Vital and Health Statistics


Series 13, Number 149 

Utilization of Ambulatory 

Medical Care by Women: 

United States, 1997–98 

Data From the National Health 

Care Survey 

U.S. DEPARTMENT OF HEALTH AND HUMAN SERVICES


Centers for Disease Control and Prevention


National Center for Health Statistics


Hyattsville, Maryland


July 2001


DHHS Publication No. (PHS) 2001-1720

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 

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 

Division of Epidemiology 

Thomas Hodgson, Ph.D., Acting Director 

Thomas Hodgson, Ph.D., Acting Chief, Population 

Epidemiology Branch 
Contents


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


Highlights................................................................................................ 1


Patient Characteristics .................................................................................... 1


Provider Characteristics................................................................................... 1


Visit Characteristics...................................................................................... 1


Introduction .............................................................................................. 2


Methods ................................................................................................. 3


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


Patient Characteristics .................................................................................... 4


Provider Characteristics................................................................................... 5


Visit Characteristics...................................................................................... 5


Comparison of Ambulatory Care by Women and Men .......................................................... 12


Discussion ............................................................................................... 13


References ............................................................................................... 16


Appendix ............................................................................................... 41


Technical Notes ......................................................................................... 41


Definition of Terms ...................................................................................... 42


Survey Instruments ...................................................................................... 44


Figures 

1. Women’s ambulatory care visits by specialty, place of care, and age ........................................... 4


2. Women’s office-based physician visits by physician’s specialty ................................................ 5


3. Age-adjusted female visit rates by expected source of payment and race ........................................ 6


4. Women’s major reason for visit by age ................................................................... 6


5. Women’s specific reason for visit by age.................................................................. 7


6. Reason for visit by pregnant women ..................................................................... 7


7. Age-adjusted female visit rates for selected diagnostic groups by race .......................................... 8


8. Age-adjusted female visit rates of injury visits by age and race................................................ 8


9. Female visit rates for selected diagnostic and screening services by age......................................... 9


10. Female visit rates where selected therapeutic and preventive services were provided by age ........................ 10


11. Female visit rates by number of drug mentions and age...................................................... 10


12. Percent of drug mentions among female ambulatory care visits for top therapeutic classes.......................... 11


13. Female prescription rates for selected cardiovascular drugs by age and race...................................... 11


14. Female prescription rates for selected diabetes related drugs by age and race .................................... 12


15. Female prescription rates for antidepressants and antianxiety agents by age and race .............................. 12


16. Age-adjusted visit rates of women with nonpregnancy diagnoses and men by age and race ......................... 13


17. Age-adjusted visit rates by place of care for women with nonpregnancy diagnoses and men ........................ 13


18. Age-adjusted visit rates by major reason for visit for women with nonpregnancy diagnoses and men ................. 14


19. Age-adjusted prescription rates by major therapeutic classes for women with nonpregnancy diagnoses and men ........ 14


iii

Detailed Tables 

1. Ambulatory care visits by physician’s specialty and patient’s age and race: United States, average annual 1997–98 ..... 18


2.	 Ambulatory care visits by detailed specialty of care and ambulatory care setting for women 15 years of age and over:


United States, average annual 1997–98 ................................................................... 20


3.	 Ambulatory care visits to office-based physicians and hospital outpatient departments by type of provider seen,


according to age and race for women 15 years of age and over: United States, annual average 1997–98 .............. 21


4.	 Expected source of payment for ambulatory care visits by age and race for women 15 years of age and over:


United States, average annual 1997–98 ................................................................... 22


5.	 Ambulatory care visits to office-based physicians and hospital outpatient departments by major reason for visit, age,


and race for women 15 years of age and over: United States, average annual 1997–98............................. 23


6.	 Ambulatory care visits for the 10 principal reasons for visit most frequently mentioned by age and race for women


15 years of age and over: United States, annual average 1997–98.............................................. 25


7.	 Ambulatory care visits for the 10 diagnosis groups most frequently mentioned by age and race for women 15 years


of age and over: United States, average annual 1997–98 ..................................................... 27


8.	 Injury-related ambulatory care visits by age and race for women 15 years of age and over: United States, average


annual 1997–98 ...................................................................................... 28


9.	 Ambulatory care visits by place of occurrence, whether injury was work related, intent, and mechanism for women


15 years of age and over: United States, average annual 1997–98.............................................. 29


10.	 Visits to office-based physicians and hospital outpatient departments for selected diagnostic and screening services


ordered or provided, by age and race for women 15 years of age and over: United States, average annual 1997–98 ..... 30


11. Visits to office-based physicians and hospital outpatient departments for selected therapeutic and preventive services


ordered or provided, by to age and race for women 15 years of age and over: United States, average annual


1997–98 ............................................................................................ 32


12.	 Ambulatory care visits by number of medications provided or prescribed, by age and race for women 15 years of age


and over: United States, average annual 1997–98 ........................................................... 34


13.	 Drug mentions of the 10 generic substances most frequently used at ambulatory care visits by age and race for women


15 years of age and over: United States, average annual 1997–98.............................................. 36


14.	 Drug mentions of the 10 therapeutic classes of drugs most frequently used at ambulatory care visits by age and race for


women 15 years of age and over: United States, average annual 1997–98 ....................................... 38


15. Use of ambulatory care by women with nonpregnancy diagnoses and men: United States, average annual 1997–98 ..... 40


Appendix Tables 

I.	 Average annual U.S. population estimates used in computing annual visit rates for the National Ambulatory Medical


Care Survey and the National Hospital Ambulatory Medical Care Survey, by age, sex, and race: July 1, 1997, and


July 1, 1998 ........................................................................................ 42


II. Reclassification of physician specialty for use with National Ambulatory Medical Care Survey data .................. 43


iv 
Objectives 

This report presents national 

estimates of the volume and 

characteristics of ambulatory medical 

care provided to women 15 years of 

age and over in the United States. 

Included is information on the 

characteristics of the patients, 

providers, and visits. A section on 

comparative differences in use by sex 

is also included. 

Source of Data 

This report is based on an analysis 

of data from the 1997 and 1998 

National Ambulatory Medical Care 

Survey (NAMCS) and National Hospital 

Ambulatory Medical Care Survey 

(NHAMCS), national probability sample 

surveys of visits to office-based 

physicians (NAMCS) and visits to the 

outpatient departments and emergency 

departments of non-Federal, short-stay 

and general hospitals (NHAMCS) in the 

United States. Sample data are 

weighted to produce annual estimates. 

Results 

Approximately 500 million visits were 

made by women to ambulatory medical 

care providers annually in 1997 and 

1998, representing an age-adjusted 

rate of 4.6 visits per woman per year. 

The rate of ambulatory medical care 

visits increased with age (3.8 per 

woman 15–44 years of age, 4.7 visits 

per woman 45–64 years of age, and 

7.1 visits per woman 65 years of age 

and over). Six out of ten visits to 

office-based physicians and hospital 

outpatient departments had no mention 

of therapeutic or preventive services 

provided. Nonnarcotic analgesics, 

antidepressant, and estrogen/progestin 

were the three most common 

classifications of medications 

mentioned. Compared with visits by 

men, visits by women (with 

nonpregnancy-related diagnoses) were 

more frequent at younger ages and 

more likely to be to primary care 

physicians and outpatient departments. 

Keywords: women’s health c

ambulatory care visits c health care 

utilization 

Utilization of Ambulatory 

Medical Care by Women: 

United States, 1997–98 

by Kate M. Brett, Ph.D., Division of Epidemiology, and Catharine W. 

Burt, Ed.D., Division of Health Care Statistics 

Highlights 

+ Approximately 500 million visits 

were made by women to ambulatory 

medical care providers each year in 

1997 and 1998. This represents an 

age-adjusted annual rate of 4.6 visits 

per woman per year (table 1). 

Patient Characteristics 

+ Among all visits made by women 

15 years of age and older, 

46 percent were made by 

reproductive-aged women (15–44 

years of age). However, women in 

this age group represent 56 percent 

of all women over 15 years of age 

(table 1). 

+ The rate of all ambulatory medical 

care visits increased with age, from 

3.8 per woman 15–44 years of age 

to 4.7 visits per woman 45–64 years 

of age and 7.1 visits per woman 65 

years of age and over (table 1). 

+ Visits by women 15–44 years of age 

were more likely to be to primary 

care physicians and emergency 

departments than visits by older 

women. Senior women were more 

likely to be seen by physicians in 

surgical and nonsurgical specialties 

(table 1). 

+ Compared with white women, black 

women had higher rates of visits for 

hypertension (85 percent higher), 

complications of pregnancy 

(81 percent higher), arthropathies 

(50 percent higher), and diabetes 

(138 percent higher) (figure 7). 

Provider Characteristics 

+ More than four out of five 

ambulatory medical care visits were 

made to office-based physicians. The 

remaining visits were equally split 

between hospital outpatient 

departments and emergency 

departments (table 2). 

+ Almost all women, regardless of age 

or race, saw a physician during 

ambulatory medical care visits 

(95 percent overall). Women also 

saw registered nurses (17 percent of 

visits), licensed practical nurses 

(11 percent of visits), and/or 

medical/nursing assistants 

(23 percent of visits) during 

ambulatory care visits (table 3). 

Visit Characteristics 

+ While the expected source of 

payment for 50 percent of visits was 

private insurance, visits by white 

women were 1.3 times as likely to 

be covered by private insurance as 

NOTE: This report was prepared in the Division of Epidemiology and the Division of Health Care 

Statistics. The assistance and expertise of the following persons, who contributed to this report is gatefully 

acknowledged. Amy B. Bernstein and Irma E. Arispe, Division of Health Care Statisitcs, provided 

comments on the paper. Jaime L. Oliver, Division of Health Care Statistics, and Jennifer A. Higgins, 

Division of Epidemiology, prepared and edited tables. The report was edited by Gail V. Johnson and 

typeset by Annette F. Holman of the Publications Branch, Division of Data Services. 

Page 1 
Page 2 [ Series 13, No. 149 

were visits by black women. 

Conversely, visits by black women 

were three times as likely as white 

women to be covered by Medicaid, 

which overall covered 9 percent of 

visits (table 4). 

+ The most frequently cited reasons 

for office-based and outpatient 

hospital ambulatory care visits were 

chronic conditions (39 percent), 

acute conditions (31 percent), and 

preventive care or other non-illness 

purposes (21 percent) (table 5). 

+ Thirty-one percent of visits for 

women 15–44 years of age were for 

preventive care and other non-illness 

reasons compared with 10 percent of 

visits in the 65 and older age group 

figure 4). 

+ The most frequently cited specific 

reasons for ambulatory visits were 

general medical examination 

(7 percent of total adult female 

visits), routine prenatal examination 

(6 percent), and progress visit 

(4 percent) (table 6). 

+ The most common diagnostic groups 

noted for visits by women were 

normal pregnancy (6 percent), 

essential hypertension (4 percent) 

and arthropathies (3 percent) 

(table 7). 

+ Injury- and poisoning-related visits 

represented 11 percent of all 

ambulatory care visits (table 8). 

Rates of injury-related visits 

increased from 46 visits per 100 

women in the 15–44 age group to 

66 visits per 100 women in the 65 

and over age group—a 43 percent 

increase (figure 8). 

+ The leading causes of injury visits 

by women were falls (17 percent) 

and motor vehicle crashes 

(11 percent) (table 9). 

+ The most common diagnostic or 

screening service ordered or 

performed during ambulatory 

medical care visits was blood 

pressure screening (56 percent of all 

visits), pelvic exam (14 percent), and 

urinanalysis (14 percent) (table 10). 

+ The rate of mammography use 

among women 65 years of age and 

over was 29 percent lower than the 

rate for women 45–64 years of age 

(19.3 versus 27.1 visits per 100 

women) (figure 9). 

+ Of visits by women 15 years of age 

and over to office-based physicians 

and hospital outpatient departments, 

41 percent included one or more 

therapeutic or preventive service. 

Diet (15 percent) and exercise 

(11 percent) counseling were the two 

most common types of services 

reported in this category (table 11). 

+ When analyzed using only the 20 

major therapeutic classes, drugs for 

the cardiovascular-renal system, 

hormones, and central nervous 

system were the top classes of drugs 

used by women 15 years of age and 

over in 1997–98. When the detailed 

classes of drugs are analyzed, 

nonnarcotic analgesics, 

antidepressant, and 

estrogen/progestin were the three 

most common classifications of 

medications mentioned (figure 12). 

+ Visits by senior women were more 

likely to have had medication 

provided or prescribed and to have 

multiple drugs provided or 

prescribed than were visits by 

younger women (figure 11). 

+ Acetaminophen and estrogen were 

the two generic substances most 

frequently used in drugs ordered or 

provided during ambulatory care 

visits by women of all ages, 

occurring in 3.6 percent and 

2.2 percent of drug mentions, 

respectively (table 13). 

+ The rate of ambulatory care use 

among women with nonpregnancy 

related diagnoses was 33 percent 

higher than that for men. This 

difference by sex in the rate of 

ambulatory care use did not differ 

by race, and decreased with age 

from over 50 percent more visits by 

women 15–44 years of age than 

men in this age group to virtually no 

difference in the rate of visits by 

women and men 65 years of age 

and over (figure 16). 

+ The age-adjusted rate of visits by 

women with nonpregnancy related 

diagnoses to primary care physicians 

was 58 percent higher and to 

outpatient departments was 

40 percent higher than the rate of 

visits to these providers by men 

(figure 17). 

+ Utilization rates categorized by 

major reason for visit disclose that 

while the visit rates by women were 

at least somewhat higher for all 

types of care, the rate of visits by 

women for non-illness (for example, 

annual examinations) was 

100 percent higher than among men, 

after controlling for age and 

removing pregnancy-related visits 

(table 15). 

+ There were large differences in the 

rate of drug mentions by sex for 

medications with central nervous 

system mechanisms. The 

age-adjusted rate of antidepressant 

mentions among women was 

95 percent of the rate of all CNS 

medication mentions in visits by 

men. 

Introduction 

I

Improving the health of all 

Americans has long been a major 

goal for this Nation. It has only 

been in the last 20 years, however, that 

it has been generally recognized that the 

health concerns of women are different 

from the health concerns of the 

population as a whole. Recent Federal 

reports have emphasized the need for 

more information on the health of 

women in the United States, the lack of 

commitment to health research specific 

to women, and strategies for improving 

women’s health (1,2). The term 

‘‘women’s health,’’ while originally 

associated with the reproductive health 

of women, has expanded over time to 

include all the factors that affect a 

woman’s health and quality of life 

throughout her lifespan (3). 

One set of factors that has profound 

effects on the health of women is the 

manner in which health care is provided 

and utilized. For example, the use of 

preventive health services should reduce 

future morbidity and mortality. While it 

is widely acknowledged that women 

have greater use of medical care (4), 

this does not mean that the utilization is 

correctly distributed by type and amount 

relative to need. Furthermore, medical 

care utilization information is important 

in debates about the allocation of health 
Series 13, No. 149 [ Page 3 

care resources. Policy regarding health 

and health care must be grounded on 

such information. 

Much of the recent literature on 

women’s health has been based on 

survey research where women are asked 

about their health and health care. Such 

studies can be affected by recall bias 

and general memory problems. 

