

time, the penetration of managed care 

into health insurance started to increase. 

Both public and private managed care 

plans aimed to expand primary care for 

their beneficiaries, which should have 

reduced the need for emergency care. 

Managed care also controlled the 

ever-expanding health care expenditures 

by limiting access to expensive 

emergency care for their enrollees. Most 

plans required prior authorization before 

seeking emergency care unless it is a 

life-threatening condition. The result 

was that even if the patient had health 

insurance, the hospital may not have 

been reimbursed for the care that 

EMTALA required them to provide. 

Under the Balanced Budget Act (BBA) 

of 1997, Medicaid and Medicare 

programs are required to reimburse 

hospitals for emergency care that a 

reasonable person would consider 

necessary. Several States also passed 

legislation that enacted the ‘‘prudent 

layperson’’ standard. Studies have 

shown that between 10 and 40 percent 

of nonurgent ED claims were denied by 

insurance companies, of which over half 

would have met a ‘‘prudent layperson’’ 

standard (9). Since 1997, hospitals 

received more reimbursement for 

emergency care provided to insured 

patients, and there was a commensurate 

rise in the use of both urgent and 

nonurgent services. 

Despite the increased volume of ED 

visits in the United States over the last 

decade, there has been no similar rise in 

the number of hospital EDs to 

accommodate the demand. Therefore, on 

average, most EDs are serving more 

patients on a daily basis now than they 

did in 1992. In addition, a shortage of 

nurses has made staffing problematic, 

which may mean longer waiting times 

and overcrowding (10). But what effect 

does this overcrowding have on how 

patient care is delivered? What 

population subgroups are driving the 

increase in utilization? What differences 

in outcome measures are observed for 

patients treated in EDs? ED encounter 

data from the National Hospital 

Ambulatory Medical Care Survey 

(NHAMCS) can reveal these changing 

patterns of emergency health care. 

The NHAMCS was inaugurated in 

1992 to gather and disseminate 

information about the health care 

provided by hospital EDs and outpatient 

departments (OPDs) to the population of 

the United States. The NHAMCS is part 

of the ambulatory care component of the 

National Health Care Survey that 

measures health care utilization across 

various types of providers including 

physicians, hospitals, home health 

agencies, and nursing homes. This 

report presents national annual estimates 

of hospital emergency department visits 

from 1992 through 1999. Highlights of 

the trends are shown on the adjacent 

page. Trends in overall utilization, case 

mix of patients, services provided, and 

outcome measures are described. 

Another Advance Data report highlights 

ED visits in 1999 (1). For more 

information on the NHAMCS, visit our 

Website: www.cdc.gov/nchs/about/major/ 

ahcd/ahcd1.htm 

Methods 

The data presented in this report 

are from the NHAMCS, a 

national probability sample 

survey conducted annually since 1992 

by the Division of Health Care Statistics 

of the National Center for Health 

Statistics, Centers for Disease Control 

and Prevention. The data from 1992 

through 1999 were analyzed for trends 

in ED utilization. 

The target universe of the 

NHAMCS is in-person visits made in 

the United States to EDs and OPDs of 

non-Federal, short-stay hospitals 

(hospitals with an average stay of less 

than 30 days) or those whose specialty 

is general (medical or surgical) or 

children’s general. The sampling frame 

consisted of hospitals listed in the April 

1991 SMG Hospital Database. The data 

presented in this report are 

representative of utilization statistics for 

hospitals existent in 1991. 

A four-stage probability sample 

design is used in the NHAMCS (11). 

The design involves samples of primary 

sampling units (PSUs), hospitals within 

PSUs, EDs within hospitals and/or 

clinics within outpatient departments, 

and patient visits within EDs and/or 

clinics. The PSU sample consists of 112 

PSUs that comprise a probability 

subsample of the PSUs used in the 

1985–94 National Health Interview 

Survey. The sample consists of 600 

hospitals divided into 16 panels. In any 

one year, only 13 panels are used to 

reduce response burden on the hospitals. 

ED participation rates ranged between 

94 percent and 97 percent. Hospital staff 

were asked to complete Patient Record 

forms for a systematic random sample 

of patient visits occurring during a 

randomly assigned 4-week reporting 

period. The Patient Record form was 

fairly constant from 1992 through 1999, 

but there were some changes in items. 

Only those variables that were constant 

across the years were analyzed. The 

number of Patient Record forms 

completed in any given year ranged 

between 21,103 and 26,706. Because the 

estimates presented in this report are 

based on a sample rather than on the 

entire universe of ED visits, they are 

subject to sampling variability. 

Appendix I includes an explanation of 

sampling errors with guidelines for 

judging the precision of the estimates. 

The standard errors reported here are 

calculated using Taylor approximations 

in SUDAAN, which take into account 

the complex sample design of the 

NHAMCS (12). A weighted 

least-squares analysis was used to 

determine significance of trends at the 

.01 level. Percent increases or decreases 

are mentioned only if the linear trend 

was significant. The % symbol is used 

to indicate percent changes between 

1999 and 1992 (base year) so as not to 

be confused with the referent statistic, 

which may be a percent of ED visits. 

The U.S. Bureau of the Census was 

responsible for data collection. Data 

processing operations and medical 

coding were performed by Analytical 

Sciences Inc., Durham, North Carolina. 

As part of the quality assurance 

procedure, a 10-percent quality control 

sample of survey records was 

independently keyed and coded. Coding 

error rates ranged between 0.1 and 
Revised Series 13, No. 150 [ Page 3

What’s increased since 1992?

Utilization:

+ ED visits overall (up by 14%)

+ Overall population-based visit rates for persons 45–64 years of age (up by 18%) and 65 years of age and over

(up by 17%)

+ Overall visit rates for black persons 65 years of age and over (up by 59%)

Case mix:

+ Percent of visits paid by private HMO insurance (up by 117%), patient-paid (up by 20%), and Medicare

(up by 14%)

+ Visit rates for illness conditions (up by 14%); driven by increased visit rates for persons 25 years of age and over

+ Visit rates for injuries caused by adverse effects of medical treatments (up by 67% for all ages, 103% for

persons 45–64 years of age, and 110% for seniors)

+ Diagnosis rates for symptoms, signs and ill-defined conditions (up by 45%), diseases of the musculoskeletal

system and connective tissue (up by 35%), endocrine and metabolic disorders (up by 51%), and medical

complications (up by 92%)

+ Specific diagnosis visit rates for chest pain (up by 50%), abdominal pain (up by 39%), spinal disorders (up by

43%), drug dependence (up by 84%), psychoses excluding depression (up by 51%), cerebrovascular disease

(up by 53%), and asthma (up by 26%)

+ Visit rates for self-inflicted injuries (up by 147%)

Services provided:

+ Number of medications mentioned at ED visits (mentions up by 34% and drug mention rate up by 20%)

+ Percent of visits with mention of cardiovascular-renal drugs (up by 30%), drugs for the relief of pain

(up by 17%), and central nervous system drugs (up by 32%)

+ Use of CAT scans/MRIs (up by 103%), mental status exams (up by 121%), and EKGs (up by 12%)

+ Administration of intravenous fluids (up by 27%)

+ Use of midlevel providers (up by 56%)

+ Percent of visits where no physician was seen (up by 68%)

Outcomes:

+ Percent released without any planned followup (up by 51%)

+ Percent transferred to another facility (up by 43%)

+ Percent referred to other clinics (up by 28%)

What’s decreased since 1992?

Utilization:

+ Visit rates for injuries for children under 15 years of age (down by 17%) and for persons 15–24 years of age

(down by 15%)

Case mix:

+ Percent of visits paid by Medicaid (down by 23%), percent paid by non-HMO private insurance (down by 19%)

+ Overall visit rates for a primary diagnosis of open wounds (down by 19%), intracranial injuries (down by 67%),

otitis media (down by 24%), noninfectious enteritis and colitis (down by 17%)

+ Visit rates for open wounds among children under 15 years of age (down by 32%)

+ Visit rates for injuries due to falls (down by 9%)

Services provided:

+ Percent of visits treated with respiratory drugs (down by 16%)

+ Use of bladder catheters (down by 25%), nasogastric tubes (down by 50%), and endotracheal intubation

(down by 47%)

+ Use of extremity x rays (down by 29%)

+ Use of residents/interns (down by 49%)
Page 4 [ Series 13, No. 150 Revised

1.7 percent for various survey items 

over the study period. 

Several of the tables in this report 

present data on rates of ED visits. The 

population figures used in calculating 

these rates are U.S. Bureau of the 

Census estimates of the civilian 

noninstitutionalized population of the 

United States as of July 1 in any given 

year, and have been adjusted for net 

underenumeration using the 1990 

National Population Adjustment Matrix. 

Because there were no observed 

significant differences in the crude and 

age-adjusted utilization rates, only the 

crude rates are presented. 

Except for 1992 and 1999, 2 years 

of data were combined to make point 

estimates more reliable (1993–94, 

1995–96, 1997–98). For details on the 

surveys conducted in each year, refer to 

the annual reports (1,2,13–18). 

Appendix II provides information on 

how the drug mentions, race, payment 

source, and injury-related items were 

modified because they varied slightly 

during the study period. 

The visit rates for diagnoses 

presented in this report are based on the 

first-listed or primary diagnosis, which 

was coded according to the 

International Classification of Diseases,

9th Revision, Clinical Modification

(ICD–9–CM) (19). Therapeutic class for 

drug mentions was assigned using the 

National Drug Code Directory (20). 

Injury visits were defined as a visit that 

had any of the following indications that 

the visit may be related to an injury: a 

reason for visit assigned to the injury 

module, a cause of injury assigned to an 

E-code from the ICD–9–CM 

Supplementary Classification of External 

Causes of Injury and Poisoning, or a 

diagnosis assigned to an ICD–9–CM 

code in chapter 17, Injury and 

Poisoning. If the visit was not identified 

as an injury visit, it was defined as an 

illness visit. Patient case mix is defined 

as composition of ED visits in any 

given time period based on patient age, 

type of condition (injury or illness), 

diagnosis, payment source, etc. The 

outcome measures used in this report 

included several disposition options: 

admit to hospital, transfer to other 

facility, refer to other physician/clinic, 

and no followup planned. Admit to 

hospital includes any visits resulting in a 

hospital or critical care unit admission. 

Results 

Trends in Overall

Utilization

Utilization

Between 1992 and 1999, the 

amount of ED utilization increased by 

14 percent, from 89.8 million to 102.8 

million visits annually (figure 1). 

Although the overall population visit 

rate did not change (between 35.7 and 

37.9 visits per 100 persons, p = .33), 

increases in visit rates were observed for 

persons 45–64 years of age (from 25.8 

to 30.5 visits per 100 persons) and for 

persons 65 years of age and over (from 

41.2 to 48.2 visits per 100 persons) 

(table 1). These increases were primarily 

driven by increases in visit rates for 

black persons as no trends were 

observed for white persons in these age 

groups (figure 2). Dramatic increases 

were observed for black seniors from 

45.4 to 72.2 visits per 100 persons. 

Increases were observed in visit rates 

for females in the age groups 25 years 

and over and for males in the age 

groups 45 years and over. No trends 

were observed in overall visit rates by 

geographic region or location of hospital 

(metropolitan statistical area (MSA) or 

non-MSA). 

Case Mix

In addition to the increase in visits 

experienced by EDs in the United 

States, other factors affecting the 

changes in case load of the ED included 

an increase in the average patient age 

from 33.0 to 35.7 years. Older patients 

are more likely to have multiple 

diagnoses and require more medications 

than younger patients. An analysis of the 

case mix found that although visits for 

injuries declined slightly, the amount 

and rate of ED visits for illness 

increased (figure 3). The visit rate for 

illness-related conditions increased 

from 21.0 to 24.0 visits per 100 

persons. The illness visit rate increase 

was driven by increases in the rates 

for persons 25 years of age and over 

(table 2). The injury visit rate declined 

by 17% for persons under 25 years of 

age (table 3). 

The change in case mix of patients 

from younger to older also changed the 

relative distribution of those who paid 

the bills. There were significant linear 

1992 1993-94 1995-96 1997-98 1999 

80 

85 

90 

95 

100 

105 

110 

Nunber of visits in millions 

NOTES: Figures are based on 2-year averages except 1992 and 1999. Trend in volume of visits is significant ( p<.01).

Figure 1. Annual volume of emergency department visits: United States, 1992–99
Revised

trends for all sources except the ‘‘other’’ 

category. Medicare, self-pay, and private 

HMO insurance increased, while 

Medicaid and other private insurance 

decreased from 1992 through 1999 

(table 4). The shift in relative proportion 

of the various payment mechanisms has 

the effect of equalizing expenditures for 

emergency services across payers 

(figure 4). 

Increasing trends were observed for 

all of the leading diagnoses (i.e., chest 

pain, abdominal pain, spinal disorders, 

and asthma) rendered at ED visits 

(table 5). Visits with a primary diagnosis 

in the symptoms, signs, and ill-defined 

category (ICD–9–CM codes 780–799) 

increased by 45% from a rate of 41.7 to 

60.3 visits per 1,000 persons (figure 5). 

Visits with a diagnosis in the 

musculoskeletal system and connective 

tissue category (ICD–9–CM codes 

710–739) increased by 35% from 15.2 

to 20.5 visits per 1,000 persons 

(figure 5). Increasing trends were also 

observed for endocrine and metabolic 

disorders, although the observed 

increase for diabetes (the most frequent 

diagnosis in this category) was not 

significant. Although the visit rates for 

mental disorders as a category did not 

increase significantly, significant 

increases were observed for psychoses 

(excluding major depression) and drug 

dependence and nondependant abuse of 

drugs (table 5). Decreasing trends were 

also found for open wounds, intracranial 

injuries, noninfectious enteritis and 

colitis, and otitis media. Although the 

decline in the overall injury visit rate 

was not significant at the .01 level, there 

was a significant decrease in the visit 

rate for injuries due to falls (from 30.5 

to 27.7 visits per 1,000 persons), which 

accounted for the observed declines in 

open wounds and intracranial injuries 

(figure 6). Troublesome were the 

observed increases in the visit rates for 

self-inflicted injuries (ICD–9–CM codes 

E950–E959, up by 147% from 0.6 to 

1.6 visits per 1,000 persons) and 

problems caused by adverse effects of 

medical treatment (ICD–9–CM codes 

E870–E879 and E930–E949, up by 67% 

from 3.1 to 5.2 visits per 1,000 

persons). These codes include both 

adverse drug events and complications 

from medical and surgical care. 

Series 13, No. 150 [ Page 5

1992 1993-94 1995-96 1997-98 1999 

0 

20 

40 

60 

80 

NOTE: Figures are based on 2-year averages except 1992 and 1999. 

p<.01. Visits per 100 persons 

Black, 65 years and over 

Black, 45-64 years

White, 65 years and over 

White, 45-64 years 

1 

1 

1 

Figure 2. Annual rate of emergency department visits for persons 45 years of age and over

by race: United States, 1992–99

1992 1993-94 1995-96 1997-98 1999 

0 

12 

14 

16 

18 

20 

22 

24 

Visits per 100 persons 

Illness

Injury 

NOTE: Figures are based on 2-year averages except 1992 and 1999. 

p<.01. 1 

1 

Figure 3. Annual rate of emergency department visits by illness or injury: United States,

1992–99

Services Provided

As expected from both the increase 

in patient age and increase in 

illness-related visits, NHAMCS data 

showed an increase in the number of 

medications prescribed, provided, or 

continued at ED visits (figure 7). 

Limiting the number of medications to 

five because the maximum number 

collected varied over the study period, 

the number of drug mentions increased 

by 34 percent, from 118.5 million to 

158.7 million. Correspondingly, the drug 

mention rate rose from 130.8 to 157.1 

medications per 100 ED visits (table 6). 

There was no trend observed in the 

percent of visits where the patient had 

any mention of medication. However, 

there were significant upward trends in 
Page 6 [ Series 13, No. 150

1992 1993-94 1995-96 1997-98 1999 

0 

1

1 5 

10 

15 

20 

25 

30 

35 

Percent of visits NOTES: Figures are based on 2-year averages except 1992 and 1999. Trends shown are significant (p<.01). 

HMO is health maintenance organization. 