Encounter-based studies have the 

advantage of including specific medical 

information about diagnosis and 

treatment provided at medical 

encounters as well as accurate counts of 

medical visits. In these respects, 

encounter-based studies add a new 

vantage point from which to evaluate 

the state of health and health care for 

U.S. women. Data from the ambulatory 

care component of the National Health 

Care Survey, conducted by the CDC’s 

National Center for Health Statistics, has 

been used to provide descriptive 

statistics on the utilization of ambulatory 

medical care resources in the United 

States. A detailed review of the variation 

in health care utilization by women of 

different ages and races using 

encounter-based data has not been 

conducted recently and is the purpose of 

this report. 

The National Ambulatory Medical 

Care Survey (NAMCS) was begun in 

1973 to collect data on the utilization of 

ambulatory medical care provided by 

office-based physicians in the United 

States. In 1992, the National Hospital 

Ambulatory Care Survey (NHAMCS) 

was begun to collect information on 

outpatient department and emergency 

department visits, to more fully provide 

information on all ambulatory care 

utilization. The surveys are 

complementary, and although the data 

collection instruments are slightly 

different for each of the three types of 

medical care settings, many items are 

the same. Areas of comparability include 

patient characteristics, patient’s reason 

for visit, expected source of payment, 

physician’s diagnosis, external cause of 

injury for injury-related visits, and 

medication therapy. Other items, for 

example diagnostic services and type of 

provider seen, are collected similarly for 

office-based physician visits and 

outpatient department visits. 

This summary report combines the 

NAMCS and NHAMCS data for 1997 

and 1998 to highlight new information 

on the use of ambulatory care medical 

visits by women in the United States. 

The timing of this report was chosen to 

highlight new data obtained due to 

changes made to the sampling universe 

and the data collection instrument used 

for NAMCS and NHAMCS in 1997. 

The purpose of these changes was to 

collect more information on services 

provided to women. Family planning 

clinics were included within the scope 

of office-based physicians for the first 

time. The data collection tool includes 

new checkboxes that specifically relate 

to issues of women: 

+ Pregnancy status was added to the 

patient characteristics section. 

+ Items for breast and pelvic 

examinations, Pap test, pregnancy 

test, and mammography and 

ultrasound were added to the 

diagnosis/screening services section. 

+ Items for family planning/ 

contraception, prenatal instructions, 

and breast self-exam were added to 

the therapeutic and preventative 

services section. 

+ Nurse-midwife was added as a 

possible provider seen. 

Detailed information on women’s 

use of ambulatory medical care is 

generally not included in the annual 

summary reports from NAMCS and 

NHAMCS. This report focuses on 

women, but also includes limited 

information on use by men for 

comparisons. The information provided 

is relevant for research into how 

differences in sex may influence health 

and treatment (5). For additional 

information on ambulatory care 

utilization, refer to the annual summary 

reports (6–11). 

Methods 

The data for this report are from 

the ambulatory care component of 

the National Health Care Survey, 

specifically NAMCS and NHAMCS. 

These are surveys of non-Federal officebased physicians and hospital 

emergency departments (ED) and 

outpatient departments (OPD) of 

short-stay and general hospitals. 

Information from a sample of visits to 

the provider during a randomly assigned 

reporting period are abstracted onto a 

one-page encounter form. The encounter 

form contains items about the 

characteristics of the patient such as 

race, sex, and age, and characteristics of 

the visit such as expected source of 

payment, physician’s diagnosis, tests 

ordered or provided, medications 

prescribed or provided, and disposition. 

The data from the 1997 and 1998 

NAMCS and NHAMCS were weighted 

to yield average annual national 

estimates of ambulatory care utilization. 

Sampling and data collection methods 

are described elsewhere (6–13). 

Data are centrally processed, 

including classification and coding of 

entries such as diagnosis and medications. 

Diagnoses were coded to the ICD–9–CM 

as were causes of injury (14). 

Therapeutic class of medications was 

coded to the National Drug Code 

Directory (15). The patient’s reason for 

visit was coded to the ‘‘A Reason for 

Visit Classification’’ (RVC) (16). In 

1997 and 1998, the NAMCS sampled 

approximately 2,500 office-based 

physicians not in the specialties of 

radiology, pathology, or anesthesiology. 

The response rate ranged between 

68–70 percent for each year and resulted 

in approximately 42,000 medical record 

abstractions. The NHAMCS data are 

obtained from approximately 485 

hospitals each year with a response rate 

between 95–97 percent. This resulted in 

about 44,000 emergency patient records 

and 60,000 OPD records for the 2 years. 

Each physician contributed 

approximately 30 patient records from a 

1-week reporting period, each ED 

contributed approximately 50 patient 

records from a 4-week reporting period, 

and each OPD contributed 

approximately 150 records during the 

same 4-week reporting period. Only 

one-half of the sampled hospitals had an 

outpatient department that included 

clinics run under the supervision of a 

physician. Ancillary clinics such as 

radiology and laboratories were 

excluded from the survey. The reporting 
Page 4 [ Series 13, No. 149 

periods for both NAMCS and 

NHAMCS were distributed across the 

entire calendar year to control for any 

temporal effects on the distribution of 

types of ambulatory care encounters. 

Each year a new sample of physicians 

was taken for the NAMCS whereas 

approximately the same set of hospitals 

was used in the NHAMCS every year. 

Sampling weights were applied to 

provide annual national estimates. The 

weights include factors representing the 

selection of the primary sampling unit 

(PSU), the hospital or physician within 

the PSU, and the visits within the 

specific provider. Adjustment factors for 

provider nonresponse are also included. 

Because of the complex sample design, 

SUDAAN was used to calculate 

standard errors for the reported 

estimates (17). In addition to sampling 

errors, the survey data are also subject 

to nonsampling error such as omissions, 

mistakes in reporting, and processing 

errors. The quality control error rate on 

diagnosis coding was 1.1 percent. See 

the Technical Notes for more details on 

the estimation process and interpreting 

sampling errors. 

The NAMCS and NHAMCS are 

record-based surveys where patients 

making multiple visits to providers have 

greater opportunities for selection. 

Therefore, the visit data must not be 

confused with person-level data. As 

such, incidence of acute or chronic 

conditions cannot be made from these 

data. However, utilization rates were 

calculated that provide the number of 

ambulatory care visits per 100 persons 

living in the United States. The 

denominators for population rates are 

based on an average of the U.S. civilian, 

noninstitutionalized population of July 

1, 1997, and July 1, 1998, adjusted for 

census underenumeration (see Technical 

Notes). The population rates for totals of 

all age groups have been age-adjusted to 

the 2000 standard. 

For the purposes of this report, 

estimation of ambulatory medical care 

by women was based on encounter 

records for females who were at least 15 

years old at the time of the sampled 

visit. Because the age of the woman is 

directly related to utilization, visits were 

categorized into three age groups; 15–44 

years, 45–64 years, and 65 years and 

older. Many of the tables also present 

results separately for visits made by 

white and black women. There were too 

few visits sampled to make separate 

detailed estimates for women of other 

racial backgrounds. Analyses by 

Hispanic origin could not be made due 

to the large proportion of records with 

missing data on ethnicity. The Technical 

Notes also include the physician 

specialties that were aggregated to 

differentiate between primary care, 

surgical and nonsurgical specialties that 

are used in several of the analyses used 

in the report. 

Results 

Overall, approximately 500 

million visits to ambulatory care 

medical providers were made by 

women 15 years of age and over each 

year in 1997 and 1998. This represents 

an age-adjusted annual rate of 4.6 visits 

per woman. Selected patient, provider, 

and visit characteristics for these visits 

are described in the following text. 

Patient Characteristics 

While 46 percent of all ambulatory 

medical care visits by women 15 years 

of age and over were made by younger 

women (15–44 years of age), the 

utilization rate increased with age 

(table 1). The rate of visits by women 

65 years of age and over was 87 percent 

higher, and the rate of visits by women 

45–64 years of age were 25 percent 

higher than the rate of visits by women 

15–44 years of age (3.8 visits per 

woman). The rate of use by white, 

black, and Asian/Pacific Islander (data 

not shown) women were similar. 

0 10 0 0 40 0 60 70 0 0 100 

65 years and 

over 

45-64 years 

15-44 years 

Primary care providers 

Surgical 

specialists 

Nonsurgical 

specialists 

Outpatient 

Department 

Emergency 

Department 

Percent of visits 

Office-based providers 

2 3 5 8 9

Figure 1. Women’s ambulatory care visits by specialty, place of care, and age 
General and family 

medicine 

25% 

Obstetrics and 

Gynecology 

18% 

Ophthalmology 

7% 

All other 

28% 

Orthopedic 

surgery 

4% 

Internal medicine 

18% 

Figure 2. Women’s office-based physician visits by physician’s specialty 

Provider Characteristics 

When only categorizing providers 

as office-based, hospital outpatient 

departments and emergency rooms, 

more than four out of five ambulatory 

care visits in 1997–98 by women 15 

years of age and over were to 

office-based physicians. The remaining 

visits were equally split between 

hospital outpatient departments and 

emergency departments (table 2). The 

distribution of visits to various providers 

varied by patient’s age, however, with 

younger women more likely to make 

visits to primary care physicians and 

emergency departments compared with 

older women (65 years of age and over), 

who had a relatively higher probability 

of making visits to physicians in 

surgical and nonsurgical specialties 

(figure 1) (see Technical Notes for 

explanation of categories used). 

Providers were then broken down 

into specialties within each of the major 

provider categories (table 2). Among 

visits by women to office-based 

physicians, the majority were to either 

general and family practice physicians 

(25 percent), internal medicine 

physicians (18 percent), or obstetricians 

and gynecologists (18 percent). 

Ophthalmology was the next most 

common practice type, accounting for 

7 percent of all office-based visits 

(figure 2). Among visits to hospital 

outpatient departments, 65 percent were 

to general medicine clinics, while 

16 percent were to obstetric/gynecology 

clinics. 

Most women, regardless of age or 

race, saw a physician during medical 

ambulatory care visits. Almost 

95 percent of all visits by women 

involved being seen by a physician. 

However, women were also likely to see 

additional medical providers, such as a 

registered nurse (17 percent of visits), 

licensed practical nurse (11 percent of 

visits), or a medical/nursing assistant 

(23 percent of visits) (table 3). 

Series 13, No. 149 [ Page 5 

Visit Characteristics 

Primary Expected Source of 

Payment 

The most frequent sources of 

payment for ambulatory care visits by 

women were private insurance 

(50 percent), Medicare (22 percent), and 

Medicaid (9 percent) (table 4). 

Large differences in the rate of 

visits by primary source of payment 

were observed between black and white 

women (figure 3). The proportion of 

visits covered by private insurance was 

1.3 times as high among white women 

as among black women. In contrast, the 

proportion of ambulatory visits by black 

women covered by Medicaid was more 

than three times as high as the 

proportion of Medicaid visits by white 

women. 

Almost one-quarter of ambulatory 

care visits were made by women who 

were members of a health maintenance 

organization (HMO). Visits by older 

women (65 years of age and older) were 

less likely to be made by HMO 

members than younger women (data not 

shown), although this is most likely a 

function of the limited availability of 

Medicare/HMO plans. 

Reason for Visit 

The major reason for visit item on 

the physician office and OPD data 

collection instrument collects 

information on the general nature of the 

ambulatory care visit—whether for an 

acute problem; routine chronic problem; 

flare-up of a chronic problem; pre- or 

post-surgery visit, or injury followup, or 

for non-illness care including routine 

medical examinations and prenatal care. 

The most frequently cited reasons for 

office-based and outpatient hospital 

ambulatory care visits were chronic 

conditions (39 percent), acute conditions 

(31 percent), and non-illness and 

preventive care (21 percent) (table 5). 

The percentage of ambulatory care 

visits for both acute care and 

non-illness/preventive purposes by 

women decreased with age, while 

chronic condition and pre/post surgery 

visits increased with age. For example, 

among visits by women 15–44 years of 
Page 6 [ Series 13, No. 149 

0 

50 

100 

150 

200 

250 

Expected source of payment 

Visits per 100 women (age-adjusted) 

Private insurance Medicare Medicaid Other/unknown 

White Black 

Figure 3. Age-adjusted female visit rates by expected source of payment and race 

age, 27 percent of visits were for 

chronic conditions compared with 

51 percent for chronic conditions in the 

65 and older age group. Thirty-one 

percent of visits for women ages 15–44 

were for non-illness reasons compared 

with 10 percent of visits in the 65 and 

older age group (figure 4). This is 

consistent with the changes in type of 

provider seen by older and younger 

women (figure 1). 

The principal reason for visit is the 

most important problem, complaint, or 

reason for the visit as reported by the 

patient. The specific reasons for 

ambulatory visits cited by women most 

often were general medical examination 

(7 percent of total adult female visits), 

routine prenatal examination (6 percent), 

and progress visit (4 percent) (table 6). 

As seen in figure 5, the proportion of 

visits for the most common reasons for 

visit varied little by age, except for 

prenatal care and vision dysfunction. 

Prenatal care represented 12 percent of 

all visits among women 15–44 years of 

age and was the second most common 

reason for visit for all ages. 

The 1997 and 1998 NAMCS and 

NHAMCS data form included a 

checkbox on pregnancy status. The 

0 20 0 60 0 100 

Nonillness 

Pre/ 

postChronic condition surgery

Percent of visits 

Acute condition 

15-44 years 

45-64 years 

65 years and 

over 

4 8

Figure 4. Women’s major reason for visit by age 
Series 13, No. 149 [ Page 7 

0 

2 

* 

*Category not applicable. 

4 

6 

8 

10 

12 

14 

General 

medical exam 

Prenatal 

exam 

Stomach/ 

abdominal 

Cough Vision 

disfunction 

Percent of visits 

15-44 years 45-64 years 65 years and over 

status was missing for approximately 

28 percent of visits by women of 

child-bearing age, it is possible that the 

pregnancy information was recorded on 

the NAMCS/NHAMCS form only if the 

physician or hospital staff thought it 

pertinent to the visit (that is, 

pregnancy-related diagnosis). 

Diagnostic Groups 

Physician’s diagnoses differ from 

patent’s reasons for visit in the source 

of data and in the coding scheme used. 

Diseases and conditions, rather than 

symptoms, are obtained and general 

issues such as general physical 

examination are not as frequently noted. 

The most common diagnostic groups 

Figure 5. Women’s specific reason for visit by age 

reason for visit for 70 percent of all (6 percent) and problems of pregnancy 

visits by women noted as being (2 percent) were the next most common 

pregnant was routine prenatal care reasons for visits among pregnant 

(figure 6). General medical examinations women. However, since pregnancy 

Problems 

with 

pregnancy 

3% 

General medical exam 

6% 

All other 

21% 

Routine prenatal exam 

70% 

Figure 6. Reason for visit by pregnant women 

noted were normal pregnancy 

(6 percent), essential hypertension 

(4 percent), and arthropathies (3 percent) 

(table 7). 

The rate of visits by white women 

differed substantially from that of black 

women on some of the most frequently 

noted diagnostic groups (figure 7). 

Compared with the rate of visits by 

white women, the rate of visits by black 

women with diagnoses of hypertension 

was 83 percent higher, the rate of visits 

for complications of pregnancy was 

81 percent higher, the rate of visits with 

diagnoses of arthropathies (for example, 

osteoarthrosis) was 50 percent higher, 

and the rate of visits with diagnoses of 

diabetes was 138 percent higher. These 

racial discrepancies increase as women 

age. Compared with younger white 

women, younger black women had more 

visits for childbirth complications (17.5 

and 9.6 per 100 women) and 

inflammatory pelvic disorders (11.2 and 

5.2 per 100 women). White women 

between 45–64 years of age were more 

likely than black women to make visits 

for menopause-related conditions (11.3 

and 4.0 visits per 100 women, 

respectively). They were also more 

likely to make visits for cataracts but 

less likely to make them for glaucoma. 