Other private insurance 

Medicaid 

Self-pay 

Medicare 

Private HMO

Figure 4. Annual percent of emergency department visits by selected expected source of

payment: United States, 1992–99

1992 1993-94 1995-96 1997-98 1999 

0 

10 

20 

30 

40 

50 

60 

70 

Visits per 1,000 persons 

Ill-defined symptoms 

Musculoskeletal/connective tissue 

Endocrine/metabolic 

NOTES: Figures are based on 2-year averages except 1992 and 1999. Trends shown are significant ( p<.01).

Revised

4.9 percent in 1999). Performance of 

mental status exams doubled from 

5.9 percent to 13.0 percent. Overall use 

of procedures did not change; 

however, the percent of care where 

intravenous fluids were administered 

increased by 27% from 14.4 percent to 

18.3 percent. Declines were observed 

in the percent of cases with a bladder 

catheter, naso-gastric tube/gastric 

lavage, and endotracheal intubation 

(table 6). 

Type of provider seen in the ED 

also changed. In 1992, 3.6 percent of 

patient encounters did not involve a 

physician; however, this increased to 

6.0 percent by 1999 (a rise of 68%). The 

percent of patient encounters involving a 

physician assistant (PA) or nurse 

practitioner (NP) increased by 56% from 

3.9 percent to 6.1 percent, but this was 

primarily driven by an increase in visits 

where a PA was seen. Among physicians 

seen at ED visits, use of residents/ 

interns declined from 13.7 percent to 

7.1 percent. The use of staff 

physicians and registered nurses rose 

slightly. 

Outcomes

The percent of patients admitted to 

the hospital from the ED did not change 

during the study period. In fact, there 

was a slight decline in the percent 

admitted, from 13.5 percent to 

12.9 percent, but it was not significant at 

the .01 level (table 7). However, the 

percent of visits where the patient was 

treated and released from the ED 

without any followup planned increased 

by 51 percent, from 6.0 percent to 

9.0 percent (figure 8). The percent of 

Figure 5. Annual rate of emergency department visits by selected illness diagnosis

categories: United States, 1992–99

the percent of visits with 3, 4, or 5 or 

more drug mentions. Increases were 

observed for several of the major 

therapeutic classes used in the treatment 

of ED patients. The percent of visits 

with mention of cardiovascular-renal 

drugs, drugs used for the relief of pain, 

and central nervous system medications 

rose from 1992 through 1999. 

In addition to increases in 

medication therapy at ED visits, there 

were increases in some diagnostic 

services. Overall, there was no change 

in the percent of visits with imaging, but 

the percent of visits where extremity x 

rays were ordered declined as the use of 

CAT scans and MRIs rose (up 

103 percent from 2.4 percent in 1992 to 

cases transferred to another facility and 

referred to other clinics also increased. 

Trends for Specific Age

Groups

Children

The percent of total ED visits by 

children under 15 years of age declined 

by 15% from 1992 through 1999 

(table 4). For children under 18 years of 

age, the percent of visits with a payment 

source of private HMO insurance 
Revised

increased by 113%, from 8.5 percent to 

18.0 percent. Visits covered by Medicaid 

declined by 15%, from 38.2 percent to 

32.5 percent. The injury visit rate for 

children under age 15 years of age 

declined by 17% (table 3). This decline 

was driven by decreases in the percent 

of visits for open wounds, excluding the 

head, which declined by 31%, from 

6.1 percent to 4.2 percent. As a cause of 

injury in children, unintentional falls 

declined from a rate of 44.5 per 1,000 

children to 30.9 from 1992 through 

1999. This decline accounted for 50% of 

the decline in children’s injury visit 

rates. Increases in ‘‘struck by/against’’ 

causes were offset by slight declines in 

less common causes of childhood 

injuries. The percent of visits for otitis 

media decreased by 21%, from 

12.4 percent to 9.8 percent. The asthma 

ED visit rate, often considered an 

indicator of poor disease management or 

compliance, did not change for children 

under 15 years of age. The percent of 

visits where an antimicrobial was 

prescribed declined from 32.9 percent in 

1993/94 to 28.2 percent in 1999. 

Antimicrobials are no longer the most 

frequent therapeutic class of drugs 

administered at visits by children 

under 15 years of age. The percent of 

visits with prescriptions for pain relief 

drugs increased by 16%, from 

29.4 percent to 34.0 percent making it 

the most frequent drug class used at 

ED visits for children in 1999, while 

prescriptions for respiratory drugs 

decreased by 16%. 

Persons 45–64 Years Old

The percent of total ED visits made 

by persons 45–64 years of age increased 

from 13.9 percent to 17.4 percent 

(table 4), and the visit rate for this group 

increased by 18%, from 25.8 visits per 

100 persons to 30.5 (table 1). Most of 

this increase (85%) was due to increases 

in illness rather than injury conditions. 

Increases in diseases classified in the 

musculoskeletal system and in the 

symptoms, signs, and ill-defined 

conditions categories accounted for 62% 

of the increase in illness conditions. The 

visit rate for ischemic heart disease 

declined, whereas the visit rate for chest 

pain rose. Increases were observed in 

Series 13, No. 150 [ Page 7

1992 1993-94 1995-96 1997-98 1999 

0 

5 

10 

15 

20 

25 

30 

35 

Visits per 1,000 persons 

Open wounds 

Medical complications 

Intracranial injuries 

NOTES: Figures are based on 2-year averages except 1992 and 1999. Trends shown are significant (p<.01). 

Figure 6. Annual rate of emergency department visits by selected injury diagnosis

categories: United States, 1992–99

1992 1993-94 1995-96 1997-98 1999 

0 

100 

125 

150 

175 

200 

Drug mentions per 100 visits 

0 

30 

40 

50 

60 

70 

Percent of visits 

Drug mention rate 

NOTES: Figures are based on 2-year averages except 1992 and 1999. Trends shown are significant (p<.01). 

Percent illness conditions 

Percent patients 45 years and over 

Figure 7. Annual emergency department visits by selected characteristics: United States,

1992–99

medication therapy (table 6). Although 

the overall injury visit rate did not 

increase for this age group, increases 

were observed in the rate of ED visits 

for adverse effects of medical treatment 

(up over 100%). 

Seniors

From 1992 through 1999, the 

relative percent of the civilian 

noninstitutionalized population that was 

65 years of age or over remained the 

same at about 12 percent. However, the 

percent of ED visits made by patients 

65 years of age and over increased by 

8%, from 14.1 percent to 15.2 percent. 

For seniors 65 years of age and over, 

the percent of visits with a payment 

source of private HMO insurance 

increased over 200%, from 2.6 percent 

to 8.1 percent. The percent covered by 
Page 8 [ Series 13, No. 150 Revised

NOTES: Figures are based on 2-year averages except 1992 and 1999. Trends shown are significant ( p<.01).

1992 1993-94 1995-96 1997-98 1999 

0 

10 

20 

30 

40 

50 

Percent of visits 

Referred to other physician/clinic 

No followup planned 

Transferred to other facility 

Figure 8. Annual percent of emergency department visits by visit disposition: United

States, 1992–99

p<.01. 

1992 1993-94 1995-96 1997-98 1999 

0 

10 

20 

30 

40 

50 

60 

Visits per 100 persons 

Illness, black 

Injury, black 

Illness, white 

Injury, white 

1 

1 

1 

1 

NOTE: Figures are based on 2-year averages except 1992 and 1999. 

chest pain rose from 4.5 percent to 

5.9 percent (up 33%). In addition to the 

increases observed in visits with a 

primary diagnosis of chest pain, the visit 

rates for all seniors increased by 99% 

for a primary diagnosis of other 

ill-defined symptoms and 72% for 

cerebrovascular diseases. With the 

observed increase in visits without a 

specific diagnosis, increases were 

observed in the use of imaging (up 

14%), especially CAT scans/MRIs 

(up 102%). The percent of visits by 

seniors with five or more drug mentions 

increased by 59%, from 7.8 percent to 

12.4 percent (figure 10). Much of the 

increase in both of the trends shown in 

figure 10 may be related because sicker 

patients are more likely to receive more 

procedures and more drugs, and adverse 

effects of this care are more likely to 

occur. 

There was a significant increase in 

the rates of black seniors admitted to 

inpatient status from the ED (from 14.8 

visits per 100 persons in 1992 to 25.6 

visits per 100 persons in 1999) 

(figure 11), but no such trend was found 

for white seniors. However, there was 

no trend in the percent of visits resulting 

in hospital admission for either black or 

white seniors (stable at about 40 percent 

of visits). The visit rate for black seniors 

treated and released from the ED (i.e., 

not admitted to the hospital) increased 

by 53%, whereas the increase for white 

seniors was 19% (figure 12). 

Discussion 

Figure 9. Annual rates of illness and injury emergency department visits for persons 65

years of age and over by race: United States, 1992–99

Medicaid decreased by 47%, from 

11.3 percent to 6.0 percent. 

The case mix in terms of percent of 

visits for illness conditions for senior 

black ED patients appeared similar for 

senior white patients. However, from 

1992 through 1999, the illness-visit rates 

for all persons 65 years of age and over 

increased by 21% (table 2) and the 

increase was greater for black than 

white seniors (45% compared with 18%) 

(figure 9). The rate of ED visits for 

black seniors for injuries increased 

dramatically, from 8.8 to 19.0 visits per 

100 persons, an increase of 116% 

(table 3). Although there were no 

observed increases in injury visits 

overall by seniors, the rate of injury 

visits due to adverse effects of medical 

treatment increased by 110 percent, from 

4.8 to 10.2 visits per 1,000 persons 

(figure 10). Visits with a diagnosis of 

Overall Utilization

The cumulative effect of the 

increasing volume of ED encounters 

from 1992 through 1999 without a 

corresponding increase in the number of 

hospitals operating EDs has resulted in 

an ‘‘overcrowding’’ effect (10). In 1992, 

the average ED treated 42.8 patients per 

day, but by 1999 the average ED treated 

47.9 patients per day. Compared with 

hospital EDs in 1992, EDs in 1999 were 

collectively accommodating an 

additional 35,000 patients each day (1). 

Increase in volume by seniors was also 

observed after the 1997 BBA legislated 
Revised

a ‘‘prudent layperson’’ standard for 

Medicaid and Medicare programs. In 

addition to trends in the volume of ED 

patient encounters, this study examined 

trends in population-based utilization 

rates, case mix of conditions, payers, 

services provided, types of providers 

seen, and outcome measures. 

Although overall population-based 

ED utilization rates did not rise, visit 

rates for persons 45–64 years of age and 

65 years of age and over increased. 

Among seniors, visits by black persons 

increased substantially. The case mix of 

patients presenting to the ED shifted 

with a greater percent of visits for 

illness as opposed to injury conditions. 

The percent of visits for illness 

conditions increased as did the 

population-based visit rate. The visit rate 

for injury declined for persons under 25 

years of age. The decline in injury visits 

was driven by a decrease in open 

wounds and contusions. An exception 

was an increase in visit rates for 

medical complications. The rise in 

illness visit rates was driven by an 

increase in cases with symptoms that 

could not be completely diagnosed in 

the ED. This included chest pain and 

other miscellaneous ill-defined 

symptoms and cases with a diagnosis in 

the musculoskeletal area such as spinal 

column disorders like slipped and 

ruptured discs. These two categories 

account for one-quarter of the observed 

increase in illness visit rates. Overall, 

visit rates also increased for diagnoses 

associated with aging such as 

cerebrovascular disease. 

With an increase in cases that could 

not be clearly diagnosed, increases in 

diagnostic services such as CAT 

scans/MRIs and mental status exams 

were observed. Medication therapy 

increased as evidenced by a 19% rise in 

the drug mention rate (number of 

prescribed medications per visit) and a 

27% rise in the administration of 

intravenous fluids. Increases in visits 

with the mention of drugs for pain relief 

correspond with clinical practice 

guidelines that recommend treating 

patient pain more aggressively (21). An 

increase in visits with cardiovascular 

drug mentions is indicative of the 

increasing visits by seniors. But the 

increase in drug mentions is greater than 

Series 13, No. 150 [ Page 9

1992 1993-94 1995-96 1997-98 1999 

0 

4 

6 

8 

10 

12 

14 

16 

Percent of visits 

0 

4 

6 

8 

10 

12 

14 

16 

Visits per 1,000 persons 

Percent with 5 or more drug mentions 

Adverse effects rate 

NOTES: Figures are based on 2-year averages except 1992 and 1999. Trends shown are significant (p<.01). 

Figure 10. Annual percent of emergency department visits with five or more drug mentions

and rate of emergency department visits for adverse effects of medical treatment by

persons 65 years of age and over: United States, 1992–99

1992 1993-94 1995-96 1997-98 1999 

0 

5 

10 

15 

20 

25 

30 

Visits per 100 persons 

White 

Black1 

NOTE: Figures are based on 2-year averages except 1992 and 1999. 

p<.01. 1 

Figure 11. Annual rate of hospital admission from the emergency department for persons

65 years of age and over by race: United States, 1992–99

that expected just by the rise in the 

senior visit rate. 

The last 8 years have seen an 

increase in the utilization of midlevel 

health care providers, perhaps 

substituting for residents/interns or staff 

physicians in an attempt to reduce costs. 

This may be the result of initiatives to 

reduce the number of international 

medical graduates in residency 

training (22). The outcome measures of 

‘‘admit to hospital’’ and ‘‘released with 

no planned followup’’ cover the 

extremes in the spectrum of the types of 

case disposition. There was no observed 

trend in the percent of ED cases 

admitted to inpatient status despite the 

increase in illness to injury case mix. 

Illness visits are twice as likely as injury 

visits to result in hospitalization. More 
Page 10 [ Series 13, No. 150

1992 1993-94 1995-96 1997-98 1999 

0 

10 

20 

30 

40 

50 

60 

Visits per 100 persons 

White 

Black 

NOTES: Figures are based on 2-year averages except 1992 and 1999. Trends shown are significant (p<.01). 

Figure 12. Annual rate of emergency department visits with a disposition of treated and

released for persons 65 years of age and over by race: United States, 1992–99

troubling is the percent of cases that 

were treated and released with no 

planned followup. Protocol suggests that 

continuity of care is best served if there 

is some measure of followup on 

released patients. It may be that the 

overcrowding effect has led to less 

individual attention. Also worrisome is 

the increase in the rate of ED visits for 

adverse effects of medical treatment. 

This includes both complications from 

medical procedures and devices such as 

catheters and infected shunts as well as 

adverse drug events from prescribed 

medication such as allergic reactions 

and inappropriate dosage. The original 

treatment could have occurred in any of 

a variety of health care settings, which 

includes hospital inpatient and outpatient 

settings, physician offices, home health 

care, or nursing homes that include 

skilled nursing facilities. 

Children

The decline in injury visits by 

children 15 years of age and under is 

encouraging. NHAMCS data found that 

this trend was driven by declines in 

visits for open wounds and their leading 

cause, falls. Preventive efforts to reduce 

injuries from falls in sport-related 

activities by wearing appropriate safety 

gear may be having an effect. 

Unpublished data from the NAMCS and 

OPD component of the NHAMCS show 

no rise in visits for falls in other 

ambulatory settings, which would 

support a conclusion that the incidence 

of injuries from falls in children has 

declined as well as the rate of ED visits 

for falls. 

Surprising is the decline in 

percent of children’s visits with an 

expected pay source of Medicaid. 

Unpublished data from the NHAMCS 

OPD and NAMCS data files also show 

declines in the percent of visits by 

children under 18 years of age that 

have an expected source of payment 

of Medicaid (down by 37 percent and 

27 percent, respectively, since 1992). 

Therefore, it appears that children are 

not going to hospital OPDs or 

physician offices in lieu of EDs. The 

State Children’s Health Insurance 

Program (SCHIP) was initiated in 

1997. In the NHAMCS, SCHIP visits 

are coded as Medicaid; therefore, a 

rise in the percent of children’s 

Medicaid visits was expected. 

Additionally, if patients were enrolled 

in a Medicaid-managed care plan, they 

may be counted in the HMO numbers 

rather than Medicaid for this report. 

The decline in visits with 

antimicrobials prescribed since 

1993–94 coincides with the decline in 

visits for otitis media. NAMCS data 

indicate that pediatric antimicrobial 

prescribing decreased from 1989–90 

through 1997–98 and corresponds with 

Revised

increased media attention and provider 

and patient education on the 

inappropriate use of antimicrobials and 

its effect on the development of 

antibiotic resistence (23). 

Racial Disparity Among

Seniors

Why has the ED visit rate 

increased so much more for black 

seniors than for white seniors? 

Examining trend data from other 

health care surveys and data sources 

helps to put this increase in 

perspective. Combining data from the 

NHAMCS and the NAMCS show that 

the racial disparity found in the visit 

rate trends for ambulatory care varies 

by setting (figure 13). The increase in 

rates for black seniors in the ED is 

consistent with increases in their visit 

rates to physician offices. However, 

the opposite is true in hospital 

outpatient departments (OPDs) where 

visit rates for black persons have 

traditionally been higher than visit 

rates for white persons. Since 1992, 

the visit rate for white seniors to the 

OPD increased dramatically whereas 

the black visit rate did not change 

significantly (24). By 1999, black 

seniors 75 years of age and over were 

2.3 times as likely as white seniors to 

make a visit to the OPD, whereas in 

1992, they were 2.7 times as likely. 

The relationship between health 

insurance and ED usage trends is 

complex. The increase in visit rates 

for black seniors does not appear to be 

related to trends in having any health 

insurance coverage, but it may be 

related to what kind of coverage the 

patient has. Data from the National 

Health Interview Survey (NHIS) 

indicate that the percent of persons 

with private health insurance declined 

by 8% between 1994 and 1998 (from 

43.6 percent to 40.3 percent) for black 

seniors and by 13% (from 80.9 percent 

to 70.3 percent) for white seniors (3). 

The percent of persons 65 years of age 

and over with Medicare as their only 

source of health insurance increased 

by 83% for white seniors and by 

30% for black seniors. The 

percent of seniors with Medicaid 
Revised

remained fairly constant from 1994 

through 1998 for white seniors, but 

declined by 28% for black seniors. 

Black seniors were still more likely 

than white seniors to have Medicare 

only (38.1 percent versus 21.8 percent, 

respectively, in 1998). This means that 

they were more likely not to have 

drug coverage (3). Without drug 

coverage, black seniors may be less 

likely to fill the prescriptions they 

have been given (25), which could 

result in a poorer outcome and thus 

more trips to the ED. Black seniors 

were also more likely than white 

seniors to have Medicaid (18.0 percent 

versus 6.4 percent, respectively, in 

1998) (3), which may be related to ED 

use. There may have been changes in 

the percent of physicians who accept 

Medicaid patients over the last 8 

years. In 1999, almost one-quarter of 

office-based physicians did not accept 

new Medicaid-only patients (26). 

Because black seniors were 3 times as 

likely to have Medicaid coverage 

compared with white seniors, they 

may have had more difficulty finding 

new physicians. This may have led to 

more frequent use of the ED for 

primary care. 

Although increases were observed 

for ED utilization and hospital 

admission from the ED for black 

seniors, no similar increase was 

observed in hospital discharge data (27), 

which includes all admissions and not 

just those admitted through the ED. 

Likewise, no increases were observed in 

avoidable hospitalizations for black or 

white seniors over a similar time period 

(1990–98) (28). Avoidable hospitalizations 

can be a keen indicator of gaps in 

access to primary care. Trend data from 

nursing home and hospital discharge 

data sets show decreases in length of 

stay over this time period (29). It may 

be that care is shifting from more costly 

inpatient settings to less costly 

outpatient settings, thus driving the 

increase in ED utilization rates by 

seniors. The early discharge of older 

persons from hospital stays and nursing 

homes may result in more ED visits. 

There is evidence that home health 

care for this age group also increased by 

126% from 1990 through 1998 (28). The 

1997 BBA limited Medicare payments for 

Series 13, No. 150 [ Page 11

SOURCE: NAMCS and NHAMCS. 

NOTE: Based on utilization rates calculated using the U.S. civilian noninstitutionalized population. 

p<.01. 

13 

48

21

59

10 

61

Emergency department 

visits 

Outpatient department 

visits 

Physician office visits 

0 

10 

20 

30 

40 

50 

60 

70 

Percent change 

White Black 

1 

1 

1 

1 

1 

Figure 13. Percent growth in ambulatory medical care utilization for persons 65 years of

age and over by race: United States, 1992–99

home health services after the explosion 

of services per home health patient in 

the early 1990s (30). It is possible that 

beginning in 1998, seniors who were 

denied home health services made more 

frequent trips to the ED. Data from the 

National Home and Hospice Care 

Survey (NHHCS) show that the use of 

home health care from 1992 through 

1998 increased by 116% for white 

seniors (56.3 to 121.5 per 1,000 seniors) 

and 213% for black seniors (68.0 to 

212.9 per 1,000 persons) (figure 14). In 

1998, black seniors were nearly twice as 

likely as white seniors to use home 

health services (29). 

The method by which visit rates for 

the NHAMCS are calculated may affect 

the racial disparities in the observed 

trends. The NHAMCS traditionally uses 

the civilian noninstitutionalized 

population (CNP) estimates whereas the 

other component surveys of the National 

Health Care Survey use the total civilian 

population (CP) estimates. Data from 

the National Nursing Home Survey 

(NNHS) showed that there was an 

increase in the rate of black seniors 

using nursing homes and a decrease in 

the use rate by white seniors. Thus there 

is now parity between the two races in 

nursing home utilization (29). But 

because nursing home residents are not 

included in the CNP, a disproportionately greater number of black seniors 

may be excluded from the ED visit rate 

denominator and included in the 

numerator, thus artificially increasing 

the ED rates. Unfortunately, the 

NHAMCS did not start collecting 

information on whether the patient 

resides in a nursing home until 2001. 

The CNP for both black and white 

seniors increased by about 4.5% 

between 1992 and 1999. However, the 

CP increased by 11% for black seniors 

and 6% for white seniors. The 

differential increase in the use of 

nursing homes made the ED visit rate 

for black seniors grow more steeply 

than that for white seniors. However, if 

the CP is used as the ED visit rate 

denominator, then the increase is 49% 

for black seniors compared with 12% 

for white seniors, as opposed to 59% 

and 13%, respectively, using the CNP as 

the denominator. Therefore, using the 

CNP rather then the CP only accounts 

for 17% of the observed increase in the 

ED visit rates for black seniors. 

Because almost 80% of care in the 

ED for persons 65 years of age and over 

is paid by Medicare, examining data for 

Medicare beneficiaries is helpful in 

corroborating trends observed from the 

NHAMCS. Data from the Health Care 

Financing Agency (HCFA) indicate that 

the per capita expenditures for outpatient 
Page 12 [ Series 13, No. 150 Revised

NOTE: Based on utilization rates calculated using the U.S. civilian population. 

p<.01. 

1992-98. 

White Black 

1 

2 

1 

1 

1 

1 

1 

1 

12 8 

116 

16 

49 

14 

213 

23 

Emergency 

department 

visits 

Hospital stays Home health 

discharges 

Nursing 

home 

discharges 

0 

50 

100 

150 

Percent change 

200 

250 

research looking at 1997 and 1998

Medicare data has found that senior

black beneficiaries were more likely

than white beneficiaries to be in poorer

health, have disabling chronic diseases

such as diabetes and hypertension, and

have limitations in their activities of

daily living (ADLs) (32,33). Research

also shows that race differences persist

despite differences in income. Medicare

beneficiaries with lower patient income

make fewer ambulatory physician visits,

more ED visits, less use of MRIs, less

use of mammography, and have more

amputations (most frequently a

complication of diabetes). The

income-adjusted black:white ratios for

these services were 0.93 for ambulatory

physician visits, 1.37 for ED visits, 0.95

for MRIs, 0.75 for mammography, and

3.30 for lower limb amputation (32).

Mortality data from 1997 show that

black persons 65 years of age and over

are more likely than white persons to

die from diseases of the heart and

cerebrovascular diseases. However,

Medicare data show that rates of

common procedures for treating these

diseases are higher among white

beneficiaries than among black

beneficiaries (e.g., coronary artery

Figure 14. Percent growth in health care services for persons 65 years of age and over by

race: United States, 1992–99

services (which include both ED and OPD

settings) between 1992 and 1998

increased by 49% for black enrollees

compared with 34% for white enrollees

(31). This differential increase is

consistent with most other covered

services (figure 15). By 1998, the per

capita expenditures for outpatient services

were $760.27 for black seniors compared

with $452.64 for white seniors.

Racial disparities for

seniors (black vs. white) in

percentage growth in other

health care measures,

1992–1999

+ ED utilization growth

(59% vs. 13%)

+ Physician office utilization

growth (61%vs. 21%)

+ Home health discharges

(213% vs. 116%)

+ Nursing home discharges

(23% vs. 16%)

+ Civilian population increase

for seniors (11% vs. 6%)

+ Medicare expenditures for

outpatient services (49% vs.

34%)

Nature of Racial

Disparities

Given that several broad measures

point to disparate increases in health

care utilization for black persons, other

research can show the nature of racial

disparity in the health of seniors. Recent

SOURCE: Health Care Financing Administration (HCFA) based on 1998 dollars. 

Includes both emergency department and outpatient department services. 

All services Outpatient Physician Hospital stay Home health care 

0 

10 

20 

30 

40 

50 

60 

Percent change 

White Black 

1 

1 

Figure 15. Growth in Medicare per capita expenditures between 1992 and 1998 on selected

medical services for persons 65 years of age and over by race: United States, 1992 and

1998
Revised

bypass graft, coronary angioplasty, 

sonography of the carotid artery, and 

thromboendarterectomy). Gornik (32) 

concludes that there are barriers other 

than insurance coverage that influence 

racial disparities in the use of specific 

types of services. Elderly black persons 

as well as the least affluent Medicare 

beneficiaries have lower rates of 

preventive services and higher rates of 

procedures associated with poor 

outcomes in chronic disease 

management (e.g., lower limb 

amputation). 

In examining racial disparities, it is 

important to know if much of the 

utilization is from the same set of 

people or the usage is spread across 

many persons. Because the NHAMCS is 

a record-based survey that does not 

collect patient identifiers, it is 

impossible to determine which visits are 

made by the same patients. Data from 

the 1992 NHAMCS (which had an item 

on initial or follow-up visit) found that 

about 7 percent of ED visits were 

follow-up visits from a previous ED 

encounter (13). However, there could 

also be other visits from frequent users 

of the ED that are not necessarily 

follow-up visits. One study from an 

urban university hospital that excluded 

scheduled return visits found that 

frequent ED users (four or more visits 

within 1 year) were more likely to be 

black and more likely to have Medicare 

or Medicaid as payment sources (34). 

Over one-quarter of their frequent 

users indicated that they had difficulty 

seeing a primary care physician. 

Frequent users were more likely than 

diagnoses indicate that seniors are 

more likely to make multiple 

unscheduled visits. 

Incidence data on ED usage from 

the NHIS, a population-based survey, 

can shed light on persons who use the 

ED multiple times within a year and 

disparity in ED utilization at a national 

level. Analyzing combined data from the 

1997 and 1998 NHIS sample adult files 

revealed that there were no racial 

differences in the percent of people who 

made only one ED visit during the year, 

but there was a disparity in the percent 

who made multiple (two or more) visits. 

Multiple ED visits were made by 

7.4±.28 percent of white seniors and 

11.4±.97 percent of black seniors. Black 

seniors were 50 percent more likely than 

white seniors to make multiple ED visits. 

Using the NHIS data to help indicate the 

volume of visits attributable to single or 

multiple ED users, figure 16 compares the 

ED utilization rates for persons 45–64 

years of age and persons 65 years of age 

and over. It demonstrates that the bulk of 

ED utilization is attributable to a relatively 

small percent of persons. 

The first segment in the bars shown 

in figure 16 shows that part of the ED 

visit rate attributable to persons who 

made only one ED visit (the NHIS 

incidence rate for single ED visits); the 

second segment shows the first visit for 

persons who made multiple visits (the 

NHIS incidence rate for multiple users). 

Series 13, No. 150 [ Page 13

The total length of the bar represents the 

NHAMCS ED utilization rate. 

Subtraction provides the third and last 

segment of the bar, which represents the 

‘‘extra’’ ED visits made by persons who 

made multiple visits (i.e., those visits 

beyond their first visit). But not all of 

these ‘‘extra’’ visits are actually made 

by the kinds of persons who are 

surveyed by the NHIS. The extra visits 

would also include visits by persons 

living in institutional settings like 

nursing homes, international visitors 

who may require medical care while in 

the United States, and the homeless. As 

shown before, persons residing in 

nursing homes make visits to the ED, 

and there are proportionately greater 

numbers of black persons living in 

nursing homes compared with white 

persons. Unpublished logistic regression 

analysis from the 1997/98 NHIS 

modeling frequent ED users (persons 

with more than one ED visit within the 

last 12 months) versus one-time users 

(persons with only one ED visit within 

the last 12 months) for adults over age 

18 years, found that patient age was 

unrelated to frequent ED use after 

entering other variables into the model 

such as race, sex, having diabetes, and 

having hypertension. After adjusting for 

all these factors, black patients were 

more likely than white patients to make 

multiple visits (OR=1.44:95% 

CI;1.29,1.61), as were females 

the general ED population at that 

hospital to be admitted to the hospital 

on the date of their participation in the 

study (28 percent versus 16 percent). 

In a study of early returns 

(unscheduled return visits within 3 

days of the initial visit) to another 

university ED, researchers found that 

patients with an initial diagnosis of 

dehydration are at higher risk for an 

early return and an ultimate admission 

compared with patients with other 

initial diagnoses (35). Other frequent 

diagnoses in the early return group 

included septicemia, pneumonia, and 

asthma. These studies were not limited Figure 16. Combining emergency department visit incidence and utilization rates for

to seniors, but the nature of the persons 45 years of age and over by race: United States, 1997–98

Source: Based on incidence rates from National Health Interview Survey (NHIS) and utilization rates from National Hospital 

Ambulatory Medical Care Survey (NHAMCS). 

45-64 years 

White 

Black 

65 years and 

over 

White 

Black 

0 0 40 60 80 

Visits per 100 persoms 

Visits for persons with only one 

emergency department visit 

First visits for persons 

with multiple emergency 

department visits 

Extra visits 

10.8 

12.7 

14.3 

14.9 

5.0 

10.2 

7.4 

11.4 

10.0 

33.9 

23.7 

45.0 

2
Page 14 [ Series 13, No. 150

(OR=1.28:95% CI;1.17,1.40). Patients

with diabetes and hypertension were

also more likely to make multiple ED

visits. When only persons 65 years of

age and over were included in the full

model, black seniors were 38% more

likely than white seniors to make

multiple visits (OR=1.38:95%

CI;1.09,1.74). The theory that many of

the ‘‘extra’’ visits for older black

patients are from people who are not

captured in the NHIS is supported by

the fact that age was not a significant

predictor of making multiple ED visits.

Future NHAMCS data containing

estimates of ED visits by nursing home

residents should help explain some of

the observed disparities.

Evidence of racial disparity

in health of persons 65

years of age and over

+ Black seniors were 50% more

likely than white seniors to

make multiple ED visits

within a 12-month period.

+ After adjusting for age, sex,

and history of chronic

conditions, black persons were

38% more likely than white

persons to make multiple ED

visits.

+ Income-adjusted utilization of

health services indicate poorer

disease management among

black persons compared to

white persons.

Limitations of Data

Limitations of the current study

include possible nonsampling error

related to data abstraction. Because the

data are abstracted from medical

records, abstractors may not be able to

differentiate between whether an HMO

member’s health plan was a Medicare,

Medicaid, or private insurance plan.

Therefore, the drop in Medicaid visits in

each age group studied may be an

artifact of miscoding. However, the

number of Medicaid recipients has

declined slightly between 1992 and

1999. Using Current Population Survey

(CPS) estimates of Medicaid enrollees

in the denominator (36) and ED visits

with an expected source of payment of

Medicaid in the numerator reveals that

there was no net per capita decline in

ED use for Medicaid enrollees. The rate

was 61.2 ED visits per 100 enrollees in

1992, 69.5 in 1993–94, and 61.3 in

1999.

Another limitation of NHAMCS

data for examining ED utilization trends

is that the data only capture visits made

to the ED, not the number of times

ambulance patients are diverted away

from one hospital and sent to another.