By age 65 years and older, white 

women were twice as likely as black 

women to make a cataract visit (31.3 

versus 15.4 visits per 100 women), and 

three times as likely to make visits for 

ischemic heart disease (23.9 visits 

versus 7.6 visits per 100 women). It is 
Page 8 [ Series 13, No. 149 

0 

5 

10 

15 

20 

25 

30 

Normal 

pregnancy 

Essential 

hypertension 

Arthropathies Acute URI Diabetes Rheumatism Complications 

of pregnancy 

Rate per 100 women (age-adjusted) 

White Black 

Figure 7. Age-adjusted female visit rates for selected diagnostic groups by race 

interesting to note that the utilization 

rates for general medical exams and 

gynecological exams are higher for 

senior black women compared with 

white women, while white women make 

more visits for preventive exams at 

younger ages. 

Injury-Related Visits 

In 1997–98, injury- and poisoningrelated visits represented 11 percent of 

all ambulatory care visits by women. 

Approximately 54,611,000 visits were 

made due to injury or poisonings 

(table 8). 

As a percentage of all annual 

ambulatory visits, injury-related office 

visits by women declined somewhat 

with age. Rates of injury-related office 

visits per 100, however, increased with 

age. Rates of injury-related visits 

increased from 46 visits per 100 in the 

15–44 age group to 66 visits per 100 in 

the 65 and over age group—a 43 percent 

increase (figure 8). 

Although 27 percent of all 

injury-related visits were missing 

information on place of occurrence, the 

data suggest that the home is one of the 

most frequent places of injury for 

women. Approximately 11 million 

ambulatory care visits by women 

involved injuries that occurred in the 

home, a rate of over 10 visits per 100 

women. Streets or highways were the 

second most frequent place of injury, at 

a rate of 6 visits per 100 women 

(table 9). It should be noted that one 

injury may result in multiple health care 

encounters for diagnosis and treatment. 

The leading cause of injury visits 

by women were falls (17.2 percent) and 

motor vehicle crashes (11.2 percent) 

(table 9). The nature of the injuries at 

ambulatory visits by women varied only 

slightly by race. Senior white women 

were more likely to make ambulatory 

visits for bone fractures compared with 

black women; however, middle-aged 

black women were more likely than 

white women to make visits for sprains 

and strains. The visit rate for intentional 

injuries was higher for young black 

women compared with white women 

(3.5 versus 1.7 visits per 100 women, 

respectively). The majority of these 

injuries were from assaults as opposed 

to self-infliction or suicide attempts 

(data not shown). 

0 

20 

40 

60 

80 

15-44 years 45-64 years 65 years and over 

Rates per 100 women 

White Black 

Figure 8. Age-adjusted female visit rates of injury visits by age and race 
0 0 20 30 40 50 60 70 80 90 

Breast 

Pelvic 

PAP test 

Mammography 

Vision 

Glaucoma 

Hearing 

Cholesterol 

x ray 

NOTE: EKG is electrocardiogram. 

EKG 

Rate per 100 women 

15-44 years 45-64 years 65 years and over 

Selected diagnostic and screening services 

1

Figure 9. Female visit rates for selected diagnostic and screening services by age 

Diagnostic and Screening some type of diagnostic or screening 

Services service ordered or provided (table 10). 

The most common procedure performed 

Four out of five visits to physician during visits was blood pressure 

offices and outpatient departments by screening, which women in 56 percent 

of all visits received. Other common 

women 15 years of age and over had 

diagnostic and screening procedures 

Series 13, No. 149 [ Page 9 

received were pelvic exams (14 percent) 

and urinalysis (14 percent) (table 10). 

The rate of visits with screening 

and diagnostic services increased with 

age (figure 9). The rate for most of the 

specific types of tests and screening also 

increased with age. This is especially 

true of vision, glaucoma, and cholesterol 

screening, and use of EKG and x-rays. 

Some tests do not increase with age, but 

they are mostly gynecologic and 

reproductive procedures that one would 

not expect to increase with age, such as 

pelvic exams and pap tests. The rate of 

mammography use among women 65 

years of age and over is 29 percent 

lower than the rate for women 45–64 

(19.3 versus 27.1 visits per 100 women), 

which would not be expected based on 

recommendations for use. 

Therapeutic and Preventive 

Services 

Only 41 percent of visits by women 

15 years of age and over to office-based 

physicians and hospital outpatient 

departments received one or more 

therapeutic or preventive services. Diet 

(15 percent) and exercise (11 percent) 

counseling were the two most common 

types of services offered in this 

category. Prenatal instructions 

(5 percent) and breast self-examination 

(4 percent) were next (table 11). 

The rate of visits in which 

counseling/education was included 

tended to increase with age. For 

example, the rate of visits by women 65 

years of age and over during which diet 

education was included was 107 percent 

higher than that for women 15–44 years 

of age. The same was true for exercise 

education (95 percent higher for visits 

among women in the oldest age group) 

and skin cancer education (187 percent 

higher). However, counseling/education 

regarding breast self-examination and 

psychopharmacotherapy did not increase 

with age (figure 10). 

Medication Therapy 

Physician office and hospital staff 

were instructed to record all new or 

continued medications ordered, 

administered, or provided at the visit, 
Page 10 [ Series 13, No. 149 

0 

20 

40 

60 

80 

100 

120 

Diet Exercise Skin cancer Breast self-exam Psychopharmacotherapy 

Physiotherapy 

Rate per 100 women 

15-44 years 45-64 years 65 years and over 

Figure 10. Female visit rates where selected therapeutic and preventive services were provided by age 

including prescription and term ‘‘medication.’’ Visits with one or 

nonprescription preparations, more drug mentions are termed ‘‘drug 

immunizations, and desensitizing agents. visits’’ in NAMCS and NHAMCS. Up 

As used in NAMCS and NHAMCS, the to six medications were captured for 

term ‘‘drug’’ is interchangeable with the each visit. 

0 

50 

100 

150 

200 

250 

15-44 years 45-64 years 65 years and over 

Rate per 100 women 

0 1 2 4 or more 

Number of drug mentions 

3 

Figure 11. Female visit rates by number of drug mentions and age 

Two out of three ambulatory care 

visits made by women had medications 

provided or prescribed. Older women 

were more likely to have drugs provided 

or prescribed during ambulatory care 

visits and were also more likely to have 

multiple drugs provided or prescribed, 

compared with younger women 

(table 12). Compared with women 

15–44 years of age, the rate of visits by 

women 65 years of age and over with 

zero or one drug mention was about 

40 percent higher, with two drug 

mentions was 70 percent higher, 1.7 

times higher with three drug mentions, 

and 7.5 times as high with four or more 

drug mentions (figure 11). Women 

15–44 years of age averaged 1.1 drug 

mentions per visit whereas middle-age 

women averaged 1.6 and senior women 

averaged 1.9 drug mentions per 

ambulatory care visit. The percent of 

visits with four or more drug mentions 

increased for each age group as well, 

from 5 percent among visits by younger 

women to 20 percent for visits by senior 

women. 

When tabulating generic substances 

prescribed, drug products containing 

more than one ingredient (combination 

products) are included in the data for 

each ingredient. For example, 
0 2 3 4 5 

Calcium channel blockers 

Blood glucose regulators 

Antiasthmatics/bronchodilators 

Vitamins/minerals 

Antihistamines 

Therapeutic classification 

Disorders, acid/peptic 

Nonsteroidal anti-Inflammatory 

drug 

Estrogens/progestins 

Antidepressants 

Analgesics, nonnarcotic 

Percent of visits 

1 

Figure 12. Percent of drug mentions among female ambulatory care visits for top 

therapeutic classes 

White Black White Black White Black 

0 

20 

40 

60 

80 

100 

120 

Mentions per 100 women 

Calcium channel blockers ACE Inhibitors Beta blockers 

15-44 years 45-64 years 65 years and over 

Figure 13. Female prescription rates for selected cardiovascular drugs by age and race 

acetaminophen with codeine is included 

in the count for acetaminophen and the 

count for codeine. Acetaminophen and 

estrogen were the two generic 

substances most frequently used in 

drugs ordered or provided during 

ambulatory care visits by women of all 

ages, occurring in 3.6 percent and 

2.2 percent of drug mentions, 

respectively (table 13). 

Age of the patient greatly 

influenced the types of generic 

substances ordered or provided. Visits 

by women 15–44 were more likely to 

include various vitamins, probably 

during prenatal care visits, after 

Series 13, No. 149 [ Page 11 

acetaminophen. Estrogen was the 

generic substance most often ordered or 

provided during ambulatory care visits 

by women 45–64 years of age, with 

progesterone third most common. In the 

oldest age group, substances used to 

treat hypertension and heart disease 

were very common along with 

substances for pain and estrogen. 

Drug mentions are shown by 

therapeutic class in figure 12. This 

classification is based on the therapeutic 

categories used in the National Drug 

Code Directory, 1995 edition (NDC) (8). 

It should be noted that some drugs have 

more than one therapeutic application. 

In these cases, the drug was classified 

under its primary therapeutic use. Drugs 

for the cardiovascular-renal system, 

hormones, and central nervous system 

were the top classes of drugs used by 

women 15 years of age and over in 

1997–98, when analyzed using only the 

20 major classifications. When the 

detailed classes of drugs are analyzed, 

nonnarcotic analgesics, antidepressant, 

and estrogen/progestin were the three 

most common types of medications 

mentioned (table 14). The top 10 

therapeutic classes accounted for 

35 percent of all drug mentions at 

women’s visits. 

There are major differences in the 

prescription pattern by patient age. The 

rate of cardiovascular-renal system class 

drug mentions increased with age. For 

example, compared with visits by 

women 15–44 years of age, calcium 

channel blockers are prescribed 4.6 

times more often during visits by 

women 45–64 years of age, and 15.4 

times more often during visits by 

women 65 years and older. However, 

there is also a large difference in use by 

race within each age category, with 

black women much more likely to 

receive cardiovascular-renal system 

medications than white women 

(figure 13). The rates were substantially 

higher in the older age group but are 

less discrepant by race. The same 

pattern holds in visit rates with 

prescriptions for the diabetes-related 

medications of blood glucose regulators 

(excluding insulin) and diuretics 

(figure 14). For insulin, however, the 

race discrepancy increases with age. 

Prescription rates per population of 
Page 12 [ Series 13, No. 149 

White Black White Black White Black 

0 

20 

40 

60 

80 

100 

Mentions per 100 women 

Blood glucose regulators 

(excluding insulin) 

Diuretics Insulin 

15-44 years 45-64 years 65 years and over 

men (figure 16). It is important to note 

that the people in nursing homes receive 

care within the nursing home for the 

types of conditions other people seek 

ambulatory medical care, and most 

nursing home residents are women (18). 

The difference in the rate of 

ambulatory care visits by women and 

men was most pronounced among visits 

to primary care physicians when place 

of care was being evaluated (figure 17). 

The rate of visits by women was 

58 percent greater than the rate of visits 

Figure 14. Female prescription rates for selected diabetes-related drugs by age and race 

White Black White Black 

0 

10 

20 

30 

40 

50 

Mentions per 100 women 

Antidepressants Antianxiety agents 

15-44 years 45-64 years 65 years and over 

Figure 15. Female prescription rates for antidepressants and antianxiety agents by age and 

race 

antidepressants and antianxiety 

medications, the two most common 

central nervous system class 

medications, were higher for white 

women than black women, although 

again the disparity was highest in the 

young age group, while the rates were 

higher at older ages (figure 15). These 

differences in prescription rates per 

population parallel differences in 

diagnoses as noted on table 7. 

Comparison of Ambulatory 

Care by Women and Men 

In order to compare women’s and 

men’s use of ambulatory medical care, 

visits which had physician diagnoses 

related to pregnancy (ICD–9–CM codes 

630–677, V22–V24) were excluded. 

Some women who were pregnant will 

be in these analyses, but not all visits by 

pregnant women are related to their 

pregnancy. 

Regardless of race, the overall rate 

of ambulatory care use among women 

with nonpregnancy-related diagnoses 

was 33 percent higher than that for men. 

However, the difference in 

nonpregnancy ambulatory care visits by 

women and men decreased with age. 

The rate of visits by women 15–44 

years of age was about 56 percent 

greater than the rate for men in this age 

group. However, among people 65 years 

of age and over, the rate of visits by 

women was fairly similar to the rate for 

by men to this type of office-based 

physician. The rate of visits to 

outpatient departments was 40 percent 

higher among women than among men. 

Utilization rates categorized by 

major reason for visit disclose that while 

the visit rates by women were at least 

somewhat higher for all types of care, 

the rate of visits for preventive care and 

other non-illness reasons are the most 

disparate by sex (figure 18). The rate of 

visits by women for non-illness was 

100 percent higher than among men, 

after controlling for age and removing 

pregnancy-related visits. 

Figure 19 displays the age-adjusted 

rates of drug mentions during 

ambulatory care visits by women and 

men for the top eight major classes of 

drugs among women and men, although 

the ordering is different by sex. As 

would be expected, there are more drug 

mentions per population among women 

than there are men, since there are more 

visits per population. 

The most striking differences in the 

rate of drug mentions by sex is 

medications with hormones/hormonal 

mechanisms, as expected, and central 

nervous system mechanisms. The most 

frequent classes of drugs prescribed for 

women are displayed in table 15. 

Estrogen/progestin and contraceptives 

are the most common for women. 

Antidepressants are the second most 

common class of drug mentioned during 

visits by women but are not commonly 

prescribed for men. They account for 

49 percent of all CNS medication 

mentions. The age-adjusted rate of 

antidepressant mentions among women 

is 95 percent of the rate of all CNS 

medication mentions in visits by men. 
Series 13, No. 149 [ Page 13 

0 

100 

200 

300 

400 

500 

600 

700 

800 

15-44 years 45-64 years 65 years 

and over 

White Black 

Rate per 100 people 

Women Men 

Figure 16. Visit rates of women with nonpregnancy diagnoses and men by age and race 

0 

50 

100 

150 

200 

250 

Primary care Surgical care Nonsurgical 

care 

Outpatient 

department 

Emergency 

department 

Rate per 100 person 

Women Men 

Figure 17. Visit rates by place of care for women with nonpregnancy diagnoses and men 

Discussion 

I

n general, the rate of ambulatory 

medical care visits by women 

increased with age. This is true 

overall and within different ambulatory 

care settings, providers, and types of 

care. While women over the age of 65 

years represent 18.5 percent of the adult, 

female U.S. uninstitutionalized civilian 

population, their medical encounters 

represent 26.5 percent of all ambulatory 

encounters by women, and therefore 

visits by this group of women has a 

large influence on overall utilization 

patterns. 

Several exceptions to this general 

trend by age have been noted. First, use 

of obstetricians/gynecologists goes down 

dramatically with age, from 100 visits 

per 100 women per year among the 

youngest age group, to 21 visits per 100 

women among senior women. It is not 

surprising that use is high in the 

youngest age group for which obstetric 

care is a major reason for medical visits. 

However, since few older women are 

visiting obstetricians/gynecologists, the 

recommendations for women of all 

ages to receive female cancer 

screening (19,20) means physicians of 

other specialties need to provide these 

gynecological services. 

The utilization rate for non-illness 

and preventive care purposes decreases 

42 percent between the youngest and 

middle-age groups, and then levels off. 