At approximately 14 percent of ED

visits in 1999, the patient arrived by

ambulance (1). However, trends cannot

be analyzed for this because the

NHAMCS did not publish mode of

patient arrival data prior to 1999. Data

from other sources show that although

increased volume is one factor in

ambulance diversions, more urban EDs

cite full critical care beds as the main

reason for the increased number of

diversions (37). The ability of EDs to

accept ambulance cases depends on the

availability of acute and critical care

beds. The number of staffed critical care

beds in community hospitals declined by

17% since 1992 (37). Reductions in

inpatient bed capacity, more tightly

managed staffing levels, on-call

physician availability, and nursing

shortages have resulted in inpatient beds

not always being available for ED

patients. An insufficient number of

inpatient beds for critical care ED

patients causes a gridlock and results in

ambulance diversions. The NHAMCS

plans to collect ambulance diversion

information in future surveys.

Conclusion

I

n summary, an increase in the U.S.

population with no increase in the

number of EDs led to an increased

volume in non-Federal, general, and

short-stay hospitals EDs. More than half

of the increased volume in ED use

occurred since the 1997 Balanced

Budget Act was enacted requiring public

Revised

health insurance to cover ED visits that

meet the ‘‘prudent layperson’’ standard.

From 1992 through 1999, persons 45

years of age and over increased their

use of EDs annually. The increase was

driven by illness as opposed to injury

conditions, especially an increase in

visits for ill-defined symptoms and

musculoskeletal diseases. Increases in

diagnostic services and medication

therapy accompanied the increase in

volume of older patients. The increased

ED visit volume was also accompanied

by an increase in the use of midlevel

providers.

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for Health Statistics. 2001. 

http://www.cdc.gov/nchs/data/ad/ 

ad322.pdf 

27. Unpublished NHDS data. 

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2001:20(2);225–232. 

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MJ. Trend data on medical encounters: 

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services: Potential causes, plausible 

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34.Lucas RH, Sanford SM. An analysis of 

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urban university hospital. Ann Emerg 

Med November 1998; 32:563–568. 

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Williams BC. Initial emergency 

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trendwatch/twmarch2001.asp 
Page 16 [ Series 13, No. 150 Revised

Table 1. Annual rates of emergency department visits with corresponding standard errors by selected patient and hospital characteristics:

United States, 1992–99

Percent

Selected patient change

and hospital characteristics 1992 1993–94 1995–96 1997–98 1999 since 1992

Number of visits per 100 persons per year1,2

All visits .............................. 35.7 35.7 35.5 36.4 37.9 6

Patient characteristics

Age:

Under 15 years ......................... 39.9 39.9 36.6 36.0 36.7 –8

15–24 years ........................... 43.1 43.4 41.4 41.0 40.9 –5

25–44 years ........................... 33.5 33.7 34.9 35.8 38.5 15

45–64 years ........................... 25.8 25.4 26.4 28.7 30.5 @18

65 years and over ........................ 41.2 41.3 43.3 47.0 48.2 @17

Sex and age:

Female .............................. 36.1 36.7 36.4 37.8 38.9 8

Under 15 years ........................ 37.0 37.3 34.6 33.9 34.6 –7

15–24 years .......................... 46.6 47.7 45.3 45.7 44.9 –4

25–44 years .......................... 34.0 34.4 35.9 37.1 39.6 @17

45–64 years .......................... 26.3 26.4 27.5 29.2 31.7 @20

65 years and over ...................... 43.0 42.7 44.0 48.9 50.0 @16

Male ................................ 35.3 35.5 34.9 35.4 36.6 4

Under 15 years ........................ 42.7 42.5 38.6 38.0 38.0 –11

15–24 years .......................... 39.8 39.0 37.6 36.3 37.1 –7

25–44 years .......................... 33.0 33.0 33.8 34.5 37.4 13

45–64 years .......................... 25.2 24.4 25.3 28.2 29.2 @16

65 years and over ...................... 38.7 39.3 42.3 44.4 45.9 @19

Race and age:

White ............................... 33.6 33.4 32.9 33.7 35.2 5

Under 15 years ........................ 37.5 37.5 34.1 33.4 34.3 –9

15–24 years .......................... 42.2 41.6 39.0 38.5 38.5 –9

25–44 years .......................... 30.4 30.7 31.7 32.4 35.2 16

45–64 years .......................... 24.3 23.6 23.9 25.8 27.9 15

65 years and over ...................... 41.0 40.4 42.2 45.3 46.3 13

Black ................................ 54.5 56.7 57.8 61.0 60.4 11

Under 15 years ........................ 57.3 56.6 56.9 54.6 51.8 –10

15–24 years .......................... 56.4 62.9 61.3 62.7 60.9 8

25–44 years .......................... 59.6 60.1 62.8 65.4 67.8 14

45–64 years .......................... 42.3 44.7 51.1 56.8 55.6 @31

65 years and over ...................... 45.4 54.6 58.9 71.4 72.2 @59

Other race ............................ 20.6 18.9 19.7 17.9 22.3 8

Hospital characteristics

Geographic region:

Northeast ............................. 33.9 37.0 37.1 37.4 37.0 9

Midwest .............................. 42.0 40.2 39.7 38.6 40.1 –5

South ............................... 35.0 35.4 35.2 37.0 40.4 15

West ................................ 31.5 30.3 30.2 32.1 31.5 0

Hospital location:

MSA area3 ............................ 36.1 25.5 24.5 35.0 36.1 0

Non-MSA area3 ......................... 34.3 36.8 39.9 42.0 44.5 30
Revised Series 13, No. 150 [ Page 17

Table 1. Annual rates of emergency department visits with corresponding standard errors by selected patient and hospital characteristics:

United States, 1992–99—Con.

Percent

Selected patient change

and hospital characteristics 1992 1993–94 1995–96 1997–98 1999 since 1992

Standard error of rates

All visits .............................. 1.32 1.30 1.07 1.10 1.65 . . .

Patient characteristics

Age:

Under 15 years ......................... 2.54 1.88 1.43 1.51 2.18 . . .

15–24 years ........................... 2.11 1.70 1.60 1.65 2.21 . . .

25–44 years ........................... 1.50 1.27 1.10 1.17 1.69 . . .

45–64 years ........................... 1.11 0.96 0.87 1.00 1.54 . . .

65 years and over ........................ 1.72 1.68 1.67 1.63 2.59 . . .

Sex and age:

Female .............................. 1.38 1.38 1.11 1.12 1.72 . . .

Under 15 years ........................ 2.27 1.80 1.37 1.55 1.90 . . .

15–24 years .......................... 2.57 2.11 1.83 1.85 3.09 . . .

25–44 years .......................... 1.58 1.33 1.18 1.24 1.97 . . .

45–64 years .......................... 1.31 1.16 0.99 1.04 2.13 . . .

65 years and over ...................... 1.91 1.83 1.80 1.81 4.17 . . .

Male ................................ 1.34 1.29 1.09 1.12 1.67 . . .

Under 15 years ........................ 2.91 2.06 1.62 1.59 2.47 . . .

15–24 years .......................... 1.98 1.55 1.63 1.61 2.12 . . .

25–44 years .......................... 1.61 1.36 1.13 1.21 1.83 . . .

45–64 years .......................... 1.16 0.88 0.94 1.14 1.52 . . .

65 years and over ...................... 1.76 1.75 1.91 1.63 2.73 . . .

Race and age:

White ............................... 1.43 1.39 1.23 1.25 1.79 . . .

Under 15 years ........................ 2.29 1.89 1.55 1.51 2.23 . . .

15–24 years .......................... 2.24 1.91 1.85 1.94 2.37 . . .

25–44 years .......................... 1.43 1.32 1.20 1.32 1.78 . . .

45–64 years .......................... 1.11 1.01 0.95 1.07 1.64 . . .

65 years and over ...................... 1.82 1.85 1.79 1.78 2.61 . . .

Black ................................ 3.84 2.83 2.70 2.59 3.39 . . .

Under 15 years ........................ 7.82 4.04 3.64 3.75 4.97 . . .

15–24 years .......................... 5.05 3.38 3.24 3.28 3.98 . . .

25–44 years .......................... 5.51 3.35 3.36 2.94 4.09 . . .

45–64 years .......................... 4.34 2.70 3.03 3.24 3.62 . . .

65 years and over ...................... 5.08 3.86 4.44 4.85 7.53 . . .

Other race ............................ 3.94 3.47 3.35 2.21 3.05 . . .

Hospital characteristics

Geographic region:

Northeast ............................. 2.22 2.73 2.10 2.18 3.19 . . .

Midwest .............................. 3.49 2.84 2.34 2.28 3.58 . . .

South ............................... 2.10 2.27 2.07 1.99 3.16 . . .

West ................................ 2.97 2.56 1.73 2.39 3.32 . . .

Hospital location: . . .

MSA area3 ............................ 1.55 1.56 1.15 1.24 1.75 . . .

Non-MSA area3 ......................... 3.32 3.28 3.77 3.31 4.64 . . .

@ Trend is significant (p<.01).

. . . Category not applicable.

1Based on U.S. Bureau of the Census monthly postcensal estimates of the civilian noninstitutionalized population of the United States as of July 1 of each year. Figures are consistent with the

downloadable series, ‘‘U.S. Population Estimates by Age, Sex, Race, and Hispanic Origin: 1980 to 1999’’ available at the Census Internet site: http://ftp.census.gov/population/www/estimates/

nat_90s_4.html. Figures have been adjusted for net underenumeration using the 1990 National Population Adjustment Matrix.

2Regional estimates were provided by the Division of Health Interview Statistics. (DHIS), National Center for Health Statistics, and are also based on U.S. census estimates of the civilian

noninstitutionalized population as of July 1 each year. DHIS estimates differ slightly from monthly postcensal estimates because of differences in the adjustment process.

3MSA is metropolitan statistical area.
Page 18 [ Series 13, No. 150 Revised

Table 2. Annual rates of emergency department visits for illness conditions with corresponding standard errors by selected patient and

hospital characteristics: United States, 1992–99

Percent

Selected patient and change

hospital characteristics 1992 1993–94 1995–96 1997–98 1999 since 1992

Number of visits per 100 persons per year1,2

All illness visits .......................... 21.0 20.9 21.8 23.0 24.0 @14

Patient characteristics

Age:

Under 15 years ......................... 23.6 23.9 22.4 22.4 22.8 –4

15–24 years ........................... 21.6 22.1 22.1 22.4 22.6 5

25–44 years ........................... 18.3 18.3 20.1 21.6 23.1 @26

45–64 years ........................... 16.6 15.9 17.6 19.0 20.6 @24

65 years and over ........................ 29.9 29.3 31.8 35.0 36.0 @21

Sex and age:

Female .............................. 23.3 23.4 24.4 25.7 26.6 @14

Under 15 years ........................ 23.1 23.5 22.4 22.7 22.4 –3

15–24 years .......................... 29.5 30.3 30.2 30.3 30.1 2

25–44 years .......................... 21.2 21.6 23.9 25.2 26.6 @25

45–64 years .......................... 18.0 17.1 18.8 20.0 21.8 @21

65 years and over ...................... 52.9 52.3 57.2 67.2 72.1 @36

Male ................................ 18.6 18.4 19.1 20.1 21.2 14

Under 15 years ........................ 24.2 24.2 22.3 22.1 23.2 –4

15–24 years .......................... 13.6 13.9 14.1 14.7 15.2 12

25–44 years .......................... 15.4 14.9 16.2 17.9 19.6 @27

45–64 years .......................... 15.1 14.5 16.4 18.0 19.3 @28

65 years and over ...................... 46.0 46.2 52.5 56.7 58.0 @26

Race and age:

White ............................... 19.1 19.0 19.5 20.7 21.9 15

Under 15 years ........................ 20.7 21.4 19.6 19.7 20.6 0

15–24 years .......................... 19.5 20.4 19.3 20.1 20.3 4

25–44 years .......................... 15.9 15.9 17.5 19.0 20.5 @29

45–64 years .......................... 15.3 14.3 15.5 16.7 18.6 @21

65 years and over ...................... 29.4 28.4 30.6 33.2 34.8 @18

Black ................................ 37.0 36.9 40.2 42.2 41.1 11

Under 15 years ........................ 41.3 38.3 38.9 39.2 36.3 –12

15–24 years .......................... 35.7 36.3 40.3 39.7 39.1 10

25–44 years .......................... 37.3 37.3 40.7 42.9 44.1 18

45–64 years .......................... 30.0 31.4 37.8 41.1 39.8 @32

65 years and over ...................... 36.6 41.8 48.5 58.0 53.2 @45

Other race ............................ 12.3 11.7 12.2 10.7 13.5 10

Hospital characteristics

Geographic region:

Northeast ............................. 19.1 21.0 22.8 23.4 23.1 21

Midwest .............................. 24.5 23.1 23.9 24.1 25.4 4

South ............................... 21.6 21.4 22.3 24.1 26.0 20

West ................................ 18.1 17.7 17.8 19.3 19.7 9

Hospital location:

MSA3 ............................... 21.2 20.7 21.1 22.1 23.1 9

Non-MSA3 ............................ 20.4 21.7 24.6 26.4 27.4 34
Revised Series 13, No. 150 [ Page 19

Table 2. Annual rates of emergency department visits for illness conditions with corresponding standard errors by selected patient and

hospital characteristics: United States, 1992–99—Con.

Percent

Selected patient and change

hospital characteristics 1992 1993–94 1995–96 1997–98 1999 since 1992

Standard error of rates

All illness visits .......................... 0.85 0.83 0.69 0.73 1.10 . . .

Patient characteristics

Age:

Under 15 years ......................... 1.91 1.29 9.19 0.81 1.30 . . .

15–24 years ........................... 1.24 1.04 0.76 0.70 1.27 . . .

25–44 years ........................... 1.00 0.92 0.69 0.65 1.27 . . .

45–64 years ........................... 1.11 1.00 0.75 0.71 1.31 . . .

65 years and over ........................ 1.57 1.29 1.10 1.54 1.92 . . .

Sex and age:

Female .............................. 0.96 0.97 0.77 0.82 1.20 . . .

Under 15 years ........................ 1.77 1.29 1.02 1.23 1.55 . . .

15–24 years .......................... 1.88 1.58 1.36 1.36 1.81 . . .

25–44 years .......................... 1.08 0.92 0.84 0.91 1.25 . . .

45–64 years .......................... 1.06 0.88 0.78 0.80 1.40 . . .

65 years and over ...................... 2.53 2.47 2.43 2.72 4.06 . . .

Male ................................ 0.81 0.72 0.64 0.66 1.08 . . .

Under 15 years ........................ 2.13 1.30 1.09 1.08 1.82 . . .

15–24 years .......................... 0.91 0.68 0.78 0.81 1.07 . . .

25–44 years .......................... 0.92 0.72 0.63 0.69 1.04 . . .

45–64 years .......................... 0.75 0.61 0.67 0.77 1.17 . . .

65 years and over ...................... 2.36 2.21 2.42 2.22 3.52 . . .

Race and age:

White ............................... 0.88 0.87 0.76 0.83 1.17 . . .

Under 15 years ........................ 1.59 1.20 1.01 1.07 1.59 . . .

15–24 years .......................... 1.25 1.14 1.02 1.16 1.34 . . .

25–44 years .......................... 0.84 0.76 0.74 0.83 1.09 . . .

45–64 years .......................... 0.76 0.70 0.68 0.77 1.21 . . .

65 years and over ...................... 1.38 1.39 1.34 1.43 1.94 . . .

Black ................................ 2.78 2.01 2.04 1.86 2.46 . . .

Under 15 years ........................ 6.39 2.89 2.88 3.07 3.68 . . .

15–24 years .......................... 3.99 2.43 2.37 2.21 2.94 . . .

25–44 years .......................... 3.37 2.27 2.31 1.91 2.93 . . .

45–64 years .......................... 3.45 2.29 2.67 2.43 2.95 . . .

65 years and over ...................... 4.30 3.14 3.84 4.11 5.35 . . .

Other race ............................ 2.48 2.42 2.07 1.32 1.93 . . .

Hospital characteristics

Geographic region:

Northeast ............................. 1.38 1.60 1.39 1.47 2.03 . . .