Presumably, some of this is due to the 

large number of prenatal care visits that 

women of reproductive age make. 

Clinical breast examinations 

occurred at approximately the same rate 

for every age group, roughly 50 visits 

per 100 women per year. The rate of 

visits during which mammography was 

ordered or provided also did not 

significantly vary by age among women 

45 years of age and over, although 

younger women had lower use. 

Within physician offices, utilization 

of various medical and surgical 

specialists increased much more 

dramatically with patient age than the 

utilization of primary care specialists. 

Women are seeking more specialized 

care for their conditions. Such 

specialties would include 
Page 14 [ Series 13, No. 149 

0 

20 

40 

60 

80 

100 

120 

140 

160 

180 

Acute 

condition 

Chronic 

condition 

Pre/postsurgery Nonillness Unknown 

Rate per 100 persons 

Women Men 

Figure 18. Visit rates by major reason for visit for women with nonpregnancy diagnoses 

and men 

0 20 40 60 80 100 120 140 

All others and 

unclassified 

Skin/mucous 

membrane 

Metabolic/nutrients 

Antimicrobial 

agents 

Central nervous 

system 

Respiratory track 

Relief of pain 

Hormones/hormonal 

mechanisms 

Cardiovascular-renal 

drugs 

Rate per 100 persons 

Therapeutic classification 

Women Men 

Figure 19. Prescription rates by major therapeutic classes for women with nonpregnancy 

diagnoses and men 

ophthalmologic, cardiovascular, and 

rheumatoid specialties for treating the 

increased incidence in older women of 

eye problems such as cataracts and 

glaucoma, circulation problems such as 

hypertension and heart disease, and 

muscular/joint problems such as arthritis 

and osteoporosis. 

Black women are being seen for 

several chronic conditions at far greater 

rates than white women. These 

conditions include arthropathies, 

hypertension, and diabetes. These are 

three of the five leading conditions that 

are associated with disability among the 

elderly of all races (21). The 

NAMCS/NHAMCS data indicated that 

the rate of visits for black women 

compared with white women were 

85 percent higher for hypertension, 

50 percent higher for arthritis, and 

138 percent higher for diabetes. The 

prevalence of these conditions, as 

measured in the National Health 

Interview Survey (NHIS) data, adjusting 

to the same population standard for the 

same 2-year period, was somewhat less 

divergent; black women were 59 percent 

more likely to have been diagnosed with 

hypertension, 103 percent more likely to 

have been diagnosed with diabetes, and 

no more likely to report joint pain in the 

past year than white women (22). This 

may indicate that these conditions are 

more advanced or debilitating in black 

women. While Medicare covers many 

medical services for older adults, 

previous research has demonstrated that 

financial, personal, and physical barriers 

create disparities in health status and 

health care usage (23). Investigations of 

the reason why the discrepancy in the 

rate of visits for these and probably 

other conditions are higher than the 

discrepancy in prevalence are needed. 

Counseling and screening of several 

types are recommended by several 

organizations as ways to prevent 

disease. For example, many groups, 

including the U.S. Preventive Services 

Task Force (USPSTF) recommend that 

clinicians routinely counsel patients to 

promote a healthy diet and include 

regular exercise (20). The USPSTF also 

recommends that clinicians counsel 

smokers every time they are seen to quit 

smoking (20). The NAMCS/NHAMCS 

data presented indicate that diet 
Series 13, No. 149 [ Page 15 

counseling is done fairly routinely, while 

exercise counseling is done less often, 

and smoking counseling, at a rate of 12 

visits per 100 women, was done far less 

than once a year among smokers (the 

current proportion of women who 

smoke being 22 percent (24)). The rate 

of visits including mammography 

among women 45 and over averaged 

between 20–27 visits per 100 women, 

while annual mammography is 

recommended for women 50–69 years 

of age (20). Pap tests are recommended 

every 3 years, however, which is 

roughly what the NAMCS/NHAMCS 

data show. 

Data obtained from self-report 

indicate that 56 percent of women 45–64 

years of age and 48 percent of women 

65 years and over have had a 

mammogram in the previous year (25). 

This rate of mammography use from 

encounter records is lower than would 

be expected, and includes repeat 

mammograms in some cases. Part of the 

difference can be accounted for by use 

of mammography in locations not 

included in NAMCS/NHAMCS, such as 

mobile health units and work-site health 

units. Self-report of mammography use 

may also not reflect actual use (26, 27). 

Mental health issues are cause for a 

substantial proportion of ambulatory 

care visits by women, as demonstrated 

by medication use. The rate of visits 

that included mental health counseling 

was relatively similar at all ages, unlike 

the rise in rates of most other 

therapeutic and preventive services, and 

was included in only 2.8 percent of all 

visits by women. The rate of visits to 

psychiatrists was 10.6 per 100 younger 

women, 16.2 per 100 middle-aged 

women, and then dropped to 8.0 per 100 

senior women. Medications for mental 

health were frequently mentioned. 

Antidepressants were the second most 

common specific class of drug 

mentioned during visits, even though 

antidepressants may be underutilized for 

people with depression in the United 

States in general (28, 29). Furthermore, 

the mentions of CNS drugs increased 

with age. Among women 15–44 years of 

age, the rate of visits with any CNS 

medication prescription was 43.3 per 

100 women, but it was 96 percent 

higher among women 45–64 years of 

age and 120 percent higher among 

women 65 years of age and older. There 

was a large difference noted by race, 

with the rate of visits with mental health 

counseling by white women being 

41 percent higher than the rate of visits 

by black women. A similar difference by 

race in the rate of visits with CNS 

prescriptions was found (45 percent 

higher among white women than black 

women, controlling for age). However, 

the NHIS data indicate that black 

women are 19 percent more likely to 

report that mental health issues 

interfered with their life a lot in the past 

30 days (22). Mental health issues may 

require many ambulatory care visits for 

the same condition, and the 

NAMCS/NHAMCS data cannot be used 

to estimate the prevalence of mental 

health conditions. Nationally 

representative data on mental health 

issues are rare (30). This data source, 

while not ideal, is at least one measure 

of the extent of these issues. 

Use of ambulatory care by women 

was higher than for men, even after 

removing visits related to pregnancy. 

There are many possible explanations 

for this. Women’s self-reported health is 

worse than men’s (31), on average, 

which may either reflect more illness or 

differences in the way health is viewed 

or discussed by women. Older women 

are more likely to have disabling 

conditions than older men (21). There 

are more women in the oldest age 

categories (21), and health care is used 

in the oldest ages at the highest rates. 

Women generally are responsible for 

their family’s health (32) and so may 

think about health care needs more than 

men. They are more likely to have a 

usual source of care (24), which is a 

strong predictor of health care 

utilization. They also tend to use 

medical care for screening and health 

education more often than men (33). 

Women have been said to also be more 

likely to report and act on illness, 

although research has not always born 

this out (34, 35). 

Because this report looks at visits, 

rather than people, conclusions should 

be made with caution. Multiple 

ambulatory care visits for the same 

condition make it impossible to use 

these data to measure prevalence of 

conditions or medication use. 

Furthermore, the average number of 

visits vary by condition type. As an 

example, a single pregnancy is likely to 

cause far more visits than the flu. Data 

from the NHIS indicate that 12 percent 

of women did not make any ambulatory 

medical visits during the time period 

studied in this report. However, among 

women under age 65, black women 

were more likely than white women to 

have had no nonemergency ambulatory 

care (22). Additional problems arise 

when analyzing medication encounters 

since new or continuing medications are 

collected in this survey, meaning that 

medications that are used chronically 

will be counted on multiple visits and 

may be unrelated to the purpose of the 

visit. Thus, medications for chronic 

conditions are likely to be counted many 

times for the same person while 

medications for acute conditions will be 

counted during fewer visits. 

In summary, women make 

approximately one-half billion visits 

annually for ambulatory medical 

services. Utilization of ambulatory care 

services varied by patient age and in 

some cases by race as well. Factors that 

might explain the observed variation in 

utilization include variation in incidence 

of conditions and access to care, neither 

of which can be addressed using 

NAMCS and NHAMCS data, and so 

will require additional research. Given 

the higher proportion of ambulatory care 

visits made by women, the information 

presented should be useful not only to 

inform women’s health policy, but 

health care policy as a whole. 

Additional Information 

Ambulatory care visit and drug data 

from NAMCS and NHAMCS are 

available in a variety of formats 

including public-use data tapes, 

CD-ROMs, and downloadable data files 

accessed through the NCHS homepage 

on the Internet. For additional 

information concerning this report, 

future or previous reports, or NAMCS 

and NHAMCS data, inquiries may be 

directed to the Ambulatory Care 

Statistics Branch at (301) 458–4600, or 

visit the Web site at www.cdc.gov/nchs/ 

about/major/ahcd/ahcd1.htm. 
Page 16 [ Series 13, No. 149 

References 

1.	 U.S. Department of Health and Human 

Services. Women’s health: Report of 

the Public Health Service Task Force 

on Women’s Health Issues. (PHS) 

85–5026. Washington, DC: Department 

of Health and Human Services, Public 

Health Service, 1985. 

2.	 Public Health Service. National 

Institutes of Health. Opportunities for 

research on women’s health. Report 

from the Conference in Hunt Valley, 

Maryland, September 4–6, 1991. NIH 

Publication No. 92–3457. Bethesda, 

Maryland: U.S. Department of Health 

and Human Services. 1992. 

3.	 Office of Women’s Health, Centers for 

Disease Control and Prevention. All the 

stages of our lives. Atlanta, Georgia. 

Spring 2000. 

4.	 Muller CF. Health care and gender. 

Russell Sage Foundation: New York. 

1992. 

5.	 Public Health Service, National 

Institutes of Health. Agenda for 

research on women’s health for the 

21st century. A report of the Task Force 

on the NIH Women’s Health Research 

Agenda for the 21st Century, vol 1. 

Executive summary. NIH Publication 

No. 99–4385, Bethesda, Maryland: U.S. 

Department of Health and Human 

Services. 1999. 

6.	 Woodwell DA. National Ambulatory 

Medical Care Survey, 1997 summary. 

Advance data from vital and health 

statistics; no 305. Hyattsville, 

Maryland: National Center for Health 

Statistics. 1999. 

7.	 Woodwell DA. National Ambulatory 

Medical Care Survey, 1998 summary. 

Advance data from vital and health 

statistics; no 315. Hyattsville, 

Maryland: National Center for Health 

Statistics. 2000. 

8.	 McCaig LF. National Hospital 

Ambulatory Medical Care Survey, 1997 

Outpatient Department Summary. 

Advance data from vital and health 

statistics; no 309. Hyattsville, 

Maryland: National Center for Health 

Statistics. 1999. 

9.	 Slusarcick AL, McCaig LF. National 

Hospital Ambulatory Medical Care 

Survey: 1998 outpatient department 

summary. Advance data from vital and 

health statistics; no 317. Hyattsville, 

Maryland: National Center for Health 

Statistics. 2000. 

10.	 Nourjah, P. National Hospital 

Ambulatory Medical Care Survey: 1997 

emergency department summary. 

Advance data from vital and health 

statistics; no 304. Hyattsville, 

Maryland. National Center for Health 

Statistics. 1999. 

11. McCaig L. National Hospital 

Ambulatory Medical Care Survey: 1998 

emergency department summary. 

Advance data from vital and health 

statistics; no 313. Hyattsville, 

Maryland: National Center for Health 

Statistics. 2000. 

12.	 Schappert SM. Ambulatory care visits 

to physician offices, hospital outpatient 

departments and emergency 

departments: United States, 1997. 

National Center for Health Statistics. 

Vital and Health Stat 13(143) 1999. 

13.	 McCaig LF, McLemore T. Plan and 

operation of the National Hospital 

Ambulatory Medical Care Survey. 

National Center for Health Statistics. 

Vital Health Stat 1(34). 1994. 

14.	 Public Health Service and Health Care 

Financing Administration. International 

Classification of Diseases, 9th revision, 

Clinical Modification, 6th ed. 

Washington, DC: Public Health 

Service. 1998. 

15.	 Food and Drug Administration. 

National Drug Code Directory, 1995 

edition. Washington: Public Health 

Service. 1995. 

16.	 Schneider D, Appleton L, McLemore T. 

A reason for visit classification for 

ambulatory care. National Center for 

Health Statistics. Vital and Health Stat 

2(78). 1979. 

17.	 Shah BV, Barnwell BG, Hunt PN, 

LaVange LM. SUDAAN user’s manual, 

release 5.50. Research Triangle Park, 

North Carolina. Research Triangle 

Institute. 1991. 

18.	 Dey AN. Characteristics of elderly 

nursing home residents: Data from the 

1995 National Nursing Home Survey. 

Advance data from vital and health 

statistics; no 289. Hyattsville, 

Maryland: National Center for Health 

Statistics. 1997. 

19.	 American Cancer Society: Guidelines 

for the cancer-related checkup. Atlanta, 

Georgia: American Cancer Society. 

1998. 

20.	 U.S. Preventive Services Task Force. 

Guide to Clinical Preventive Services, 

2nd ed. Alexandria, Virginia: 

International Medical Publishing. 1996. 

21.	 Kramarow E, Lentzner H, Rooks R, 

Weeks J, Saydah S. Health and Aging 

Chartbook. Health, United States, 1999. 

Hyattsville, Maryland: National Center 

for Health Statistics. 1999. 

22.	 National Center for Health Statistics. 

Internal Use Tape Documentation, 

National Health Interview Survey, 1997 

and 1998 (machine readable data file 

and documentation). National Center 

for Health Statistics, Hyattsville, 

Maryland. 

23.	 Janes GR, Blackman DK, Bolen JC, 

Kamimoto LA, Rhodes L, Caplan LS, 

et al. Surveillance for use of preventive 

health-care services by older adults, 

1995–97. MMWR. Surveillance 

Summaries 48(8): 51–88. 1999. 

24.	 National Center for Health Statistics. 

Health, United States, 2000 with 

Adolescent Health Chartbook. 

Hyattsville, Maryland: 2000. 

25.	 National Center for Health Statistics. 

Internal Use Tape Documentation, 

National Health Interview Survey, 1998 

(machine readable data file and 

documentation). National Center for 

Health Statistics, Hyattsville, Maryland. 

26.	 Thompson B, Taylor V, Goldberg H, 

Mullen M. Mammography status using 

patient self-reports and computerized 

radiology database. Am J Prev Med 

17(3): 203–6. 1999. 

27.	 May DS, Trontell AE. Mammography 

use by elderly women: A 

methodological comparison of two 

national data sources. Ann Epidemiol 

8(7): 439–44. 1998. 

28.	 Davidson JR, Meltzer-Brody SE. The 

underrecognition and undertreatment of 

depression: What is the breadth and 

depth of the problem? J Clin Psychiatry 

60 (Suppl 7): 4–9. 1999. 

29.	 Druss BG, Hoff RA, Rosenheck RA. 

Underuse of antidepressants in major 

depression: Prevalence and correlates in 

a national sample of young adults. J 

Clin Psychiatry 61(3): 234–7. 2000. 

30.	 Padgett DK. Women’s mental health: 

Some directions for research. Am J 

Orthopsychiatry 67(4): 522–34. 1997. 

31.	 Adams PF, Hendershot GE, Marano 

MA. Current estimates from the 

National Health Interview Survey, 

1996. National Center for Health 

Statistics. Vital Health Stat 10(200). 

1999. 