Midwest .............................. 2.42 1.74 1.46 1.43 2.38 . . .

South ............................... 1.27 1.55 1.38 1.40 2.16 . . .

West ................................ 1.78 1.65 1.02 1.44 2.05 . . .

Hospital location:

MSA3 ............................... 0.98 0.98 0.72 0.81 1.15 . . .

Non-MSA3 ............................ 2.14 1.94 2.31 2.18 3.12 . . .

@ Trend is significant (p<.01).

. . . Category not applicable.

1Based on U.S. Bureau of the Census monthly postcensal estimates of the civilian noninstitutionalized population of the United States as of July 1 of each year. Figures are consistent with the

downloadable series, ‘‘U.S. Population Estimates by Age, Sex, Race, and Hispanic Origin: 1980 to 1999’’ available at the Census Internet site: http://ftp.census.gov/population/www/estimates/

nat_90s_4.html. Figures have been adjusted for net underenumeration using the 1990 National Population Adjustment Matrix.

2Regional estimates were provided by the Division of Health Interview Statistics (DHIS), National Center for Health Statistics, and are also based on U.S. census estimates of the civilian

noninstitutionalized population as of July 1 each year. DHIS estimates differ slightly from monthly postcensal estimates because of differences in the adjustment process.

3MSA is metropolitan statistical area.
Page 20 [ Series 13, No. 150 Revised

Table 3. Annual visit rates for emergency department utilization for injury conditions by selected patient and hospital characteristics:

United States, 1992–99

Percent

Selected patient and change

hospital characteristics 1992 1993–94 1995–96 1997–98 1999 since 1992

Number of visits per 100 persons per year1,2

All injury visits .......................... 14.7 14.8 13.7 13.5 13.8 –6

Patient characteristics

Age:

Under 15 years ......................... 16.3 16.1 14.3 13.6 13.6 @–17

15–24 years ........................... 21.6 21.3 19.3 18.5 18.3 @–15

25–44 years ........................... 15.2 15.4 14.8 14.2 15.4 2

45–64 years ........................... 9.2 9.6 8.8 9.7 9.9 8

65 years and over ........................ 11.3 12.0 11.5 12.1 12.2 8

Sex and age:

Female .............................. 12.75 12.98 11.9 11.85 12.33 –3

Under 15 years ........................ 14.0 13.7 12.2 11.2 12.2 @–12

15–24 years .......................... 17.1 17.5 15.1 15.5 14.8 –14

25–44 years .......................... 12.8 12.8 12.1 11.9 13.1 2

45–64 years .......................... 8.3 9.2 8.7 9.2 9.9 19

65 years and over ...................... 22.5 23.6 22.9 24.7 23.7 5

Male ................................ 16.7 16.7 15.6 15.2 15.4 –8

Under 15 years ........................ 18.5 18.3 16.2 15.8 14.8 @–20

15–24 years .......................... 26.2 25.2 23.5 21.5 21.9 @–16

25–44 years .......................... 17.6 18.2 17.7 16.6 17.9 1

45–64 years .......................... 10.1 9.9 8.8 10.2 9.9 –2

65 years and over ...................... 14.2 16.0 16.3 17.7 20.5 @44

Race and age:

White ............................... 14.56 14.46 13.44 13.02 13.29 –9

Under 15 years ........................ 16.8 16.1 14.5 13.7 13.6 @–19

15–24 years .......................... 22.7 21.3 19.7 18.5 18.1 @–20

25–44 years .......................... 14.5 14.8 14.2 13.4 14.6 1

45–64 years .......................... 9.0 9.2 8.4 9.0 9.3 3

65 years and over ...................... 11.6 12.1 11.6 12.0 11.6 1

Black ................................ 17.54 19.83 17.63 18.74 19.31 10

Under 15 years ........................ 16.0 18.4 15.0 15.5 15.6 –2

15–24 years .......................... 20.7 26.6 21.0 22.9 21.7 5

25–44 years .......................... 22.3 22.7 22.1 22.5 23.5 5

45–64 years .......................... 12.3 13.3 13.3 15.8 15.7 @28

65 years and over ...................... 8.8 12.8 11.3 12.4 19.0 @116

Other race ............................ 8.3 7.2 7.5 7.2 8.8 5

Hospital characteristics

Geographic region:

Northeast ............................. 14.8 16.0 14.3 14.0 13.9 –6

Midwest .............................. 17.5 17.1 15.8 14.5 14.7 –16

South ............................... 13.4 13.9 12.8 12.9 14.4 7

West ................................ 13.4 12.5 12.4 12.8 11.9 –12

Hospital location:

MSA3 ............................... 14.9 14.7 13.4 12.9 13.0 @–13

Non-MSA3 ............................ 13.9 15.1 15.2 15.6 17.1 23
Revised Series 13, No. 150 [ Page 21

Table 3. Annual visit rates for emergency department utilization for injury conditions by selected patient and hospital characteristics:

United States, 1992–99—Con.

Percent

Selected patient and change

hospital characteristics 1992 1993–94 1995–96 1997–98 1999 since 1992

Standard error of rates

All injury visits .......................... 0.57 0.53 0.47 0.42 0.61 . . .

Patient characteristics

Age:

Under 15 years ......................... 0.84 1.03 0.70 0.49 0.64 . . .

15–24 years ........................... 0.79 0.83 0.57 0.35 0.57 . . .

25–44 years ........................... 0.58 0.86 0.51 0.34 0.55 . . .

45–64 years ........................... 0.54 0.79 0.51 0.37 0.50 . . .

65 years and over ........................ 0.79 1.09 0.77 0.51 0.81 . . .

Sex and age:

Female .............................. 0.51 0.48 0.42 0.36 0.60 . . .

Under 15 years ........................ 0.73 0.71 0.54 0.52 0.83 . . .

15–24 years .......................... 1.01 0.76 0.81 0.73 1.12 . . .

25–44 years .......................... 0.71 0.54 0.48 0.46 0.75 . . .

45–64 years .......................... 0.49 0.44 0.41 0.40 0.64 . . .

65 years and over ...................... 1.28 1.25 1.29 1.14 1.80 . . .

Male ................................ 0.68 0.62 0.53 0.51 0.69 . . .

Under 15 years ........................ 1.05 0.94 0.75 0.73 0.91 . . .

15–24 years .......................... 1.33 1.06 1.12 1.06 1.34 . . .

25–44 years .......................... 0.86 0.73 0.65 0.64 0.99 . . .

45–64 years .......................... 0.68 0.41 0.42 0.50 0.59 . . .

65 years and over ...................... 1.30 0.95 1.08 0.92 1.79 . . .

Race and age:

White ............................... 0.64 0.58 0.53 0.47 0.67 . . .

Under 15 years ........................ 0.92 0.84 0.69 0.62 0.85 . . .

15–24 years .......................... 1.19 0.96 1.04 0.96 1.21 . . .

25–44 years .......................... 0.72 0.62 0.57 0.56 0.82 . . .

45–64 years .......................... 0.54 0.38 0.39 0.40 0.55 . . .

65 years and over ...................... 0.68 0.62 0.61 0.54 0.86 . . .

Black ................................ 1.26 1.10 0.82 0.89 1.15 . . .

Under 15 years ........................ 1.73 1.50 1.04 0.95 1.77 . . .

15–24 years .......................... 1.93 1.68 1.29 1.44 1.78 . . .

25–44 years .......................... 2.36 1.44 1.35 1.36 1.63 . . .

45–64 years .......................... 1.46 0.99 0.89 1.24 1.25 . . .

65 years and over ...................... 1.37 1.41 1.37 1.50 2.95 . . .

Other race ............................ 1.60 1.19 1.34 1.04 1.32 . . .

Hospital characteristics

Geographic region:

Northeast ............................. 1.05 1.23 0.82 0.84 1.30 . . .

Midwest .............................. 1.27 1.23 0.99 0.90 1.31 . . .

South ............................... 0.97 0.83 0.80 0.68 1.10 . . .

West ................................ 1.39 1.01 0.95 1.03 1.36 . . .

Hospital location: . . .

MSA3 ............................... 0.68 0.64 0.51 0.48 0.67 . . .

Non-MSA3 ............................ 1.37 1.49 1.59 1.24 1.66 . . .

@ Trend is significant (p<.01).

. . . Category not applicable.

1Based on U.S. Bureau of the Census monthly postcensal estimates of the civilian noninstitutionalized population of the United States as of July 1 of each year. Figures are consistent with the

downloadable series, ‘‘U.S. Population Estimates by Age, Sex, Race, and Hispanic Origin: 1980 to 1999’’ available at the Census Internet site: http://ftp.census.gov/population/www/estimates/

nat_90s_4.html. Figures have been adjusted for net underenumeration using the 1990 National Population Adjustment Matrix.

2Regional estimates were provided by the Division of Health Interview Statistics (DHIS), National Center for Health Statistics, and are also based on U.S. census estimates of the civilian

noninstitutionalized population as of July 1 each year. DHIS estimates differ slightly from monthly postcensal estimates because of differences in the adjustment process.

3MSA is metropolitan statistical area.
Page 22 [ Series 13, No. 150 Revised

Table 4. Mean age and percent distribution of emergency department visits with corresponding standard errors by selected patient and visit

characteristics: United States, 1992–99

Percent

Selected patient and change

visit characteristics 1992 1993–94 1995–96 1997–98 1999 since 1992

Mean age in years

Patient characteristics

Mean age ............................. 33.0 32.8 34.1 35.3 35.7 @8

Percent distribution of emergency department visits

All visits .............................. 100.0 100.0 100.0 100.0 100.0 . . .

Age:

Under 15 years ......................... 25.1 25.3 23.3 22.0 21.3 @–15

15–24 years ........................... 16.5 16.7 16.1 15.6 15.1 @–8

25–44 years ........................... 30.3 30.2 31.1 30.5 31.0 2

45–64 years ........................... 13.9 13.9 14.8 16.4 17.4 @25

65 years and over ........................ 14.1 14.0 14.7 15.5 15.2 @8

75 years and over ........................ 7.7 7.9 8.3 9.1 9.0 @17

Sex:

Female .............................. 51.9 52.2 52.4 52.8 52.8 2

Male ................................ 48.1 47.8 47.6 47.2 47.2 –2

Race:

White ............................... 78.5 77.6 76.7 76.2 76.5 –3

Black ................................ 19.1 20.1 20.8 21.5 20.6 8

Other ................................ 2.4 2.4 2.5 2.3 2.9 20

Visit characteristics

Expected source of payment:

Self pay .............................. 13.4 12.8 16.8 15.6 16.1 @20

Private HMO insurance1 .................... 6.9 7.7 10.0 13.7 15.0 @117

Other private insurance .................... 31.1 30.9 24.8 25.1 25.3 @–19

Medicaid ............................. 22.7 24.0 22.4 17.9 17.4 @–23

Medicare ............................. 13.2 13.0 13.1 15.0 15.0 @14

Other ................................ 12.7 11.6 12.9 12.8 11.1 –13

Type of condition:

Illness ............................... 58.9 58.6 61.4 63.0 63.4 @8

Injury ................................ 41.1 41.5 38.6 37.0 36.6 @–11

Standard error of mean

Patient characteristics

Mean age ............................. 0.56 0.32 0.30 0.34 0.44 . . .

Standard error of percent

All visits .............................. . . . . . . . . . . . . . . . . . .

Age:

Under 15 years ......................... 1.27 0.62 0.58 0.63 0.84 . . .

15–24 years ........................... 0.40 0.23 0.29 0.32 0.41 . . .

25–44 years ........................... 0.69 0.39 0.39 0.39 0.53 . . .

45–64 years ........................... 0.41 0.20 0.23 0.28 0.40 . . .

65 years and over ........................ 0.44 0.37 0.37 0.38 0.46 . . .

75 years and over ........................ 0.30 0.25 0.25 0.27 0.30 . . .

Sex:

Female .............................. 0.43 0.35 0.33 0.30 0.48 . . .

Male ................................ 0.43 0.35 0.33 0.30 0.48 . . .

Race:

White ............................... 1.30 1.01 1.07 0.97 1.15 . . .

Black ................................ 1.23 0.90 0.95 0.91 1.08 . . .

Other ................................ 0.46 0.44 0.44 0.30 0.39 . . .
Revised Series 13, No. 150 [ Page 23

Table 4. Mean age and percent distribution of emergency department visits with corresponding standard errors by selected patient and visit

characteristics: United States, 1992–99—Con.

Percent

Selected patient and change

visit characteristics 1992 1993–94 1995–96 1997–98 1999 since 1992

Standard error of percent

Visit characteristics

Expected source of payment:

Self pay .............................. 0.72 0.52 0.42 0.49 0.64 . . .

Private HMO insurance1 .................... 0.84 0.49 0.57 0.66 0.84 . . .

Other private insurance .................... 1.12 0.69 0.61 0.66 0.81 . . .

Medicaid ............................. 1.03 0.67 0.69 0.51 0.67 . . .

Medicare ............................. 0.49 0.38 0.34 0.40 0.51 . . .

Other ................................ 0.83 0.67 0.61 0.75 0.75 . . .

Type of condition:

Illness ............................... 0.72 0.56 0.54 0.43 0.57 . . .

Injury ................................ 0.72 0.56 0.54 0.43 0.57 . . .

@ Trend is significant (p<.01).

. . .Category not applicable.

1HMO is health maintenance organization.
Page 24 [ Series 13, No. 150 Revised

Table 5. Annual rates of emergency department visits with correspondng standard errors by selected illness and injury conditions:

United States, 1992–99

Percent

change

Selected condition 1992 1993–94 1995–96 1997–98 1999 since 1992

Number of visits per 1,000 persons per year1

Illness condition

Infectious and parasitic diseases .................. 12.4 12.8 11.8 11.6 10.6 –15

Endocrine and metabolic disorders ................ 4.3 4.0 4.5 4.9 6.5 @51

Diabetes ............................... 1.1 1.1 1.3 1.3 2.2 101

Mental disorders ............................ 9.5 9.6 10.2 11.7 10.7 13

Psychoses, excluding major depression ............ 1.6 1.8 2.1 2.5 2.4 @46

Drug dependence and nondependent drug abuse ...... 1.5 1.3 2.2 2.5 2.7 @84

Nervous system and sense organ diseases ........... 24.0 23.3 20.7 20.7 21.6 –10

Otitis media ............................. 12.9 12.7 10.9 9.8 9.7 @–24

Migraine ............................... 3.0 3.1 2.7 3.3 3.2 9

Circulatory system diseases .................... 15.4 14.1 15.8 16.2 16.2 5

Ischemic heart disease ...................... 4.6 3.6 3.6 3.9 3.5 –25

Non-ischemic heart disease ................... 5.5 4.7 5.8 6.0 5.6 2

Hypertension ............................ 1.4 1.8 1.9 1.7 2.2 56

Cerebrovascular disease ..................... 2.1 2.4 2.7 2.5 3.2 @53

Respiratory system diseases .................... 43.4 46.5 46.2 45.7 47.8 10

Acute URI2

, excluding pharyngitis ................ 14.1 15.0 14.3 14.3 14.0 –1

Acute pharyngitis .......................... 5.0 6.3 6.3 5.4 5.9 17

Asthma ................................ 5.8 6.4 7.2 7.4 7.4 @26

Pneumonia .............................. 4.9 4.8 4.7 4.7 5.5 12

Digestive system diseases ..................... 21.8 20.6 20.3 21.2 21.9 1

Noninfectious enteritis and colitis ................ 7.3 6.7 6.0 5.3 6.1 @–17

Genitourinary system diseases ................... 15.2 15.4 15.1 15.1 16.1 6

Urinary tract infection ....................... 4.7 5.3 5.5 4.7 5.5 17

Skin and subcutaneous tissue diseases ............. 10.6 9.9 9.3 9.7 10.4 –2

Musculoskeletal system & connective tissue diseases 15.2 14.4 14.7 17.7 20.5 @35

Arthropathies ............................ 3.4 3.3 3.1 3.7 4.5 32

Spinal disorders (dorsopathies) ................. 5.7 5.4 5.7 7.6 8.6 @51

Ill-defined symptoms ......................... 41.7 43.1 46.6 52.7 60.3 @45

Chest pain .............................. 8.4 8.8 9.9 10.8 12.6 @50

Abdominal pain ........................... 9.1 8.8 10.0 11.3 12.6 @39

Headache .............................. 3.7 3.7 3.6 4.5 4.6 25

Other ill-defined symptoms .................... 5.1 7.0 6.7 8.3 9.1 @79

Supplementary classification .................... 11.9 12.9 12.3 10.9 10.1 @–15

Injury condition

External cause:

Unintentional .............................. 107.8 130.2 111.6 105.6 110.0 2

Falls .................................. 30.5 31.2 28.2 26.3 27.7 @–9

MVTC3 ................................ 15.7 14.9 16.2 15.9 15.0 –5

Struck-by/against .......................... 14.5 14.7 13.2 17.8 15.6 @8

Cut/pierce .............................. 12.2 11.3 10.8 11.1 11.6 –4

Overexertion ............................. 6.3 3.3 5.8 5.3 6.7 6

Natural/environmental ....................... 5.6 6.0 5.3 4.6 6.2 12

Intentional ................................ 7.0 6.5 9.3 8.1 7.4 5

Self-inflicted ............................. 0.6 0.9 1.0 1.6 1.6 @147

Assault ................................ 6.2 5.6 8.1 6.2 5.7 –8

Adverse effects ............................ 3.1 2.1 4.5 4.4 5.2 @67

Nature of injury:

Open wounds ............................. 33.0 30.5 29.6 27.9 26.9 @–19

Fractures ................................ 15.4 14.9 14.3 13.6 13.5 –12

Sprains and strains .......................... 22.0 22.4 22.1 22.2 23.2 5

Superficial ................................ 24.6 25.6 24.2 23.0 22.3 –9

Intracranial ............................... 3.1 3.2 3.3 2.1 1.0 @–67

Burns .................................. 2.7 2.4 2.5 2.5 2.1 –22

Poisoning ................................ 3.9 4.1 3.5 3.0 3.5 –11

Medical complications ........................ 3.0 3.0 3.1 4.9 5.8 @92

Illness condition Standard error of rates

Infectious and parasitic diseases .................. 0.85 0.68 0.61 0.62 0.71 . . .