32.	 ‘‘Majority of Women Control Health 

Care Decisions,’’ based on a survey 

conducted by EDK Associates, Merck 

Media Minutes, Summer 1997. 

33.	 Stoverinck MJ, Lagro-Janssen AL, 

Weel CV. Sex differences in health 

problems, diagnostic testing, and 

referral in primary care. J Fam Practice 

43(6): 567–76. 1996. 

34.	 Verbrugge LM. The twain meet: 

Empirical explanations of sex 
Series 13, No. 149 

[ Page 17 

differences in health and mortality. 

J Health Soc Behav 30: 282–304. 1989. 

35. Macintyre S, Ford G, Hunt K. Do 

women ‘over-report’ morbidity? Men’s 

and women’s responses to structured 

prompting on a standard question on 

long standing illness. Soc Science Med 

48: 89–98. 1999. 
physician specialtiy and patient’s age and race for women 15 years of age and over: United States, average annual 1997–98 

All Outpatient Emergency All Outpatient Emergency 

pecialties Primary Surgical Nonsurgical department department specialties Primary Surgical Nonsurgical department department 

Number of visits in thousands Standard error 

Page 18 [ Series 13, No. 149 

499,785 257,572 81,870 80,951 37,753 41,640 14,828 10,665 4,288 4,090 2,926 1,508 

230,628 132,731 24,028 30,294 19,466 24,111 7,896 6,297 1,558 2,167 1,474 924 136,487 65,489 25,400 26,400 10,784 8,414 4,386 2,998 1,404 1,460 971 345 132,670 59,352 32,442 24,257 7,503 9,115 5,076 3,506 2,037 1,524 839 397 

419,240 216,909 73,523 69,759 27,256 31,792 14,332 10,033 4,103 3,625 2,439 1,419 

187,478 109,819 21,119 25,221 13,732 17,587 7,462 5,812 1,462 1,884 1,211 854 

114,875 55,466 22,588 22,733 7,680 6,409 4,187 2,851 1,324 1,291 763 312 

116,887 51,625 29,817 21,805 5,844 7,796 4,883 3,307 1,971 1,421 747 383 

62,489 30,393 5,916 7,917 9,342 8,920 4,001 3,422 553 1,079 850 434 

33,521 17,091 2,033 3,275 5,131 5,991 2,228 1,919 268 541 467 292 

16,533 7,177 2,053 2,766 2,760 1,776 1,096 853 232 433 361 115 12,435 6,124 1,830 1,876 1,452 1,153 1,369 1,226 236 350 167 92 

Percent distribution 

100.0 51.5 16.4 16.2 7.6 8.3 . . . 1.1 0.7 0.8 0.5 0.3 100.0 57.6 10.4 13.1 8.4 10.5 . . . 1.4 0.6 0.9 0.6 0.5 100.0 48.0 18.6 19.3 7.9 6.2 . . . 1.3 0.9 0.9 0.7 0.3 100.0 44.7 24.5 18.3 5.7 6.9 . . . 1.5 1.2 1.1 0.6 0.4 100.0 51.7 17.5 16.6 6.5 7.6 . . . 1.2 0.8 0.8 0.6 0.4 100.0 58.6 11.3 13.5 7.3 9.4 . . . 1.5 0.7 0.9 0.6 0.5 100.0 48.3 19.7 19.8 6.7 5.6 . . . 1.4 0.9 1.0 0.6 0.3 100.0 44.2 25.5 18.7 5.0 6.7 . . . 1.7 1.3 1.1 0.6 0.4 

100.0 48.6 9.5 12.7 15.0 14.3 . . . 2.9 0.9 1.7 1.4 0.9 100.0 51.0 6.1 9.8 15.3 17.9 . . . 2.8 0.9 1.6 1.5 1.1 100.0 43.4 12.4 16.7 16.7 10.7 . . . 3.5 1.4 2.4 2.1 0.7 100.0 49.3 14.7 15.1 11.7 9.3 . . . 5.1 1.9 3.0 1.7 1.0 

Number of visits per 100 women per year1 

459.9 237.2 75.0 74.6 34.9 38.2 13.6 9.8 3.9 3.8 2.7 1.4 380.1 218.8 39.6 49.9 32.1 39.7 13.0 10.4 2.6 3.6 2.4 1.5 473.5 227.2 88.1 91.6 37.4 29.2 15.2 10.4 4.9 5.0 3.4 1.9 

711.8 318.4 174.1 130.1 40.3 48.9 27.2 18.8 10.9 8.1 4.5 2.1 
physician specialtiy and patient’s age and race for women 15 years of age and over: United States, average annual 1997–98—Con. 

All Outpatient Emergency All Outpatient Emergency 

pecialties Primary Surgical Nonsurgical department department specialties Primary Surgical Nonsurgical department department 

Number of visits per 100 women per year1 Standard error 

461.9 240.4 79.5 76.5 30.3 35.2 15.8 11.1 4.4 4.0 2.7 1.6 

385.6 225.9 43.4 51.9 28.2 36.2 15.3 11.9 3.0 3.9 2.5 1.8 

472.0 227.9 92.8 93.4 31.6 26.3 17.2 11.7 5.4 5.3 3.1 1.3 707.6 312.5 180.5 132.0 35.4 47.2 29.6 20.0 11.9 8.6 4.5 2.3 

478.5 231.0 48.8 63.3 70.8 64.7 31.4 26.9 4.6 8.6 6.5 3.2 

380.7 194.1 23.1 37.2 58.3 68.0 25.3 21.8 3.0 6.1 5.3 3.3 

507.2 220.2 63.0 84.9 84.7 54.5 33.6 26.2 7.1 13.3 11.1 3.5 765.9 377.2 112.7 115.5 89.4 71.0 84.3 75.5 14.6 21.5 10.3 5.7 

tcensal estimates of the civilian noninstitutionalized population of the United States as of July 1, 1997, and July 1, 1998. Figures have been adjusted for net underenumeration using the 1990 National 

Series 13, No. 149 [ Page 19 
Page 20 [ Series 13, No. 149 

Table 2. Ambulatory care visits by detailed specialty of care and ambulatory care setting for women 15 years of age and over: 

United States, average annual 1997–98 

Percent 

distribution Rate per 

Number in Standard Percent Standard of visits to Standard 100 Standard 

Physician specialty thousands error distribution error care type error women1,2 error 

All visits ....................... 499,785 14,828 100.0 . . . . . . . . . 459.9 13.6 

Office-based visits ................. 420,393 13,039 84.1 0.7 100.0 . . . 386.8 12.0 

General and family practice ......... 103,561 6,515 20.7 1.2 24.6 1.3 95.5 6.0 

Internal medicine ................ 75,604 4,631 15.1 0.8 18.0 1.0 69.3 4.2 

Pediatrics .................... 3,476 469 0.7 0.1 0.8 0.1 3.2 0.4 

General surgery ................. 12,381 1,275 2.5 0.3 3.0 0.3 11.4 1.2 

Obstetrics and gynecology .......... 76,366 5,149 15.3 0.9 18.2 1.0 70.6 4.8 

Orthopedic surgery ............... 18,311 1,824 3.7 0.4 4.4 0.4 16.8 1.7 

Cardiovascular diseases ........... 8,756 908 1.8 0.2 2.1 0.2 7.9 0.8 

Dermatology ................... 16,725 1,456 3.4 0.3 4.0 0.3 15.4 1.3 

Urology ...................... 3,795 424 0.8 0.1 0.9 0.1 3.5 0.4 

Psychiatry .................... 12,590 1,266 2.5 0.2 3.0 0.3 11.8 1.2 

Neurology .................... 4,535 471 0.9 0.1 1.1 0.1 4.2 0.4 

Ophthalmology ................. 27,164 2,279 5.4 0.4 6.5 0.5 24.6 2.1 

Otolaryngology ................. 9,120 877 1.8 0.2 2.2 0.2 8.4 0.8 

All other ..................... 48,012 3,624 9.6 0.7 11.4 0.8 44.3 3.3 

Hospital outpatient visits ............. 37,753 2,890 7.6 0.5 100.0 . . . 34.9 2.7 

General medicine ................ 24,379 2,243 4.9 0.4 64.6 2.4 22.6 2.1 

Surgery ...................... 3,821 534 0.8 0.1 10.1 1.2 3.5 0.5 

Pediatrics .................... 814 139 0.2 0.0 2.2 0.4 0.7 0.1 

Obstetrics and gynecology .......... 6,000 705 1.2 0.1 15.9 1.6 5.5 0.6 

All other ..................... 2,739 459 0.6 0.1 7.3 1.2 2.5 0.4 

Emergency department visits .......... 41,640 1,272 8.3 0.3 100.0 . . . 38.2 1.2 

Emergent ..................... 8,832 533 1.8 0.1 21.2 1.2 8.1 0.5 

Urgent ...................... 13,419 681 2.7 0.2 32.2 1.2 12.3 0.6 

Semiurgent ................... 5,784 399 1.2 0.1 13.9 0.8 5.3 0.4 

Nonurgent .................... 3,585 325 0.7 0.1 8.6 0.7 3.3 0.3 

No triage/unknown ............... 10,019 819 2.0 0.2 24.1 1.9 9.2 0.8 

. . . 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, 1997, and July 1, 1998. Figures have been adjusted 

for net underenumeration using the 1990 National Population Adjustment Matrix. 

2Age-adjusted. 
ffice-based physicians and hospital outpatient departments by type of provider seen, according to age and race for women 15 years of age and 

 1997–98 

Age Race Age Race 

All visits 

15–44 

years 

45–64 

years 

65 years


and over White Black
 All visits 

15–44 

years 

45–64 

years 

65 years


and over White Black


Number of visits in thousands Standard error 

458,146 206,518 128,074 123,554 387,447 53,568 14,469 7,707 4,301 5,003 13,924 3,917 

434,211 193,898 121,880 118,433 367,689 49,959 13,596 7,141 4,076 4,814 13,097 3,683 

6,505 4,212 1,435 858 5,089 1,309 1,228 909 321 209 1,015 366 

*1,076 *848 * * *880 154 340 289 . . . . . . 313 38 

75,819 35,058 22,555 18,206 62,849 10,604 5,553 2,935 1,963 1,673 4,899 1,398 52,385 25,843 13,279 13,263 45,050 5,988 5,865 3,454 1,631 1,608 5,576 1,101 

05,035 47,530 29,153 28,352 89,296 12,164 6,824 3,880 2,160 2,011 6,159 1,827 

10,177 3,819 2,792 3,565 8,457 *1,531 1,507 553 543 632 1,306 550 

3,267 1,423 761 1,083 2,736 454 521 261 136 240 499 128 

28,007 11,809 8,069 8,129 23,230 3,434 3,092 1,593 1,047 1,187 2,720 488 

Percent distribution 

100.0 100.0 100.0 100.0 100.0 100.0 . . . . . . . . . . . . . . . . . . 

94.8 93.9 95.2 95.9 94.9 93.3 0.4 0.5 0.4 0.6 0.4 0.9 

1.4 2.0 1.1 0.7 1.3 2.4 0.3 0.4 0.2 0.2 0.3 0.7 

*0.2 *0.4 * * *0.2 0.3 0.1 0.1 . . . . . . 0.1 0.1 

16.6 17.0 17.6 14.7 16.2 19.8 1.2 1.3 1.4 1.3 1.2 2.0 

11.4 12.5 10.4 10.7 11.6 11.2 1.2 1.5 1.2 1.2 1.3 1.7 

22.9 23.0 22.8 23.0 23.1 22.7 1.4 1.8 1.5 1.4 1.4 2.5 

2.2 1.9 2.2 2.9 2.2 *2.9 0.3 0.3 0.4 0.5 0.3 1.0 

0.7 0.7 0.6 0.9 0.7 0.9 0.1 0.1 0.1 0.2 0.1 0.2 

6.1 5.7 6.3 6.6 6.0 6.4 0.7 0.8 0.8 0.9 0.7 1.0 

Number of visits per 100 women1 

2421.7 340.4 444.3 662.9 2426.7 2413.8 13.3 12.7 14.9 26.8 15.3 30.1 2399.6 319.6 422.8 635.4 2404.7 2387.3 12.5 11.8 14.1 25.8 14.4 29.1 

26.0 6.9 5.0 4.6 25.7 29.0 1.1 1.5 1.1 1.1 1.1 2.4 

*21.0 *1.4 * * *21.0 21.0 0.3 0.5 . . . . . . 0.4 0.2 

270.0 57.8 78.2 97.7 269.6 282.1 5.1 4.8 6.8 9.0 5.4 11.2 248.2 42.6 46.1 71.2 249.8 247.6 5.4 5.7 5.7 8.6 6.2 9.4 296.7 78.3 101.1 152.1 298.3 293.2 6.3 6.4 7.5 10.8 6.8 14.2 

29.3 6.3 9.7 19.1 29.2 *211.9 1.4 0.9 1.9 3.4 1.4 4.4 23.0 2.3 2.6 5.8 23.0 23.5 0.5 0.4 0.5 1.3 0.5 1.0 

225.8 19.5 28.0 43.6 225.5 226.2 2.8 2.6 3.6 6.4 3.0 3.7 

cision. 

tcensal estimates of the civilian noninstitutionalized population of the United States as of July 1, 1997, and July 1, 1998. Figures have been adjusted for net underenumeration using the 1990 National 

Series 13, No. 149 [ Page 21 
nt for ambulatory care visits by age and race for women 15 years of age and over: United States, average annual 1997–98 

Age Race Age Race 

15–44 45–64 65 years 15–44 45–64 65 years 

All visits years years and over White Black All visits years years and over White Black 

Number of visits in thousands Standard error 

499,785 230,628 136,487 132,670 419,240 62,489 14,828 7,896 4,386 5,076 14,332 4,001 

249,661 142,073 87,218 20,370 215,302 24,876 8,525 5,697 3,012 1,311 8,451 1,753 

111,240 4,769 9,973 96,498 98,374 10,369 4,391 395 700 4,024 4,149 1,126 

47,160 30,643 10,655 5,862 30,409 14,052 2,535 1,772 714 676 1,953 1,374 

21,401 12,287 6,321 2,792 17,213 3,186 2,316 1,391 782 618 1,944 708 

40,784 25,769 12,512 2,503 34,277 5,351 2,276 1,506 836 455 2,087 547 

6,738 3,285 2,074 1,379 5,243 *1,349 1,294 821 513 253 981 552 

9,663 5,259 3,880 525 7,560 1,350 1,233 763 559 105 1,120 237 

13,139 6,545 3,855 2,740 10,861 1,956 1,040 594 339 377 913 231 

Percent distribution 

Page 22 [ Series 13, No. 149 

100.0 100.0 100.0 100.0 100.0 100.0 . . . . . . . . . . . . . . . . . . 