Endocrine and metabolic disorders ................ 0.33 0.27 0.29 0.27 0.51 . . .

Diabetes ............................... 0.16 0.14 0.14 0.11 0.34 . . .
Revised Series 13, No. 150 [ Page 25

Table 5. Annual rates of emergency department visits with correspondng standard errors by selected illness and injury conditions:

United States, 1992–99—Con.

Percent

change

Selected condition 1992 1993–94 1995–96 1997–98 1999 since 1992

Illness condition—Continued Standard error of rates

Mental disorders ............................ 0.94 0.51 0.51 0.64 0.79 . . .

Psychoses, excluding major depression ............ 0.29 0.18 0.23 0.26 0.28 . . .

Drug dependence and nondependent drug abuse ...... 0.19 0.12 0.19 0.22 0.29 . . .

Nervous system and sense organ diseases ........... 1.43 1.16 0.88 0.95 1.43 . . .

Otitis media ............................. 1.17 0.75 0.57 0.65 0.93 . . .

Migraine ............................... 0.28 0.25 0.19 0.25 0.36 . . .

Circulatory system diseases .................... 0.79 0.68 0.78 0.68 1.00 . . .

Ischemic heart disease ...................... 0.37 0.26 0.25 0.24 0.37 . . .

Non-ischemic heart disease ................... 0.42 0.26 0.39 0.32 0.51 . . .

Hypertension ............................ 0.18 0.21 0.16 0.17 0.31 . . .

Cerebrovascular disease ..................... 0.19 0.19 0.21 0.20 0.32 . . .

Respiratory system diseases .................... 2.33 2.26 1.71 1.89 2.82 . . .

Acute URI2

, excluding pharyngitis ................ 1.12 0.88 0.61 0.76 1.02 . . .

Acute pharyngitis .......................... 0.40 0.40 0.42 0.34 0.73 . . .

Asthma ................................ 0.45 0.40 0.40 0.42 0.48 . . .

Pneumonia .............................. 0.43 0.36 0.30 0.32 0.54 . . .

Digestive system diseases ..................... 1.14 0.89 0.79 0.79 1.35 . . .

Noninfectious enteritis and colitis ................ 0.63 0.41 0.34 0.32 0.59 . . .

Genitourinary system diseases ................... 0.88 0.71 0.68 0.73 0.91 . . .

Urinary tract infection ....................... 0.35 0.29 0.32 0.30 0.40 . . .

Skin and subcutaneous tissue diseases ............. 0.78 0.58 0.54 0.53 0.81 . . .

Musculoskeletal system & connective

tissue diseases ............................ 0.79 0.72 0.60 0.79 1.32 . . .

Arthropathies ............................ 0.29 0.24 0.23 0.28 0.44 . . .

Spinal disorders (dorsopathies) ................. 0.45 0.33 0.30 0.48 0.66 . . .

Ill-defined symptoms ......................... 2.00 1.83 1.91 2.03 3.27 . . .

Chest pain .............................. 0.54 0.45 0.56 0.57 0.79 . . .

Abdominal pain ........................... 0.64 0.45 0.47 0.55 0.84 . . .

Headache .............................. 0.33 0.30 0.22 0.39 0.46 . . .

Other ill-defined symptoms .................... 0.36 0.41 0.41 0.40 0.67 . . .

Supplementary classification .................... 0.73 0.68 0.77 0.58 0.71 . . .

Injury Condition

External cause:

Unintentional .............................. 4.41 4.68 3.81 3.42 4.90 . . .

Falls .................................. 1.39 1.20 1.16 1.02 1.51 . . .

MVTC3 ................................ 0.80 0.67 0.62 0.69 0.90 . . .

Struck-by/against .......................... 0.80 0.71 0.65 0.70 1.06 . . .

Cut/pierce .............................. 0.69 0.61 0.52 0.52 0.80 . . .

Overexertion ............................. 0.48 0.39 0.42 0.32 0.49 . . .

Natural/environmental ....................... 0.45 0.44 0.32 0.28 0.55 . . .

Intentional ................................ 0.63 0.35 0.45 0.40 0.55 . . .

Self-inflicted ............................. 0.16 0.10 0.11 0.15 0.26 . . .

Assault ................................ 0.60 0.31 0.42 0.33 0.44 . . .

Adverse effects ............................ 0.33 0.18 0.30 0.27 0.43 . . .

Nature of injury:

Open wounds ............................. 1.66 1.27 1.01 0.99 1.49 . . .

Fractures ................................ 0.82 0.70 0.68 0.54 0.79 . . .

Sprains and strains .......................... 1.10 0.98 0.94 0.98 1.30 . . .

Superficial ................................ 1.22 1.08 1.03 0.83 1.12 . . .

Intracranial ............................... 0.31 0.23 0.22 0.18 0.17 . . .

Burns .................................. 0.24 0.18 0.20 0.21 0.28 . . .

Poisoning ................................ 0.79 0.41 0.28 0.22 0.38 . . .

Medical complications ........................ 0.30 0.28 0.24 0.34 0.49 . . .

@ Trend is significant (p<.01).

. . . Category not applicable.

1Based on U.S. Bureau of the Census monthly postcensal estimates of the civilian noninstitutionalized population of the United States as of July 1 of each year. Figures are consistent with the

downloadable series, ‘‘U.S. Population Estimates by Age, Sex, Race, and Hispanic Origin: 1980 to 1999’’ available at the Census Internet site: http://ftp.census.gov/population/www/estimates/

nat_90s_4.html. Figures have been adjusted for net underenumeration using the 1990 National Population Adjustment Matrix.

2URI is upper respiratory infection.

3MVTC is motor vehicle traffic crash.
Page 26 [ Series 13, No. 150 Revised

Table 6. Annual rates of emergency department visits with corresponding standard errors by selected services ordered or provided:

United States, 1992–99

Percent

change

Selected service 1992 1993–94 1995–96 1997–98 1999 since 1992

Number per 100 visits per year

Drug mentions

All ages: .............................. 130.8 150.0 152.5 149.4 157.1 @20

Under 15 years ......................... 113.0 126.0 121.6 121.8 120.5 @7

15–24 years ........................... 113.8 130.5 126.9 126.2 131.9 @16

25–44 years ........................... 132.9 154.0 155.5 149.4 160.5 @21

45–64 years ........................... 158.1 176.1 182.5 177.9 186.5 @18

65 years and over ........................ 150.8 182.1 193.1 181.9 192.4 @28

Number of medications mentioned

0 .................................. 30.9 25.6 27.5 28.6 27.5 –11

1 .................................. 32.6 32.5 30.9 30.3 29.0 @–11

2 .................................. 21.0 22.1 21.3 21.2 21.6 3

3 .................................. 9.0 10.4 10.3 10.5 11.2 @25

4 .................................. 3.6 4.6 4.8 4.6 5.2 @44

5 or more ............................. 3.0 4.7 5.3 4.9 5.6 @88

Drug visits by therapeutic drug class

Antimicrobial agents ...................... 19.6 23.0 21.8 20.4 20.5 5

Cardiovascular-renal drugs .................. 5.7 6.8 7.5 7.3 7.4 @30

Drugs used for pain relief ................... 32.5 35.2 36.2 37.3 38.1 @17

Respiratory drugs ........................ 12.5 14.0 14.5 13.4 10.5 @–16

Central nervous system drugs ................ 6.1 6.5 6.5 6.9 8.0 @32

Hormones/hormonal agents .................. 3.7 5.0 6.1 6.1 6.8 @87

Gastrointestinal agents ..................... 4.8 5.2 5.7 5.5 5.8 @21

Metabolic/nutrient agents ................... 2.3 2.5 4.0 4.4 4.4 @88

Immunologics .......................... 4.0 4.2 3.9 3.3 3.4 @–16

Hematologic agents ....................... 1.3 1.6 1.9 2.1 2.2 @75

Diagnostic services

Blood pressure .......................... 73.7 73.6 73.6 72.7 74.4 1

EKG1 ............................... 13.2 12.0 13.5 14.7 14.8 @12

Mental status examination ................... 5.9 . . . 13.4 13.5 13.0 @121

Urinalysis ............................. 15.2 15.9 15.1 15.7 16.2 6

Any imaging ........................... 38.7 38.0 38.7 38.7 39.6 2

CAT scan/MRI2,3 ....................... 2.4 . . . 3.2 4.0 4.9 @103

Extremity x ray ........................ 15.1 14.0 11.9 11.2 10.7 @–29

Chest x ray .......................... 16.8 16.2 16.2 16.6 16.7 –1

None ................................ 12.1 13.8 13.1 12.7 11.0 –9

Therapeutic procedures

Intravenous fluids ........................ 14.4 14.0 15.9 16.7 18.3 @27

Wound care ........................... 12.9 12.6 12.3 12.1 12.2 –5

Orthopedic care ......................... 7.9 9.0 8.2 7.5 8.1 3

Eye, ear, nose, and throat care ................ 2.8 3.1 3.1 3.0 3.1 13

Bladder catheter ......................... 2.6 2.4 2.1 2.1 1.9 @–25

Nasogastric tube/gastric lavage ............... 1.0 0.8 0.7 0.6 0.5 @–50

Endotracheal intubation .................... 0.5 0.4 0.5 0.4 0.2 @–47

CPR4 ............................... 0.3 0.3 0.4 0.3 0.2 –20

None ................................ 57.7 57.7 57.9 58.4 57.5 0

Standard error of rates

Drug mentions

All ages: .............................. 2.57 2.20 2.89 2.81 4.15 . . .

Under 15 years ......................... 2.73 2.63 2.36 2.81 3.75 . . .

15–24 years ........................... 3.07 1.97 2.67 2.55 3.76 . . .

25–44 years ........................... 2.64 2.23 2.92 3.02 4.27 . . .

45–64 years ........................... 4.49 3.91 4.99 4.26 6.40 . . .

65 years and over ........................ 5.81 4.78 6.26 5.70 8.97 . . .
Revised Series 13, No. 150 [ Page 27

Table 6. Annual rates of emergency department visits with corresponding standard errors by selected services ordered or provided:

United States, 1992–99—Con.

Percent

change

Selected service 1992 1993–94 1995–96 1997–98 1999 since 1992

Standard error of rates

Number of medications mentioned

0 .................................. 0.78 0.61 0.74 0.82 1.13 . . .

1 .................................. 0.51 0.42 0.47 0.42 0.62 . . .

2 .................................. 0.44 0.33 0.32 0.38 0.50 . . .

3 .................................. 0.31 0.24 0.25 0.31 0.43 . . .

4 .................................. 0.20 0.18 0.19 0.19 0.28 . . .

5 or more ............................. 0.25 0.25 0.32 0.28 0.48 . . .

Drug visits by therapeutic drug class

Antimicrobial agents ...................... 0.54 0.45 0.44 0.53 0.68 . . .

Cardiovascular-renal drugs .................. 0.28 0.27 0.29 0.61 0.41 . . .

Drugs used for pain relief ................... 0.71 0.56 0.65 0.56 0.83 . . .

Respiratory drugs ........................ 0.46 0.36 0.36 0.38 0.39 . . .

Central nervous system drugs ................ 0.23 0.22 0.22 0.22 0.36 . . .

Hormones/hormonal agents .................. 0.21 0.21 0.21 0.26 0.36 . . .

Gastrointestinal agents ..................... 0.21 0.16 0.20 0.17 0.27 . . .

Metabolic/nutrient agents ................... 0.17 0.13 0.19 0.23 0.30 . . .

Immunologics .......................... 0.08 0.15 0.16 0.13 0.15 . . .

Hematologic agents ....................... 0.09 0.09 0.11 0.10 0.18 . . .

Diagnostic services

Blood pressure .......................... 1.31 1.21 0.96 1.36 1.76 . . .

EKG1 ............................... 0.44 0.31 0.32 0.39 0.54 . . .

Mental status examination ................... 0.90 . . . 1.02 1.03 1.61 . . .

Urinalysis ............................. 0.44 0.32 0.37 0.43 0.43 . . .

Any imaging ........................... 0.65 0.55 0.59 0.61 0.76 . . .

CAT scan/MRI2,3 ....................... 0.18 . . . 0.14 0.16 0.23 . . .

Extremity x ray ........................ 0.41 0.27 0.30 0.29 0.36 . . .

Chest x ray .......................... 0.41 0.36 0.41 0.41 0.53 . . .

None ................................ 0.70 0.69 0.67 0.76 0.83 . . .

Therapeutic procedures

Intravenous fluids ........................ 0.48 0.44 0.40 0.48 0.68 . . .

Wound care ........................... 0.40 0.32 0.34 0.32 0.40 . . .

Orthopedic care ......................... 0.30 0.29 0.30 0.28 0.34 . . .

Eye, ear, nose, and throat care ................ 0.23 0.17 0.18 0.15 0.42 . . .

Bladder catheter ......................... 0.15 0.11 0.12 0.12 0.14 . . .

Nasogastric tube/gastric lavage ............... 0.08 0.05 0.06 0.05 0.07 . . .

Endotracheal intubation .................... 0.05 0.04 0.05 0.04 0.04 . . .

CPR4 ............................... 0.04 0.03 0.04 0.03 0.06 . . .

None ................................ 0.80 0.85 0.68 0.66 0.94 . . .

@ Trend is significant (p<.01).

. . . Category not applicable or data item not on the form during that period.

1EKG is electrocardiogram.

2CAT is computerized axial tomography.

3MRI is magnetic resonance imaging.

4CPR is cardiopulmonary resuscitation.
Page 28 [ Series 13, No. 150 Revised

Table 7. Annual percent of emergency department visits with corresponding standard errors by selected providers seen and disposition of

visit: United States, 1992–99

Percent

change

Selected service 1992 1993–94 1995–96 1997–98 1999 since 1992

Percent of visits

Providers seen

Staff physician .......................... 82.5 84.4 81.8 86.5 88.4 @7

Resident/intern .......................... 13.7 12.6 12.7 9.8 7.1 @–49

Other physician ......................... 11.7 9.8 12.7 8.1 8.5 –27

No physician seen ....................... 3.6 4.0 3.9 5.9 6.0 @68

Midlevel provider ........................ 3.9 3.5 4.6 5.2 6.1 @56

Registered nurse ........................ 83.1 83.5 85.0 88.1 87.7 @5

Licensed practical nurse .................... 6.5 6.1 4.7 5.2 5.5 –15

Disposition

Admitted to hospital ....................... 13.5 12.7 12.6 13.2 12.9 –5

Transferred to other facility .................. 1.2 1.7 1.8 1.8 1.8 @43

DOA/died in ED1,2 ....................... 0.3 0.3 0.3 0.3 0.3 –19

Referred to other physician/clinic ............... 37.0 36.0 40.9 44.7 47.3 @28

No followup planned ...................... 6.0 7.8 8.2 8.7 9.0 @51

Standard error of percent

Providers seen

Staff physician .......................... 1.54 1.18 1.57 0.99 1.30 . . .