50.0 61.6 63.9 15.4 51.4 39.8 0.8 1.1 1.0 0.9 0.9 1.8 

22.3 2.1 7.3 72.7 23.5 16.6 0.6 0.2 0.4 1.0 0.5 1.3 

9.4 13.3 7.8 4.4 7.3 22.5 0.5 0.7 0.5 0.5 0.4 1.4 

4.3 5.3 4.6 2.1 4.1 5.1 0.4 0.6 0.5 0.5 0.4 1.1 

8.2 11.2 9.2 1.9 8.2 8.6 0.4 0.5 0.5 0.3 0.4 0.7 

1.4 1.4 1.5 1.0 1.3 *2.2 0.3 0.3 0.4 0.2 0.2 0.9 

1.9 2.3 2.8 0.4 1.8 2.2 0.2 0.3 0.4 0.1 0.3 0.4 

2.6 2.8 2.8 2.1 2.6 3.1 0.2 0.2 0.2 0.3 0.2 0.4 

Number of visits per 100 women per year1 

2459.9 380.1 473.5 711.8 2461.9 2478.5 13.6 13.0 15.2 27.2 15.8 31.4 2233.4 234.2 302.6 109.3 2244.6 2182.0 7.9 9.4 10.4 7.0 9.6 12.8 

297.5 7.9 34.6 517.8 298.0 297.6 3.8 0.7 2.4 21.6 4.1 10.7 243.6 50.5 37.0 31.5 234.3 2101.5 2.3 2.9 2.5 3.6 2.2 10.4 219.9 20.3 21.9 15.0 219.4 224.0 2.1 2.3 2.7 3.3 2.2 5.4 238.1 42.5 43.4 13.4 239.0 237.9 2.1 2.5 2.9 2.4 2.4 3.8 

26.2 5.4 7.2 7.4 25.8 2*10.3 1.2 1.4 1.8 1.4 1.1 4.2 29.1 8.7 13.5 2.8 28.6 210.1 1.2 1.3 1.9 0.6 1.3 1.8 

212.1 10.8 13.4 14.7 212.1 215.2 1.0 1.0 1.2 2.0 1.0 1.9 

cision. 

tcensal estimates of the civilian noninstitutionalized population of the United States as of July 1, 1997, and July 1, 1998. Figures have been adjusted for net underenumeration using the 1990 National 
ffice-based physicians and hospital outpatient departments by major reason for visit, age, and race for women 15 years of age and over: 

–98 

All Acute Chronic Pre/post Non- All Acute Chronic Pre/post Non

visits condition condition surgery illness Unknown visits condition condition surgery illness Unknown 

Number of visits in thousands Standard error 

458,146 141,270 176,854 36,967 94,258 8,797 14,469 5,485 6,062 1,970 4,975 905 

206,518 68,526 56,411 13,319 64,620 3,643 7,707 2,893 2,397 950 4,000 416 

28,074 39,802 57,610 10,644 17,694 2,323 4,301 1,761 2,201 685 1,195 310 23,554 32,942 62,833 13,004 11,945 2,831 5,003 1,816 2,748 809 847 402 

387,447 120,453 148,194 32,378 78,748 7,675 13,924 5,149 5,664 1,871 4,674 854 

69,891 56,760 45,905 11,076 52,962 3,188 7,243 2,711 2,172 860 3,670 395 

08,466 34,244 47,501 9,408 15,266 2,046 4,102 1,669 1,998 662 1,141 281 09,091 29,448 54,789 11,893 10,520 2,440 4,798 1,691 2,626 788 847 363 

53,568 15,269 22,062 3,565 11,862 811 3,817 1,468 1,944 384 1,027 145 

27,530 8,699 7,844 1,722 8,960 305 2,108 938 705 244 942 81 

14,756 3,942 7,913 877 1,788 *235 1,047 373 748 156 219 77 

11,282 2,629 6,304 965 1,113 *271 1,340 467 821 165 269 87 

Percent distribution 

100.0 30.8 38.6 8.1 20.6 1.9 . . . 0.7 0.8 0.3 0.8 0.2 

100.0 33.2 27.3 6.5 31.3 1.8 . . . 1.0 0.9 0.4 1.2 0.2 

100.0 31.1 45.0 8.3 13.8 1.8 . . . 0.8 1.0 0.5 0.8 0.2 100.0 26.7 50.9 10.5 9.7 2.3 . . . 0.9 0.9 0.5 0.6 0.3 100.0 31.1 38.3 8.4 20.3 2.0 . . . 0.7 0.8 0.4 0.8 0.2 

100.0 33.4 27.0 6.5 31.2 1.9 . . . 1.1 0.9 0.4 1.3 0.2 

100.0 31.6 43.8 8.7 14.1 1.9 . . . 0.9 1.1 0.5 0.9 0.3 100.0 27.0 50.2 10.9 9.6 2.2 . . . 0.9 1.0 0.6 0.6 0.3 

100.0 28.5 41.2 6.7 22.1 1.5 . . . 1.5 1.6 0.7 1.6 0.3 

100.0 31.6 28.5 6.3 32.6 1.1 . . . 2.2 1.6 0.8 2.3 0.3 

100.0 26.7 53.6 6.0 12.1 *1.6 . . . 2.0 2.5 1.0 1.3 0.5 100.0 23.3 55.9 8.6 9.9 *2.4 . . . 2.4 2.4 1.5 2.1 0.8 

Number of visits per 100 women per year1 

421.7 130.3 162.5 33.9 86.9 8.1 13.3 5.0 5.6 1.8 4.6 0.8 

340.4 112.9 93.0 22.0 106.5 6.0 12.7 4.8 3.9 1.6 6.6 0.7 

444.3 138.1 199.8 36.9 61.4 8.1 14.9 6.1 7.6 2.4 4.1 1.1 662.9 176.7 337.1 69.8 64.1 15.2 26.8 9.7 14.7 4.3 4.5 2.2 

Series 13, No. 149 [ Page 23 
ffice-based physicians and hospital outpatient departments by major reason for visit, age, and race for women 15 years of age and over: 

–98—Con. 

All Acute Chronic Pre/post Non- All Acute Chronic Pre/post Non

visits condition condition surgery illness Unknown visits condition condition surgery illness Unknown 

Page 24 [ Series 13, No. 149 Number of visits per 100 women per year1 Standard error 

426.7 133.4 161.1 35.2 88.6 8.4 15.3 5.7 6.1 2.1 5.3 0.9 

349.4 116.7 94.4 22.8 108.9 6.6 14.9 5.6 4.5 1.8 7.5 0.8 

445.7 140.7 195.2 38.7 62.7 8.4 16.8 6.8 8.2 2.7 4.7 1.2 660.4 178.3 331.7 72.0 63.7 14.8 29.0 10.2 15.9 4.8 5.1 2.2 

413.8 115.2 180.7 28.1 83.2 6.7 30.1 11.2 16.3 3.0 6.9 1.2 

312.7 98.8 89.1 19.6 101.8 3.5 23.9 10.7 8.0 2.8 10.7 0.9 

452.7 120.9 242.8 26.9 54.9 7.2 32.1 11.4 22.9 4.8 6.7 2.4 694.9 161.9 388.3 59.5 68.6 16.7 82.5 28.8 50.6 10.1 16.6 5.3 

cision. 

tcensal estimates of the civilian noninstitutionalized population of the United States as of July 1, 1997, and July 1, 1998. Figures have been adjusted for net underenumeration using the 1990 National 
Series 13, No. 149 [ Page 25 

Table 6. Ambulatory care visits for the 10 principal reasons for visit most frequently mentioned by age and race for women 15 years of age 

and over: United States, annual average 1997–98 

Number in Standard Percent Standard Rate per Standard 

Principal reason for visit and RVC code1 thousands error distribution error 100 women2 error 

All visits 

General medical examination ....................... 3100 34,277 2,425 6.9 0.4 3

31.6 2.2 

Prenatal examination, routine ....................... 3205 28,793 2,539 5.8 0.5 3

26.4 2.3 

Progress visit not otherwise specified .................. 4800 18,059 1,565 3.6 0.3 3

16.5 1.4 

Stomach and abdominal pain, cramps, and spasms ......... 1545 12,120 623 2.4 0.1 3

11.2 0.6 

Postoperative visit .............................. 4205 11,165 837 2.2 0.1 3

10.3 0.8 

Cough ..................................... 1440 10,558 681 2.1 0.2 3

9.7 0.6 

Vision dysfunctions ............................. 1305 8,632 838 1.7 0.1 3

7.8 0.8 

Headache, pain in head .......................... 1210 8,388 531 1.7 0.1 3

7.8 0.5 

Symptoms referable to throat ....................... 1455 8,047 522 1.6 0.1 3

7.4 0.5 

Back symptoms ............................... 1905 7,996 580 1.6 0.1 3

7.4 0.5 

All other reasons .................................. 351,751 10,588 70.4 0.6 3

323.8 9.7 

Age 

15–44 years: 

Prenatal examination, routine ..................... 3205 28,755 2,538 12.5 0.9 47.4 4.2 

General medical examination ..................... 3100 15,308 1,456 6.6 0.5 25.2 2.4 

Stomach and abdominal pain, cramps, and spasms ....... 1545 6,524 379 2.8 0.2 10.8 0.6 

Symptoms referable to throat ..................... 1455 5,587 417 2.4 0.2 9.2 0.7 

Progress visit not otherwise specified ................ 4800 5,485 518 2.4 0.2 9.0 0.9 

Headache, pain in head ......................... 1210 5,023 385 2.2 0.2 8.3 0.6 

Cough .................................... 1440 4,466 366 1.9 0.1 7.4 0.6 

Depression ................................. 1110 3,910 445 1.7 0.2 6.4 0.7 

Postoperative visit ............................ 4205 3,890 414 1.7 0.2 6.4 0.7 

Back symptoms .............................. 1905 3,586 342 1.6 0.2 5.9 0.6 

All other reasons ................................. 148,097 4,837 64.2 0.7 244.1 8.0 

45–64 years: 

General medical examination ..................... 3100 10,220 835 7.5 0.5 35.5 2.9 

Progress visit not otherwise specified ................ 4800 5,449 599 4.0 0.4 18.9 2.1 

Postoperative visit ............................ 4205 3,422 339 2.5 0.2 11.9 1.2 

Stomach and abdominal pain, cramps, and spasms ....... 1545 3,216 290 2.4 0.2 11.2 1.0 

Cough .................................... 1440 3,058 322 2.2 0.2 10.6 1.1 

Hypertension ............................... 2510 2,952 388 2.2 0.3 10.2 1.4 

Depression ................................. 1110 2,647 315 1.9 0.2 9.2 1.1 

Back symptoms .............................. 1905 2,593 235 1.9 0.2 9.0 0.8 

Knee symptoms .............................. 1925 2,460 255 1.8 0.2 8.5 0.9 

Chest pain and related symptoms .................. 1050 2,344 240 1.7 0.2 8.1 0.8 

All other reasons ................................. 98,126 3,169 71.9 0.8 340.4 11.0 

65 years and over: 

General medical examination ..................... 3100 8,749 828 6.6 0.6 46.9 4.4 

Progress visit not otherwise specified ................ 4800 7,125 689 5.4 0.5 38.2 3.7 

Vision dysfunctions ............................ 1305 4,737 495 3.6 0.4 25.4 2.7 

Postoperative visit ............................ 4205 3,853 373 2.9 0.3 20.7 2.0 

Cough .................................... 1440 3,035 314 2.3 0.2 16.3 1.7 

Hypertension ............................... 2510 2,814 321 2.1 0.2 15.1 1.7 

Chest pain and related symptoms .................. 1050 2,791 288 2.1 0.2 15.0 1.6 

Blood pressure test ........................... 3320 2,603 363 2.0 0.3 14.0 2.0 

Stomach and abdominal pain, cramps, and spasms ....... 1545 2,380 265 1.8 0.2 12.8 1.4 

Knee symptoms .............................. 1925 2,257 321 1.7 0.2 12.1 1.7 

All other reasons ................................. 92,325 3,601 69.6 0.8 495.4 19.3 

Race 

White: 

General medical examination ..................... 3100 28,740 2,148 6.9 0.4 3

31.8 2.4 

Prenatal examination, routine ..................... 3205 23,469 2,367 5.6 0.5 3

26.9 2.7 

Progress visit not otherwise specified ................ 4800 14,591 1,442 3.5 0.3 3

15.7 1.6 

Postoperative visit ............................ 4205 9,935 819 2.4 0.2 3

10.8 0.9 

Stomach and abdominal pain, cramps, and spasms ....... 1545 9,263 556 2.2 0.1 3

10.3 0.6 

Cough .................................... 1440 9,166 662 2.2 0.1 3

10.1 0.7 

Vision dysfunctions ............................ 1305 7,893 824 1.9 0.2 3

8.3 0.9 

Symptoms referable to throat ..................... 1455 7,037 497 1.7 0.1 3

7.9 0.6 

Headache, pain in head ......................... 1210 6,748 465 1.6 0.1 3

7.6 0.5 

Back symptoms .............................. 1905 6,686 488 1.6 0.1 3

7.4 0.5 

All other reasons ................................. 295,712 10,146 70.5 0.7 3

325.1 11.1 

See footnotes at end of table. 
Page 26 [ Series 13, No. 149 

Table 6. Ambulatory care visits for the 10 principal reasons for visit most frequently mentioned by age and race for women 15 years of age 

and over: United States, annual average 1997–98—Con. 

Number in Standard Percent Standard Rate per Standard 

Principal reason for visit and RVC code1 thousands error distribution error 100 women2 error 

Race—Continued 

Black: 

General medical examination ..................... 3100 4,653 598 7.5 0.8 3

36.8 5.2 

Prenatal examination, routine ..................... 3205 3,855 627 6.2 0.9 3

24.4 4.0 

Progress visit not otherwise specified ................ 4800 3,067 363 4.9 0.6 3

25.4 3.1 

Stomach and abdominal pain, cramps, and spasms ....... 1545 2,104 205 3.4 0.3 3

15.2 1.6 

Chest pain and related symptoms .................. 1050 1,431 202 2.3 0.3 3

11.7 1.7 

Hypertension ............................... 2510 1,276 272 2.0 0.4 3

10.8 2.3 

Headache, pain in head ......................... 1210 1,154 161 1.9 0.3 3

8.2 1.1 

Knee symptoms .............................. 1925 1,033 236 1.7 0.4 3

8.5 1.9 

Postoperative visit ............................ 4205 980 173 1.6 0.3 3

7.9 1.5 

Medication, other and unspecified kinds ............... 4115 968 283 1.6 0.4 3

7.7 2.2 

All other reasons ................................. 41,969 2,859 67.2 1.4 3

321.9 22.3 

1Based on A Reason for Visit Classification for Ambulatory Care (RVC) (16). 

2Based on U.S. Bureau of the Census monthly postcensal estimates of the civilian noninstitutionalized population of the United States as of July 1, 1997, and July 1, 1998. Figures have been adjusted 

for net underenumetation using the 1990 National Population Adjustment Matrix. 