Resident/intern .......................... 1.67 1.20 1.09 0.83 0.85 . . .

Other physician ......................... 1.28 0.92 1.24 0.93 0.11 . . .

No physician seen ....................... 0.41 0.44 0.35 0.63 0.66 . . .

Midlevel provider ........................ 0.60 0.54 0.50 0.74 0.86 . . .

Registered nurse ........................ 1.43 1.41 1.34 1.27 1.53 . . .

Licensed practical nurse .................... 1.13 0.75 0.55 0.69 0.92 . . .

Disposition

Admitted to hospital ....................... 0.46 0.36 0.40 0.42 0.50 . . .

Transferred to other facility .................. 0.10 0.10 0.09 0.10 0.16 . . .

DOA/died in ED1,2 ....................... 0.04 0.03 0.04 0.04 0.05 . . .

Referred to other physician/clinic ............... 1.45 1.08 1.04 1.33 1.55 . . .

No followup planned ...................... 0.56 0.72 0.71 0.57 0.72 . . .

@Trend is significant (p<.01).

Category not applicable.

1DOA is dead on arrival.

2ED is emergency department.
Revised Series 13, No. 150 [ Page 29

Appendix I 

Technical Notes

Data Collection

The emergency encounter data for 

the NHAMCS are collected annually 

from about 486 responding hospitals 

with EDs. ED participation rates varied 

slightly between 1992 and 1999, 

between 94–97%. The Census Bureau, 

acting as the data collection agent for 

the survey, provided training to field 

representatives (FRs) throughout the 

nation. FRs contacted the hospitals for 

induction into the survey after an 

advance letter was mailed from NCHS 

notifying the hospitals of selection for 

the survey. In most cases, hospital staff 

completed the information requested on 

the Patient Record forms. However, in 

about one-third of the hospitals, FRs 

abstracted the data from medical records 

or computer printouts. No personally 

identifying information such as patient 

name or address is collected. 

Confidentiality of the data collected in 

the survey is protected under the 

Privacy Act, Public Health Service Act, 

and Title 42 of the United States Code, 

Section 242m (d). 

Estimation

Statistics from the NHAMCS are 

derived by multistage estimation 

procedures that produce essentially 

unbiased estimates. The estimation 

procedure has three basic components: 

a) inflation by reciprocals of the 

sampling selection probabilities; 

b) adjustment for nonresponse; and 

c) a population weighting ratio 

adjustment. The full NHAMCS hospital 

sample is partitioned into 16 panels that 

are rotated into the sample over 16 

periods of 4 weeks each so that only 13 

panels are used in any one year. The 

number of patient records collected in 

the time period studied are 1992: 

36,271; 1993–94: 55,664; 1995–96: 

43,788; 1997–98: 46,387, and 1999: 

21,103. 

Sampling Errors

The standard error is primarily a 

measure of the sampling variability that 

occurs by chance when only a sample, 

rather than an entire universe, is 

surveyed. The standard error also 

reflects part of the measurement error, 

but does not measure any systematic 

biases in the data. The chances are 95 in 

100 that an estimate from the sample 

differs from the value that would be 

obtained from a complete census by less 

than twice the standard error. 

The standard errors used in tests of 

significance for this report were 

estimated using SUDAAN software. 

SUDAAN computes standard errors by 

using a first-order Taylor approximation 

of the deviation of estimates from their 

expected values. A description of the 

software and the approach it uses has 

been published (12). The relative 

standard error (RSE) of an estimate is 

obtained by dividing the standard error 

by the estimate itself. The result is then 

expressed as a percent of the estimate. 

Nonsampling Errors

As in any survey, results are subject 

to both sampling and nonsampling 

errors. Nonsampling errors include 

reporting and processing errors as well 

as biases due to nonresponse and 

incomplete response. The magnitude of 

the nonsampling errors cannot be 

computed. However, these errors were 

kept to a minimum by procedures built 

into the operation of the survey. To 

eliminate ambiguities and to encourage 

uniform reporting, attention was given 

to the phrasing of questions, terms, and 

definitions. Also, pretesting of most data 

items and survey procedures was 

performed. Quality control procedures 

and consistency and edit checks reduced 

errors in data coding and processing. 

The error rate (which includes coding 

and keying errors) ranged from 0.0 to 

1.7 over the study period. 

Adjustments for survey

nonresponse—NHAMCS data were 

adjusted to account for nonresponse at 

the hospital level and at the ED level. 

The response rates varied over the years, 

but they are very high (94–97% of 

eligible hospital EDs). The weights of 

visits from hospitals similar to the 

nonrespondent hospitals were inflated to 

account for visits represented by the 

nonrespondent hospitals, where hospitals 

were judged to be similar if they were 

in the same region and ownership 

control group and had the same 

metropolitan statistical area (MSA) 

status (in an MSA versus not in an 

MSA). The weights of visits from 

responding EDs were inflated to account 

for visits to similar nonrespondent EDs 

where EDs were judged to be similar if 

they were in the same region and size. 

Hospitals were judged similar if they 

were in the same region, ownership 

control group, and metropolitan 

statistical area control group. 

Adjustments for item

nonresponse—Weighted item 

nonresponse rates were 5 percent or less 

for most data items included in this 

report. For some items, missing values 

were imputed by randomly assigning a 

value from Patient Record forms with 

similar characteristics. These items 

included patient’s birth year (used to 

determine age), sex, and race. 

Imputations were based on ED volume, 

geographic region, immediacy with 

which patient should be seen, and 

3-digit ICD–9–CM (19) code for 

primary diagnosis. 

Published and Flagged

Estimates

Estimates are not presented unless a 

reasonable assumption regarding their 

probability distributions is possible on 

the basis of the Central Limit Theorem. 

The Central Limit Theorem states that 

given a sufficiently large sample size, 

the sample estimate approximates the 

population estimate and, upon repeated 

sampling, its distribution would be 

approximately normal. 

In this report, estimates are not 

presented if they are based on fewer 

than 30 cases in the sample data; only 

an asterisk (*) appears in the tables. 

Estimates based on 30 cases or more are 

preceded by an asterisk if the relative 

standard error of the estimate exceeds 

30 percent. 
Page 30 [ Series 13, No. 150 Revised

Tests of Significance and Table I. Codes used for defining diagnoses and causes of injury

Rounding Selected condition ICD–9–CM code1

In this report, the determination of 

statistical inference of trend is based on 

the two-tailed weighted least-squares 

Z-test where the weight is based on the 

relative size of the standard error of the 

estimates involved. The critical value of 

2.56 was used to judge statistical 

significance at the .01 level of 

significance. Terms relating to trends 

such as ‘‘increased’’ or ‘‘decreased’’ 

indicate that the linear trend is 

statistically significant. 

In the tables, estimates of visits 

have been rounded to the nearest 

thousand. Consequently, estimates will 

not always add to totals. Rates and 

percents were calculated from original 

unrounded figures and do not 

necessarily agree with percents 

calculated from rounded data. 

Diagnosis and Injury

Groupings

Physicians’ primary diagnoses, 

shown in table 5 of this report, are 

grouped according to a classification 

system developed for use with 

NHAMCS data. This grouping is based 

on the ICD–9–CM, but also reflects the 

frequency of particular diagnoses 

occurring in the NAMCS and NHAMCS 

data. It is meant to provide additional 

detail on the diagnostic content of 

ambulatory care as characterized by the 

surveys. Table I shows the groupings 

used to categorize data in table 5. 

Table 5 also presents data on the 

intent and mechanism producing the 

injuries that resulted in an ED visit. 

Cause of injury is collected for each 

sampled visit in the NHAMCS and is 

coded according to the ICD–9–CM’s 

Supplementary Classification of External 

Causes of Injury and Poisoning. For 

table 5, however, the first-listed cause of 

injury data were regrouped to highlight 

the interaction between intentionality of 

the injury and the mechanism that 

actually produced the injury. Table I 

displays the groupings used in table 5. 

Illness condition

Infectious and parasitic diseases .................. 001–139

Endocrine and metabolic disorders ................ 240–279

Diabetes ............................... 250

Mental disorders ............................ 290–319

Psychoses, excluding major depression ............ 290–296

Drug dependence and nondependent drug abuse ...... 304–305

Nervous system and sense organ diseases ........... 320–389

Otitis media ............................. 381–382

Migraine ............................... 346

Circulatory system diseases .................... 390–459

Ischemic heart disease ...................... 410–414

Nonischemic heart disease .................... 391–392.0, 393–398, 402, 404, 415–416, 420–429

Hypertension ............................ 401

Cerebrovascular disease ..................... 430–438

Respiratory system diseases .................... 460–519

Acute URI, excluding pharyngitis1 ................ 460–461, 463–466

Acute pharyngitis .......................... 462

Asthma ................................ 493

Pneumonia .............................. 480–486

Digestive system diseases ..................... 520–579

Noninfectious enteritis and colitis ................ 555–558

Genitourinary system diseases ................... 580–629

Urinary tract infection ....................... 599.0

Skin and subcutaneous tissue diseases ............. 680–709

Musculoskeletal system & connective tissue diseases ..... 710–739

Arthropathies ............................ 710–716

Spinal disorders (dorsopathies) ................. 720–724

Ill-defined symptoms ......................... 780–799

Chest pain .............................. 786.5

Abdominal pain ........................... 789.0

Headache .............................. 784.0

Other ill-defined symptoms .................... 780.0–780.1, 780.5, 780.7–780.9, 781, 783,

784.1–784.6, 784.8–784.9, 785.4–785.9,

786.1, 786.3–786.4, 786.6–787, 789.1–799.9

Supplementary classification .................... V01–V82

Injury condition

External cause: ............................ E800–E999

Unintentional .............................. E800–E869, E880–E929

Falls .................................. E888.0–E886.9, E888

MVTC2 ................................ E810–E819

Struck-by/against .......................... E916–E917

Cut/pierce .............................. E920

Overexertion ............................. E927

Natural/environmental ....................... E900–E909, E928.0–E928.2

Intentional ................................ E950–E959, E960–E969, E970–E978, E990–E999

Self-inflicted ............................. E950–E959

Assault ................................ E960–E969

Adverse effects ............................ E870–E879, E930–E949

Nature of injury: ............................ 800–999

Open wounds ............................. 870–899

Fractures ................................ 800–829

Sprains and strains .......................... 840–848

Superficial ................................ 910–924

Intracranial ............................... 850–854

Burns .................................. 940–949

Poisoning ................................ 960–989

Medical complications ........................ 996–999

1ICD–9–CM is the International Classification of Diseases, 9th Revision, Clinical Modification (19).

2MVTC is motor vehicle traffic crash.
Revised Series 13, No. 150

[ Page 31

PopulationFigures and Rate

Calculation

The population figures used in 

computing annual visit rates by age, sex, 

and race for this report are shownin 

table II. The figures represent U.S. 

Bureau of the Census estimates of the 

civilian noninstitutionalized population 

as of July 1,1992, through July 1, 1999. 

Figures are based on monthly postcensal 

estimates and are consistent with the 

downloadable series, U.S. Population

Estimates by Age, Sex, Race and

Hispanic Origin: 1980–1999. It is 

available at the U.S. Bureau of 

the Census Internet site: 

http://ftp.census.gov/population/www/ 

estimates/nat_90s_4.html. 

Figures have been adjusted for net 

underenumeration using the 1990 

National Population Adjustment Matrix. 

Regional estimates were obtained from 

the Division of Health Interview 

Statistics (DHIS), NCHS, and are based 

on U.S. Bureau of the Census estimates 

of the civilian noninstitutionalized 

population as of July 1, 1992, through 

July 1, 1999. DHIS estimates may differ 

slightly from monthly postcensal 

estimates because of differences in the 

adjustment process. 
Page 32 [ Series 13, No. 150 Revised

Table II. Annual civilian noninstitutionalized population estimates for the United States, 1992–99

Selected characteristic 1992 1993–94 1995–96 1997–98 1999

Total ................................ 251,448,459 256,957,372 263,164,954 268,069,746 271,749,305

Age

Under 15 years ......................... 56,442,611 58,193,452 59,476,892 59,785,248 60,193,165

15–24 years ........................... 34,384,602 35,260,085 36,277,705 37,083,542 37,945,857

25–44 years ........................... 81,327,380 82,259,538 83,277,174 83,167,253 82,507,114

46–64 years ........................... 48,501,115 50,096,374 52,462,324 55,822,124 58,641,514

65 years and over ........................ 30,791,751 31,147,924 31,670,860 32,211,580 32,461,655

Sex

Female .............................. 129,260,980 131,857,399 134,861,603 137,334,766 139,275,461

Under 15 years ........................ 27,550,869 28,411,627 29,040,427 29,198,529 29,408,836

15–24 years .......................... 17,286,835 17,628,737 18,017,003 18,385,873 18,849,063

25–44 years .......................... 41,328,729 41,751,174 42,282,966 42,284,807 42,029,126

46–64 years .......................... 25,195,150 25,948,877 27,110,617 28,827,579 30,287,263

65 years and over ...................... 17,899,397 18,116,984 18,410,592 18,637,979 18,701,173

Male ................................ 122,187,479 125,099,973 128,303,352 130,734,980 132,473,844

Under 15 years ........................ 28,891,742 29,781,825 30,436,465 30,586,719 30,784,329

15–24 years .......................... 17,097,767 17,631,348 18,260,703 18,697,669 19,096,794

25–44 years .......................... 39,999,651 40,508,364 40,996,209 40,882,446 40,477,988

46–64 years .......................... 23,305,965 24,147,497 25,351,707 26,994,545 28,354,251

65 years and over ...................... 12,892,354 13,030,941 13,260,269 13,573,602 13,760,482

Race

White ............................... 209,464,504 212,915,572 217,575,584 220,842,178 223,263,366

Under 15 years ........................ 44,985,523 46,045,168 46,763,886 46,924,118 47,171,646

15–24 years .......................... 27,479,788 28,013,928 28,893,536 29,495,444 30,154,665

25–44 years .......................... 67,716,634 68,002,017 68,631,785 68,112,901 67,229,552

46–64 years .......................... 41,743,184 43,137,752 44,982,046 47,649,273 49,910,737

65 years and over ...................... 27,539,375 27,850,208 28,304,333 28,660,443 28,796,766

Black ................................ 31,461,180 32,532,632 33,638,928 34,455,861 35,114,071

Under 15 years ........................ 8,954,786 9,350,925 9,594,974 9,602,725 9,647,649

15–24 years .......................... 5,100,047 5,274,339 5,475,175 5,591,796 5,714,083

25–44 years .......................... 9,795,335 10,176,637 10,548,881 10,725,451 10,804,292

46–64 years .......................... 4,989,293 5,132,605 5,421,594 5,852,183 6,215,500

65 years and over ...................... 2,621,722 2,598,128 2,598,305 2,683,708 2,732,547

Other ................................ 10,522,775 11,509,168 11,950,443 12,771,707 13,371,868

Under 15 years ........................ 2,502,302 2,797,359 6,236,064 3,258,406 3,373,870

15–24 years .......................... 1,804,767 1,971,819 1,908,994 1,996,302 2,077,109

25–44 years .......................... 3,816,414 4,080,884 8,193,018 4,328,901 4,473,270

46–64 years .......................... 1,768,638 1,959,517 2,058,684 2,320,669 2,515,277

65 years and over ...................... 630,654 699,590 768,224 867,430 932,342

Geographic region

Northeast ............................. 50,000,327 50,326,711 52,938,232 52,173,508 52,541,088

Midwest .............................. 61,472,387 62,639,234 61,581,369 66,228,955 66,830,045

South ............................... 84,419,002 86,811,641 91,793,259 95,365,391 96,499,838

West ................................ 55,556,743 57,270,786 56,600,508 54,050,321 55,820,082

MSA status1

MSA1 ............................... 196,606,190 201,270,278 210,671,956 212,600,052 215,622,467

Non-MSA1 ............................ 54,842,269 55,687,094 52,241,411 55,218,124 56,068,586

1MSA is metropolitan statistical area.