3Age-adjusted. 
Series 13, No. 149 [ Page 27 

Table 7. Ambulatory care visits for the 10 diagnosis groups most frequently mentioned by age and race for women 15 years of age and 

over: United States, average annual 1997–98 

Number in Standard Percent Standard Rate per Standard 

Primary diagnosis group and ICD–9–CM Code(s)1 thousands error distribution error 100 women2 error 

All visits 

Normal pregnancy ............................ V22 29,900 2,484 6.0 0.4 3

27.4 2.3 

Essential hypertension .......................... 401 19,420 1,251 3.9 0.2 3

17.7 1.2 

Arthropathies and related disorders .............. 710–719 15,279 1,391 3.1 0.3 3

14.1 1.3 

Acute URI4 

, excluding pharyngitis ......... 460–461, 463–466 12,661 890 2.5 0.2 311.7 0.8 

General medical examination ..................... V70 11,533 1,002 2.3 0.2 3

10.7 0.9 

Rheumatism, excluding back .................. 725–729 11,317 674 2.3 0.1 3

10.5 0.6 

Diabetes ................................... 250 11,289 812 2.3 0.2 3

10.4 0.8 

Dorsopathies ............................ 720–724 10,439 926 2.1 0.2 3

9.7 0.9 

Malignant neoplasm ................. 140–208, 230–234 9,279 1,118 1.9 0.2 3

8.5 1.0 

Gynecological examination ..................... V72.3 8,630 957 1.7 0.2 3

8.0 0.9 

All other diagnoses .............................. 360,039 10,705 72.0 0.6 3

331.3 9.8 

Age 

15–44 years: 

Normal pregnancy .......................... V22 29,864 2,484 13.0 0.8 49.2 4.1 

Acute URI,4 excluding pharyngitis ........ 460–461, 463–466 7,368 600 3.2 0.2 12.1 1.0 

General medical examination ................... V70 7,157 660 3.1 0.3 11.8 1.1 

Complications of pregnancy, childbirth ........... 630–677 6,734 645 2.9 0.3 11.1 1.1 

Gynecological examination .................... V72.3 5,768 722 2.5 0.3 9.5 1.2 

Dorsopathies .......................... 720–724 4,603 635 2.0 0.3 7.6 1.1 

Rheumatism, excluding back ................. 725–729 4,228 359 1.8 0.2 7.0 0.6 

Chronic sinusitis ............................ 473 4,041 386 1.8 0.2 6.7 0.6 

Inflammatory disorders of female pelvic organs ..... 614–616 3,665 441 1.6 0.2 6.0 0.7 

Disorders of menstruation and abnormal bleeding ........ 626 3,563 389 1.5 0.2 5.9 0.6 

All other diagnoses ............................. 153,637 5,006 66.6 1.0 253.2 8.2 

45–64 years: 

Essential hypertension ........................ 401 7,235 629 5.3 0.4 25.1 2.2 

Arthropathies and related disorders ............. 710–719 5,970 636 4.4 0.4 20.7 2.2 

Diabetes ................................. 250 4,854 450 3.6 0.3 16.8 1.6 

Rheumatism, excluding back ................. 725–729 4,285 357 3.1 0.3 14.9 1.2 

Dorsopathies .......................... 720–724 3,577 387 2.6 0.3 12.4 1.3 

Malignant neoplasm ................ 140–208, 230–234 3,199 483 2.3 0.4 11.1 1.7 

Acute URI,4 excluding pharyngitis ........ 460–461, 463–466 3,044 354 2.2 0.3 10.6 1.2 

General medical examination ................... V70 2,926 353 2.1 0.3 10.2 1.2 

Menopausal and postmenopausal disorders ........... 627 2,917 378 2.1 0.3 10.1 1.3 

Gynecological examination .................... V72.3 2,311 336 1.7 0.2 8.0 1.2 

All other diagnoses ............................. 96,170 3,138 70.5 0.9 333.6 10.9 

65 years and over: 

Essential hypertension ........................ 401 10,331 785 7.8 0.5 55.4 4.2 

Arthropathies and related disorders ............. 710–719 6,340 688 4.8 0.5 34.0 3.7 

Cataract ................................. 366 5,611 608 4.2 0.4 30.1 3.3 

Malignant neoplasm ................ 140–208, 230–234 4,799 539 3.6 0.4 25.8 2.9 

Diabetes ................................. 250 4,683 416 3.5 0.3 25.1 2.2 

Heart disease, excluding ischemic ...... 391–392.0, 393–398, 

402, 404, 415–416, 420–429 4,423 427 3.3 0.3 23.7 2.3 

Ischemic heart disease .................... 410–414 4,204 530 3.2 0.4 22.6 2.8 

Glaucoma ................................ 365 3,059 398 2.3 0.3 16.4 2.1 

Rheumatism, excluding back ................. 725–729 2,803 326 2.1 0.2 15.0 1.8 

Dorsopathies .......................... 720–724 2,260 280 1.7 0.2 12.1 1.5 

All other diagnoses ............................. 84,157 3,129 63.4 0.8 451.5 16.8 

Race 

White: 

Normal pregnancy .......................... V22 24,766 2,334 5.9 0.5 3

28.3 2.7 

Essential hypertension ........................ 401 15,148 1,122 3.6 0.2 3

15.9 1.2 

Arthropathies and related disorders ............. 710–719 12,214 1,222 2.9 0.3 3

13.2 1.3 

Acute URI,4 excluding pharyngitis ........ 460–461, 463–466 10,524 790 2.5 0.2 3

11.8 0.9 

Rheumatism, excluding back ................. 725–729 9,581 668 2.3 0.2 3

10.6 0.7 

General medical examination ................... V70 9,537 844 2.3 0.2 3

10.8 1.0 

Dorsopathies .......................... 720–724 8,792 702 2.1 0.2 3

9.8 0.8 

Diabetes ................................. 250 8,534 695 2.0 0.2 3

9.2 0.8 

Malignant neoplasm ................ 140–208, 230–234 8,439 987 2.0 0.2 3

8.6 1.1 

Gynecological examination .................... V72.3 8,116 1,009 1.9 0.2 3

8.5 1.0 

All other diagnoses ............................. 304,544 10,455 72.6 0.7 3

335.2 11.5 

See footnotes at end of table. 
Page 28 [ Series 13, No. 149 

Table 7. Ambulatory care visits for the 10 diagnosis groups most frequently mentioned by age and race for women 15 years of age and 

over: United States, average annual 1997–98—Con. 

Number in Standard Percent Standard Rate per Standard 

Primary diagnosis group and ICD–9–CM Code(s)1 thousands error distribution error 100 women2 error 

Race—Continued 

Black: 

Normal pregnancy .......................... V22 3,773 525 6.0 0.8 3

23.9 3.3 

Essential hypertension ........................ 401 3,437 474 5.5 0.6 3

29.4 4.1 

Diabetes ................................. 250 2,524 367 4.0 0.5 3

21.9 3.2 

Arthropathies and related disorders ............. 710–719 2,340 363 3.7 0.5 3

19.8 3.2 

General medical examination ................... V70 1,553 256 2.5 0.4 3

11.5 2.0 

Complications of pregnancy, childbirth ........... 620–709 1,546 291 2.5 0.4 3

9.8 1.8 

Acute URI,4 excluding pharyngitis ........ 460–461, 463–466 1,469 238 2.4 0.3 3

11.1 1.9 

Rheumatism, excluding back ................. 725–729 1,319 264 2.1 0.4 3

10.3 2.0 

Inflammatory disorders of female pelvic organs ..... 614–616 1,147 206 1.8 0.3 3

7.6 1.4 

Benign neoplasm .................. 210–229, 235–239 1,088 181 1.7 0.3 3

8.8 2.6 

All other diagnoses ............................. 42,293 2,543 67.7 1.2 3

325.1 20.0 

1These groups are based on the International Classification of Diseases, 9th Revision, Clinical Modification (ICD–9–CM). However, certain codes have been combined in this table to form larger 

categories that better describe the utilization of ambulatory care services. 

2Based on U.S. Bureau of the Census monthly postcensal estimates of the civilian noninstitutionalized population of the United States as of July 1, 1997, and July 1, 1998. Figures have been adjusted 

for net underenumeration using the 1990 National Population Adjustment Matrix. 

3Age-adjusted. 

4URI is upper respiratory infection. 

Table 8. Injury-related ambulatory care visits by age and race for women 15 years of age and over: United States, average annual 1997–98 

Percent Percent 

Number in Standard distribution Standard distribution of Standard Rate per Standard 

Characteristic thousands error of all visits error injury visits error 100 women1 error 

All injury visits ..................... 54,611 2,145 10.9 0.3 100.0 . . . 2

50.3 2.0 

Age 

15–44 years ...................... 27,929 1,275 12.1 0.5 51.1 1.1 46.0 2.1 

45–64 years ...................... 14,373 636 10.5 0.4 26.3 0.8 49.9 2.2 

65 years and over ................... 12,309 782 9.3 0.5 22.5 1.0 66.0 4.2 

Age and race 

White 45,432 1,913 10.8 0.3 100.0 . . . 2

50.3 2.1 

15–44 years ..................... 22,351 1,082 11.9 0.5 49.2 1.2 46.0 2.2 

45–64 years ..................... 12,047 599 10.5 0.4 26.5 0.9 49.5 2.5 

65 years and over ................. 11,034 753 9.4 0.5 24.3 1.2 66.8 4.6 

Black ........................... 6,696 497 10.7 0.6 100.0 . . . 2

49.6 3.7 

15–44 years ..................... 4,086 351 12.2 0.9 61.0 2.5 46.4 4.0 

45–64 years ..................... 1,657 184 10.0 1.0 24.8 2.0 50.9 5.6 

65 years and over ................. 952 143 7.7 1.2 14.2 1.9 58.7 8.8 

. . . 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, 1997, and July 1, 1998. Figures have been adjusted 

for net underenumeration using the 1990 National Population Adjustment Matrix. 

2Age-adjusted. 
Series 13, No. 149 [ Page 29 

Table 9. Ambulatory care visits by place of occurrence, whether injury was work related, intent, and mechanism for women 15 years of age 

and over: United States, average annual 1997–98 

Rate 

Number in Standard Percent Standard per 100 Standard 

Characteristic thousands error distribution error women1 error 

All injury-related visits ............................ 54,611 2,145 100.0 . . . 50.3 2.0 

Place of occurrence 

Home ...................................... 10,626 586 19.5 0.8 9.7 0.5 

Recreation/sports area ............................ 2,027 227 3.7 0.4 1.9 0.2 

Street or highway ............................... 6,645 666 12.2 1.1 6.2 0.6 

Other public place ............................... 2,408 252 4.4 0.4 2.2 0.2 

Industrial places ................................ 3,649 406 6.7 0.7 3.4 0.4 

Other and unknown2 ............................. 29,256 1,376 53.6 1.4 27.0 1.3 

Work related 

Yes ........................................ 8,281 699 15.2 1.0 7.7 0.7 

No ........................................ 21,963 1,152 40.2 1.4 20.2 1.1 

Unknown/blank ................................ 24,367 1,093 44.6 1.4 22.4 1.0 

Intent 

Yes (self-inflicted) ............................... 497 85 0.9 0.2 0.5 0.1 

Yes (assault) .................................. 1,283 160 2.4 0.3 1.2 0.2 

No (unintentional) ............................... 37,995 1,624 69.6 1.2 35.0 1.5 

Unknown/blank ................................ 14,837 844 27.2 1.1 13.7 0.8 

Mechanism 

Falls ....................................... 9,385 541 17.2 0.9 8.6 0.5 

Motor vehicle traffic .............................. 6,102 652 11.2 1.1 5.7 0.6 

Struck against or struck accidentally by objects or persons ..... 3,737 294 6.8 0.5 3.5 0.3 

Overexertion .................................. 3,682 412 6.7 0.7 3.4 0.4 

Natural and environmental factors ..................... 1,842 205 3.4 0.4 1.7 0.2 

Cutting or piercing ............................... 1,509 154 2.8 0.3 1.4 0.1 

Poisonings ................................... 1,134 163 2.1 0.3 1.0 0.1 

Other and not elsewhere classified .................... 8,217 517 15.1 0.8 7.6 0.5 

Not specified .................................. 5,044 429 9.2 0.7 4.7 0.4 

Blank ....................................... 13,959 882 25.6 1.1 12.9 0.8 

. . . 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, 1997, and July 1, 1998. Figures have been adjusted 

for net underenumeration using the 1990 National Population Adjustment Matrix. Rates are age-adjusted. 

2‘‘Other’’ and ‘‘unknown’’ were combined because of a processing error in 1997. 
Page 30 [ Series 13, No. 149 

Table 10. Visits to office-based physicians and hospital outpatient departments for selected diagnostic and screening services ordered or 

provided, by age and race for women 15 years of age and over: United States, average annual 1997–98 

Age Race Age Race 

Diagnostic and screening All 15–44 45–64 65 years All 15–44 45–64 65 years 

services ordered or provided visits years years and over White Black visits years years and over White Black 

Number of visits in thousands Standard error 

All visits ................ 458,146 206,518 128,074 123,554 387,447 53,568 14,469 7,707 4,301 5,003 13,924 3,817 

No services .............. 93,403 43,829 27,845 21,728 81,870 8,778 4,805 2,452 1,609 1,519 4,564 797 

Examinations 

Breast ................. 50,816 27,112 14,952 8,751 42,288 6,043 2,671 1,825 950 692 2,381 642 

Pelvic ................. 62,753 41,416 14,867 6,471 52,227 8,124 3,817 2,999 1,063 584 3,486 843 

Rectal ................. 21,479 9,061 7,477 4,941 18,291 2,010 1,417 861 601 461 1,264 332 

Skin .................. 38,939 17,212 11,620 10,107 33,502 4,100 2,655 1,341 889 1,023 2,368 576 

Vision ................. 30,335 7,031 7,893 15,411 25,814 3,061 2,452 628 724 1,503 2,209 400 

Glaucoma ............... 19,151 2,806 5,347 10,999 16,177 1,925 1,776 361 598 1,105 1,622 330 

Hearing ................ 5,173 2,131 1,498 1,544 3,752 640 774 355 229 370 386 132 

Tests 

Blood pressure ............ 256,621 118,906 70,203 67,512 213,942 32,851 9,973 5,668 2,955 3,422 9,098 3,322 

Hemoglobin .............. 25,999 10,919 7,930 7,149 21,167 3,526 1,752 942 642 693 1,612 439 

Pap ................... 38,126 23,264 10,913 3,948 32,327 4,497 2,595 1,814 921 412 2,374 457 

Urinalysis ............... 61,994 40,463 11,618 9,913 50,340 9,065 3,841 3,122 866 822 3,457 1,075 

Pregnancy test ............ 5,699 5,478 * 0 4,168 1,211 567 554 . . . . . . 432 228 

Cholesterol measure ........ 16,618 4,306 6,054 6,259 13,482 2,201 1,110 455 525 624 984 317 

HIV serology ............. 1,971 1,650 *200 * 1,384 353 299 269 77 . . . 246 70 

Other STD1 test ........... 3,942 3,228 *435 * 2,613 1,036 595 472 143 . . . 483 183 

Imaging 

EKG1 ................. 11,936 2,412 3,531 5,993 9,951 1,692 912 252 376 574 848 230 

Mammography ............ 15,575 4,162 7,819 3,594 13,059 2,067 1,151 428 658 398 985 329 

Ultrasound .............. 16,760 10,841 3,204 2,715 13,162 2,277 1,463 1,215 370 320 1,170 318 

CAT scan/MRI1 ........... 4,940 1,962 1,554 1,424 4,173 615 356 208 207 187 315 110 

X ray .................. 26,592 9,170 8,147 9,275 22,517 3,339 1,407 575 579 701 1,340 339 

Percent distribution 

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

No services .............. 20.4 21.2 21.7 17.6 21.1 16.4 0.8 0.9 1.0 1.0 0.9 1.3 

Exams 

Breast ................. 11.1 13.1 11.7 7.1 10.9 11.3 0.5 0.7 0.7 0.5 0.5 0.9 

Pelvic ................. 13.7 20.1 11.6 5.2 13.5 15.2 0.7 1.0 0.8 0.4 0.7 1.3 

Rectal ................. 4.7 4.4 5.8 4.0 4.7 3.8 0.3 0.4 0.5 0.3 0.3 0.6 

Skin .................. 8.5 8.3 9.1 8.2 8.7 7.7 0.5 0.7 0.6 0.7 0.5 1.0 

Vision ................. 6.6 3.4 6.2 12.5 6.7 5.7 0.5 0.3 0.6 1.0 0.5 0.8 

Glaucoma ............... 4.2 1.4 4.2 8.9 4.2 3.6 0.4 0.2 0.5 0.8 0.4 0.7 

Hearing ................ 1.1 1.0 1.2 1.3 1.0 1.2 0.2 0.2 0.2 0.3 0.1 0.3 

Tests 

Blood pressure ............ 56.0 57.6 54.8 54.6 55.2 61.3 1.1 1.3 1.3 1.5 1.1 2.7 