SOURCE: Based on U.S. Bureau of the Census monthly postcensal estimates of the civilian noninstitutionalized population of the United States as of July 1 of each year. Figures are consistent with

the downloadable series, ‘‘U.S. Population Estimates by Age, Sex, Race, and Hispanic Origin: 1980 to 1999’’ available at the Census Internet site: http://ftp.census.gov/population/www/estimates/

nat_90s_4.html. Figures have been adjusted for net underenumeration using the 1990 National Population Adjustment Matrix.

Regional estimates were provided by the Division of Healh Interview Statistics (DHIS), National Center for Health Statistics, and are also based on U.S. census estimates of the civilian

noninstitutionalized population as of July 1 each year. DHIS estimates differ slighlty from monthly postcensal estimates because of differences in the adjustment process.
Revised Series 13, No. 150 [ Page 33

Appendix II 

Definitions of Terms

Terms Relating to the Survey

Emergency department —An 

emergency department (ED) is a 

hospital facility for the provision of 

unscheduled outpatient services to 

patients whose conditions require 

immediate care and is staffed 24 hours a 

day. If an ED provided emergency 

services in different areas of the 

hospital, then all of these emergency 

service areas are selected with certainty 

into the sample. Off-site EDs that are 

open less than 24 hours are included if 

staffed by the hospital’s ED. 

Geographic region of hospital—The 

four geographic regions that correspond 

to those used by the Bureau of the 

Census: 

NortheastConnecticut, Maine, 

Massachusetts, New 

Hampshire, New Jersey, 

New York, Pennsylvania, 

Rhode Island, and 

Vermont. 

MidwestIllinois, Indiana, Iowa, 

Kansas, Michigan, 

Minnesota, Missouri, 

Nebraska, North Dakota, 

Ohio, South Dakota, and 

Wisconsin. 

SouthAlabama, Arkansas, 

Delaware, District of 

Columbia, Florida, 

Georgia, Kentucky, 

Louisiana, Maryland, 

Mississippi, North 

Carolina, Oklahoma, South 

Carolina, Tennessee, Texas, 

Virginia, and West Virginia. 

WestAlaska, Arizona, 

California, Colorado, 

Hawaii, Idaho, Montana, 

Nevada, New Mexico, 

Oregon, Utah, Washington, 

and Wyoming. 

Hospital—To be in scope for the 

NHAMCS, a hospital must have an 

average length of stay for all patients of 

less than 30 days (short-stay) or 

hospitals whose specialty is general 

(medical or surgical) or children’s 

general, except Federal hospitals, 

hospital units of institutions, and 

hospitals with less than six beds staffed 

for patient use. 

Outpatient department—An 

outpatient department is a hospital 

facility where nonurgent ambulatory 

medical care is provided under the 

supervision of a physician. 

Ownership—Hospitals are 

designated according to the primary 

owner of the hospital based on the SMG 

Hospital Database. 

Voluntary nonprofit: Hospitals that 

are church-related or are a nonprofit 

corporation or have other nonprofit 

ownership. 

Government, non-Federal: Hospitals 

that are operated by State, county, 

city, city-county, or hospital district 

or authority. 

Proprietary: Hospitals that are 

individually or privately owned or 

are partnerships or corporations. 

Patient—A patient is an individual 

seeking personal health services who is 

not currently admitted to any health care 

institution on the premises. Excluded are 

patients who contact and receive advice 

from the emergency physician via 

telephone or patients who come to the 

emergency department only for 

administrative purposes (e.g., to pick up 

insurance forms or to pay a bill). 

Visit—A visit is a direct, personal 

exchange between an ambulatory patient 

seeking care and a physician or other 

hospital staff member working under the 

physician’s supervision for the purpose 

of rendering emergency health services. 

Terms Relating to the Patient

Record Form

Age—The age calculated from date 

of birth was the age at last birthday on 

the date of visit. 

Race—Hospital staff were 

instructed to check the category they 

judged to be the most appropriate for 

each patient based on observation or 

prior knowledge. Starting in 1999, 

hospital staff were asked to record all 

races that apply. For trend purposes, the 

1999 data were recorded to make a 

separate category called ‘‘multiracial,’’ 

but there were too few cases to provide 

a reliable estimate. Other race selections 

were recoded to be consistent with 

previous categories. The following 

definitions were provided to the hospital 

staff from 1992–98: 

+ White—A person having origins in 

any of the original peoples of 

Europe, the Middle East, or North 

Africa. 

+ Black—A person having origins in 

any of the black racial groups of 

Africa. 

+ Asian/Pacific Islander—A person 

having origins in any of the original 

peoples of the Far East, Southeast 

Asia, the Indian subcontinent, or the 

Pacific Islands. 

+ American Indian/Eskimo/Aleut—A 

person having origins in any of the 

original peoples of North, South, or 

Central America and who maintains 

cultural identification through tribal 

affiliation or community attachment. 

Expected source(s) of payment— 

The source(s) that to the best of the 

hospital staff’s knowledge describes how 

charges incurred this visit will be paid: 

+ Patient-paid—Charges billed 

directly to the patient that will not 

be reimbursed by a third party. Does 

not include prepaid plans for which 

copayment is charged. 

+ Medicare—Charges paid in part or 

in full by a Medicare plan, including 

payments made directly to the 

hospital as well as payments to the 

patient. 

+ Medicaid—Charges paid in part or 

in full by a Medicaid plan, including 

payments made directly to the 

hospital as well as payment to the 

patient. 

+ Private/commercial insurance— 

Charges paid in part or in full by a 

private insurance company, 

including payments reimbursed to 

the patient. If charges are covered 

under a Blue Cross/Blue 

Shield-sponsored prepaid plan, the 

physician is requested to check both 

the private/commercial insurance 

and the ‘‘HMO/other prepaid’’ 

category. 
Page 34 [ Series 13, No. 150 Revised

+ HMO/other prepaid—Charges 

included under a health maintenance 

organization (HMO) plan or other 

prepayment plan, including 

independent practice associations 

(IPAs) and preferred provider 

organizations (PPOs). Starting in 

1997, there was a separate item on 

HMO status. 

+ No charge—Visits for which no fee 

is charged (not including visits paid 

for as part of a total care package, 

e.g., post-operative visits included in 

a surgical fee, pregnancy visits for 

which a flat fee was charged, and 

HMO and prepaid systems). 

+ Other and unknown—All other 

sources of payment not in the 

preceding categories (e.g., private 

charitable institutions). Charges paid 

under any other local, State, or 

Federal health care program such as 

worker’s compensation programs 

and CHAMPUS. This category also 

includes a small percent of cases 

where none of the previous source 

of payment categories was checked. 

The expected source of payment 

item varied over the study period. From 

1992–94, the item was a multiple 

selection item allowing the respondent 

to check as many sources that might 

apply. In 1995 and 1996, the item was 

split into two sections allowing multiple 

selection for type of insurance (e.g., 

Medicaid, Medicare, private, worker’s 

compensation), but single selection for 

other sources (e.g., fee-for-service 

insurance, HMO, self-pay, charity). 

From 1997–99, the items were again 

rewritten to make two different items, a 

single selection for source of payment 

and a separate item for HMO status of 

the patient (e.g., Is patient a member of 

an HMO?). Because the payment item 

varied over the years from multiple to 

single selection, an algorithm was used 

to arrive at a primary payer whereby 

Medicaid and Medicare (regardless of 

HMO status) were assigned a higher 

priority than private insurance or 

self-pay when more than one category 

was indicated. The ‘‘Other and unknown 

payer source’’ category had the lowest 

priority. It included worker’s 

compensation, charity, and other 

sources. With private insurance, HMO 

status was assigned a higher priority 

than private insurance without any 

mention of HMO membership. 

Illness-related visit—A visit is 

considered illness-related if it was not 

an injury visit as defined below. 

Injury-related visit—A visit is 

injury-related if ‘‘yes’’ was checked in 

response to ‘‘Is visit related to injury or 

poisoning?’’ if a cause of injury or a 

nature of injury diagnosis was provided, 

or if an injury-related reason for visit 

was reported. After 1992, this definition 

was built into the survey edits. For this 

report, the 1992 data were recoded using 

this definition. 

Physician’s diagnosis—Hospital 

staff were instructed to record the 

physician or other health care provider’s 

best assessment of diagnosis of the 

patient’s most important problem, 

complaint, or symptom. In the event of 

multiple diagnoses, the physician was 

instructed to list them in order of 

decreasing importance. The term 

‘‘primary’’ refers to the first-listed 

diagnosis. The diagnosis represents the 

provider’s best judgment at the time of 

the visit and may be tentative, 

provisional, or definitive. 

Medication—Hospital staff were 

instructed to record all new or continued 

medications ordered, supplied, or 

administered at the visit. This included 

prescription and nonprescription 

preparations, immunizations, and 

desensitizing agents and anesthetics. 

Providers were requested to record the 

same specific medication name (brand 

or generic) that was used on any 

prescription listed in the hospital 

medical record. Also included are 

medications ordered or provided prior to 

the visit that the hospital staff instructed 

or expected the patient to continue 

taking. From 1992 through 1994, up to 

five medications were collected. Starting 

in 1995, up to six medications were 

recorded. For this study, only the first 

five mentions were analyzed. 

Drug mention—A drug mention is 

the health care provider’s entry on the 

Patient Record form of a pharmaceutical 

agent ordered or provided by any route 

of administration for prevention, 

diagnosis, or treatment. Generic as well 

as brand name medications are included 

as are nonprescription and prescription 

drugs. Along with all new drugs, 

hospital staff also record continued 

medications if the patient was 

specifically instructed during the visit to 

continue the medication. 

Disposition this visit—Categories 

varied by survey year, but the consistent 

categories are listed below. The provider 

was instructed to check as many of the 

following categories as apply: 

+ No followup planned—No return 

visit or telephone contact was 

scheduled or planned for the 

patient’s problem. 

+ Referred to other physician/clinic— 

Patient was screened, evaluated, 

stabilized, and then referred to 

another physician or clinic for 

followup. 

+ Admitted to hospital—Patient was 

instructed that further care or 

treatment would be provided as an 

inpatient in the hospital. For this 

report, it includes admission to 

critical and intensive care units in 

the hospital. This is a separate 

disposition item. Starting in 1997, 

survey edits automatically indicated 

hospital admission if the critical care 

unit was so marked. 

+ Transferred to other facility— 

Patient was transferred to another 

facility other than a facility operated 

under the auspices of the hospital 

(e.g., another acute care hospital, 

nursing home, jail, drug or alcohol 

detoxification, or mental institution). 

+ DOA/died in ED—Patient arrived at 

the ED dead on arrival (DOA) or 

died in the ED. 
Vital and Health Statistics

series descriptions

SERIES 1.	 Programs and Collection Procedures—These reports 

describe the data collection programs of the National Center 

for Health Statistics. They include descriptions of the methods 

used to collect and process the data, definitions, and other 

material necessary for understanding the data. 

SERIES 2.	 Data Evaluation and Methods Research—These reports are 

studies of new statistical methods and include analytical 

techniques, objective evaluations of reliability of collected data, 

and contributions to statistical theory. These studies also 

include experimental tests of new survey methods and 

comparisons of U.S. methodology with those of other 

countries. 

SERIES 3.	 Analytical and Epidemiological Studies—These reports 

present analytical or interpretive studies based on vital and 

health statistics. These reports carry the analyses further than 

the expository types of reports in the other series. 

SERIES 4.	 Documents and Committee Reports—These are final 

reports of major committees concerned with vital and health 

statistics and documents such as recommended model vital 

registration laws and revised birth and death certificates. 

SERIES 5.	 International Vital and Health Statistics Reports—These 

reports are analytical or descriptive reports that compare U.S. 

vital and health statistics with those of other countries or 

present other international data of relevance to the health 

statistics system of the United States. 

SERIES 6.	 Cognition and Survey Measurement—These reports are 

from the National Laboratory for Collaborative Research in 

Cognition and Survey Measurement. They use methods of 

cognitive science to design, evaluate, and test survey 

instruments. 

SERIES 10.	 Data From the National Health Interview Survey—These 

reports contain statistics on illness; unintentional injuries; 

disability; use of hospital, medical, and other health services; 

and a wide range of special current health topics covering 

many aspects of health behaviors, health status, and health 

care utilization. They are based on data collected in a 

continuing national household interview survey. 

SERIES 11.	 Data From the National Health Examination Survey, the

National Health and Nutrition Examination Surveys, and

the Hispanic Health and Nutrition Examination Survey— 

Data from direct examination, testing, and measurement on 

representative samples of the civilian noninstitutionalized 

population provide the basis for (1) medically defined total 

prevalence of specific diseases or conditions in the United 

States and the distributions of the population with respect to 

physical, physiological, and psychological characteristics, and 

(2) analyses of trends and relationships among various 

measurements and between survey periods. 

SERIES 12.	 Data From the Institutionalized Population Surveys— 

Discontinued in 1975. Reports from these surveys are 

included in Series 13. 

SERIES 13.	 Data From the National Health Care Survey—These reports 

contain statistics on health resources and the public’s use of 

health care resources including ambulatory, hospital, and longterm care services based on data collected directly from 

health care providers and provider records. 

SERIES 14.	 Data on Health Resources: Manpower and Facilities— 

Discontinued in 1990. Reports on the numbers, geographic 

distribution, and characteristics of health resources are now 

included in Series 13. 

SERIES 15.	 Data From Special Surveys—These reports contain statistics 

on health and health-related topics collected in special 

surveys that are not part of the continuing data systems of the 

National Center for Health Statistics. 

SERIES 16.	 Compilations of Advance Data From Vital and Health

Statistics—Advance Data Reports provide early release of 

information from the National Center for Health Statistics’ 

health and demographic surveys. They are compiled in the 

order in which they are published. Some of these releases 

may be followed by detailed reports in Series 10–13. 

SERIES 20.	 Data on Mortality—These reports contain statistics on 

mortality that are not included in regular, annual, or monthly 

reports. Special analyses by cause of death, age, other 

demographic variables, and geographic and trend analyses 

are included. 

SERIES 21.	 Data on Natality, Marriage, and Divorce—These reports 

contain statistics on natality, marriage, and divorce that are 

not included in regular, annual, or monthly reports. Special 

analyses by health and demographic variables and 

geographic and trend analyses are included. 

SERIES 22.	 Data From the National Mortality and Natality Surveys— 

Discontinued in 1975. Reports from these sample surveys, 

based on vital records, are now published in Series 20 or 21. 

SERIES 23.	 Data From the National Survey of Family Growth—These 

reports contain statistics on factors that affect birth rates, 

including contraception, infertility, cohabitation, marriage, 

divorce, and remarriage; adoption; use of medical care for 

family planning and infertility; and related maternal and infant 

health topics. These statistics are based on national surveys 

of women of childbearing age. 

SERIES 24.	 Compilations of Data on Natality, Mortality, Marriage,

Divorce, and Induced Terminations of Pregnancy— 

These include advance reports of births, deaths, marriages, 

and divorces based on final data from the National Vital 

Statistics System that were published as supplements to the 

Monthly Vital Statistics Report (MVSR). These reports provide 

highlights and summaries of detailed data subsequently 

published in Vital Statistics of the United States. Other 

supplements to the MVSR published here provide selected 

findings based on final data from the National Vital Statistics 

System and may be followed by detailed reports in Series 20 

or 21. 

For answers to questions about this report or for a list of reports published in 

these series, contact: 

Data Dissemination Branch


National Center for Health Statistics


Centers for Disease Control and Prevention


6525 Belcrest Road, Room 1064


Hyattsville, MD 20782-2003


(301) 458–4636


E-mail: nchsquery@cdc.gov


Internet: www.cdc.gov/nchs

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DHHS Publication No. (PHS) 2001-1721, Series 13, No. 150

01-0492 (Revised 11/01)