Hemoglobin .............. 5.7 5.3 6.2 5.8 5.5 6.6 0.4 0.5 0.5 0.5 0.4 0.6 

Pap ................... 8.3 11.3 8.5 3.2 8.3 8.4 0.5 0.7 0.7 0.3 0.5 0.8 

Urinalysis ............... 13.5 19.6 9.1 8.0 13.0 16.9 0.7 1.2 0.6 0.6 0.8 1.2 

Pregnancy test ............ 1.2 2.7 * 0.0 1.1 2.3 0.1 0.2 . . . . . . 0.1 0.4 

Cholesterol measure ........ 3.6 2.1 4.7 5.1 3.5 4.1 0.2 0.2 0.4 0.4 0.2 0.6 

HIV serology ............. 0.4 0.8 *0.2 * 0.4 0.7 0.1 0.1 0.1 . . . 0.1 0.1 

Other STD1 test ........... 0.9 1.6 *0.3 * 0.7 1.9 0.1 0.2 0.1 . . . 0.1 0.4 

Imaging 

EKG1 ................. 2.6 1.2 2.8 4.9 2.6 3.2 0.2 0.1 0.3 0.4 0.2 0.4 

Mammography ............ 3.4 2.0 6.1 2.9 3.4 3.9 0.2 0.2 0.5 0.3 0.2 0.5 

Ultrasound .............. 3.7 5.3 2.5 2.2 3.4 4.3 0.3 0.5 0.3 0.2 0.3 0.5 

CAT scan/MRI1 ........... 1.1 1.0 1.2 1.2 1.1 1.2 0.1 0.1 0.2 0.1 0.1 0.2 

x ray .................. 5.8 4.4 6.4 7.5 5.8 6.2 0.3 0.3 0.4 0.5 0.3 0.6 

See footnotes at end of table. 
Series 13, No. 149 [ Page 31 

Table 10. Visits to office-based physicians and hospital outpatient departments for selected diagnostic and screening services ordered or 

provided, by age and race for women 15 years of age and over: United States, average annual 1997–98—Con. 

Age Race Age Race 

Diagnostic and screening All 15–44 45–64 65 years All 15–44 45–64 65 years 

services ordered or provided visits years years and over White Black visits years years and over White Black 

Number of visits per 100 women per year2 Standard error 

All visits ................ 3

421.7 340.4 444.3 662.9 3426.7 3413.8 13.3 12.7 14.9 26.8 15.3 30.1 

No services .............. 3

86.3 72.2 96.6 116.6 390.7 367.1 4.4 4.0 5.6 8.1 5.1 5.9 

Exams 

Breast ................. 3

47.1 44.7 51.9 47.0 347.4 345.0 2.5 3.0 3.3 3.7 2.7 4.8 

Pelvic ................. 3

58.1 68.3 51.6 34.7 359.0 356.6 3.5 4.9 3.7 3.1 4.0 5.8 

Rectal ................. 3

19.9 14.9 25.9 26.5 320.3 315.4 1.3 1.4 2.1 2.5 1.4 2.5 

Skin .................. 3

35.9 28.4 40.3 54.2 337.0 330.9 2.4 2.2 3.1 5.5 2.6 4.2 

Vision ................. 3

27.5 11.6 27.4 82.7 327.4 326.1 2.2 1.0 2.5 8.1 2.3 3.5 

Glaucoma ............... 3

17.3 4.6 18.5 59.0 317.0 317.0 1.6 0.6 2.1 5.9 1.7 2.9 

Hearing ................ 3

4.8 3.5 5.2 8.3 34.1 35.0 0.7 0.6 0.8 2.0 0.4 1.1 

Tests 

Blood pressure ............ 3

236.2 196.0 243.5 362.2 3235.9 3254.1 9.2 9.3 10.3 18.4 10.0 26.5 

Hemoglobin .............. 3

24.0 18.0 27.5 38.4 323.3 327.6 1.6 1.6 2.2 3.7 1.8 3.6 

Pap ................... 3

35.4 38.3 37.9 21.2 336.6 332.1 2.4 3.0 3.2 2.2 2.7 3.3 

Urinalysis ............... 3

57.1 66.7 40.3 53.2 356.4 365.8 3.5 5.1 3.0 4.4 3.9 8.7 

Pregnancy test ............ 3

5.2 9.0 * 0.0 34.8 37.8 0.5 0.9 . . . . . . 0.5 1.5 

Cholesterol measure ........ 3

15.3 7.1 21.0 33.6 314.6 318.2 1.0 0.8 1.8 3.3 1.1 2.7 

HIV serology ............. 3

1.8 2.7 *0.7 * 31.6 32.3 0.3 0.4 0.3 . . . 0.3 0.5 

Other STD1 test ........... 3

3.6 5.3 *1.5 * 33.0 37.0 0.5 0.8 0.5 . . . 0.5 1.2 

Imaging 

EKG1 ................. 3

10.9 4.0 12.2 32.2 310.6 314.4 0.8 0.4 1.3 3.1 0.9 2.0 

Mammography ............ 3

14.6 6.9 27.1 19.3 314.5 316.7 1.1 0.7 2.3 2.1 1.1 2.7 

Ultrasound .............. 3

15.4 17.9 11.1 14.6 314.7 316.1 1.3 2.0 1.3 1.7 1.3 2.3 

CAT scan/MRI1 ........... 3

4.6 3.2 5.4 7.6 34.6 34.9 0.3 0.3 0.7 1.0 0.3 0.9 

x ray .................. 3

24.4 15.1 28.3 49.8 324.5 326.5 1.3 0.9 2.0 3.8 1.5 2.8 

* Figure does not meet standard of reliability or precision. 

0.0 Quantity more than zero but less than 0.05. 

. . . Category not applicable. 

1EKG is electrocardiogram; CAT is computerized axial tomography; MRI is magnetic resonance imaging; HIV is human immunodeficiency virus; and STD is sexually transmitted diseases. 

2Based on U.S. Bureau of the Census monthly postcensal estimates of the civilian noninstitutionalized population of the United States as of July 1, 1997, and July 1, 1998. Figures have been adjusted 

for net underenumeration using the 1990 National Population Adjustment Matrix. 

3Age-adjusted. 
Page 32 [ Series 13, No. 149 

Table 11. Visits to office-based physicians and hospital outpatient departments for selected therapeutic and preventive services ordered or 

provided, by age and race for women 15 years of age and over: United States, average annual 1997–98 

Age Race Age Race 

Therapeutic and preventive All 15–44 45–64 65 years All 15–44 45–64 65 years 

services ordered or provided visits years years and over White Black visits years years and over White Black 

Number of visits in thousands Standard error 

All visits .................. 458,146 206,518 128,074 123,554 387,447 53,568 14,469 7,707 4,301 5,003 13,924 3,817 

No services ................ 270,120 111,182 76,065 82,873 228,895 32,222 9,704 5,022 3,010 3,625 9,345 2,657 

Counseling/education 

Diet ..................... 70,287 29,822 21,512 18,954 57,210 9,215 3,704 2,142 1,303 1,385 3,371 857 

Exercise .................. 51,045 21,592 16,530 12,924 42,987 5,851 3,219 1,806 1,140 1,121 2,999 627 

Prenatal instructions .......... 21,819 21,711 * * 17,663 3,140 2,115 2,114 . . . . . . 1,860 611 

Breast self-exams ............ 19,256 10,216 6,536 2,505 16,400 1,940 1,677 1,123 633 348 1,472 281 

Stress ................... 13,492 6,483 4,321 2,689 11,547 1,123 1,306 790 442 520 1,203 209 

Mental health ............... 12,722 6,819 3,694 2,210 10,943 1,160 1,251 723 454 339 1,142 172 

Family planning ............. 12,626 12,180 395 * 9,700 2,263 1,156 1,143 90 . . . 953 378 

Tobacco use ............... 12,502 6,704 4,043 1,755 10,759 1,522 992 745 388 237 890 219 

Injury prevention ............. 8,148 3,592 1,867 2,689 7,212 630 944 505 298 448 859 161 

Skin cancer prevention ......... 7,860 2,779 2,627 2,454 7,390 * 1,101 421 466 411 1,067 . . . 

HIV/STD1 transmission ......... 5,717 4,983 *627 * 3,896 1,542 932 807 211 . . . 709 317 

Growth/development .......... 2,217 1,923 *110 * 1,843 *185 469 445 44 . . . 424 60 

Other therapy 

Physiotherapy .............. 13,509 6,202 4,409 2,897 11,113 1,365 1,316 833 476 421 1,015 237 

Psychotherapy .............. 11,628 6,347 3,868 1,414 10,600 865 1,036 619 423 225 975 136 

Psycho-pharmacotherapy ....... 10,218 4,974 3,744 1,500 9,451 602 1,143 662 458 233 1,071 110 

Other .................... 36,286 14,413 10,821 11,052 31,234 3,739 2,207 1,045 715 965 2,057 402 

Percent distribution 

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

No services ................ 59.0 53.8 59.4 67.1 59.1 60.2 1.1 1.4 1.2 1.2 1.1 1.9 

Counseling/education 

Diet ..................... 15.3 14.4 16.8 15.3 14.8 17.2 0.7 0.9 0.9 0.9 0.7 1.3 

Exercise .................. 11.1 10.5 12.9 10.5 11.1 10.9 0.6 0.8 0.8 0.8 0.7 1.1 

Prenatal instructions .......... 4.8 10.5 * * 4.6 5.9 0.4 0.9 . . . . . . 0.4 1.1 

Breast self-exams ............ 4.2 5.0 5.1 2.0 4.2 3.6 0.3 0.5 0.5 0.3 0.4 0.5 

Stress ................... 2.9 3.1 3.4 2.2 3.0 2.1 0.3 0.4 0.3 0.4 0.3 0.4 

Mental health ............... 2.8 3.3 2.9 1.8 2.8 2.2 0.3 0.3 0.3 0.3 0.3 0.3 

Family planning ............. 2.8 5.9 0.3 * 2.5 4.2 0.2 0.5 0.1 . . . 0.2 0.6 

Tobacco use ............... 2.7 3.3 3.2 1.4 2.8 2.8 0.2 0.4 0.3 0.2 0.2 0.4 

Injury prevention ............. 1.8 1.7 1.5 2.2 1.9 1.2 0.2 0.2 0.2 0.4 0.2 0.3 

Skin cancer prevention ......... 1.7 1.4 2.1 2.0 1.9 * 0.2 0.2 0.4 0.3 0.3 . . . 

HIV/STD1 transmission ......... 1.3 2.4 *0.5 * 1.0 2.9 0.2 0.4 0.2 . . . 0.2 0.6 

Growth/development .......... 0.5 0.9 *1.0 * 0.5 *0.4 0.1 0.2 0.0 . . . 0.1 0.1 

Other therapy 

Physiotherapy .............. 3.0 3.0 3.4 2.3 2.9 2.6 0.3 0.4 0.4 0.3 0.3 0.4 

Psychotherapy .............. 2.5 3.1 3.0 1.1 2.7 1.6 0.2 0.3 0.3 0.2 0.2 0.2 

Psycho-pharmacotherapy ....... 2.2 2.4 2.9 1.2 2.4 1.1 0.2 0.3 0.3 0.2 0.3 0.2 

Other .................... 7.9 7.0 8.5 8.9 8.1 7.0 0.4 0.5 0.5 0.6 0.4 0.6 

See footnotes at end of table. 
Series 13, No. 149 [ Page 33 

Table 11. Visits to office-based physicians and hospital outpatient departments for selected therapeutic and preventive services ordered or 

provided, by age and race for women 15 years of age and over: United States, average annual 1997–98—Con. 

Age Race Age Race 

Therapeutic and preventive All 15–44 45–64 65 years All 15–44 45–64 65 years 

services ordered or provided visits years years and over White Black visits years years and over White Black 

Number of visits per 100 women per year2 Standard error 

All ..................... 3

421.7 346.6 474.4 910.3 3426.7 3413.8 13.3 12.9 15.9 36.9 15.3 30.1 

No services ................ 3

248.1 183.3 263.9 444.6 3250.7 3254.6 8.9 8.3 10.4 19.4 10.3 21.8 

Counseling/education 

Diet ..................... 3

64.8 49.2 74.6 101.7 363.0 371.3 3.4 3.5 4.5 7.4 3.7 6.5 

Exercise .................. 3

47.2 35.6 57.3 69.3 347.5 344.8 3.0 3.0 4.0 6.0 3.3 4.9 

Prenatal instructions .......... 3

20.0 35.8 * * 320.2 319.8 1.9 3.5 . . . . . . 2.1 3.9 

Breast self-exams ............ 3

17.9 16.8 22.7 13.4 318.5 313.9 1.6 1.9 2.2 1.9 1.7 2.0 

Stress ................... 3

12.5 10.7 15.0 14.4 312.9 38.8 1.2 1.3 1.5 2.8 1.3 1.6 

Mental health ............... 3

11.8 11.2 12.8 11.9 312.3 38.7 1.2 1.2 1.6 1.8 1.3 1.3 

Family planning ............. 3

11.6 20.1 1.4 * 310.8 314.4 1.1 1.9 0.3 . . . 1.1 2.4 

Tobacco use ............... 3

11.6 11.0 14.0 9.4 312.1 310.9 0.9 1.2 1.3 1.3 1.0 1.5 

Injury prevention ............. 3

7.4 5.9 6.5 14.4 37.9 35.0 0.9 0.8 1.0 2.4 0.9 1.3 

Skin cancer prevention ......... 3

7.2 4.6 9.1 13.2 38.1 * 1.0 0.7 1.6 2.2 1.2 . . . 

HIV/STD1 transmission ......... 3

5.3 8.2 *2.2 * 34.5 310.2 0.9 1.3 0.7 . . . 0.8 2.1 

Growth/development .......... 3

2.0 3.2 * * 32.1 3*1.2 0.4 0.7 . . . . . . 0.5 0.4 

Other therapy 

Physiotherapy .............. 3

12.5 10.2 15.3 15.5 312.3 310.3 1.2 1.4 1.7 2.3 1.1 1.8 

Psychotherapy .............. 3

10.8 10.5 13.4 7.6 312.0 36.5 1.0 1.0 1.5 1.0 1.1 1.0 

Psycho-pharmacotherapy ....... 3

9.5 8.2 13.0 8.0 310.6 34.8 1.1 1.1 1.6 1.2 1.2 0.9 

Other .................... 3

33.4 23.8 37.5 59.3 334.2 329.0 2.0 1.7 2.5 5.2 2.2 3.2 

* Figure does not meet standard of reliability or precision. 

. . . Category not applicable. 

1HIV is human immunodeficiency virus and STD is sexually transmitted diseases. 

2Based on U.S. Bureau of the Census monthly postcensal estimates of the civilian noninstitutionalized population of the United States as of July 1, 1997, and July 1, 1998. Figures have been adjusted 

for net underenumeration using the 1990 National Population Adjustment Matrix. 

3Age-adjusted. 
number of medications provided or prescribed, by age and race for women 15 years of age and over: United States, average annual 

Number of medications provided or prescribed Number of medications provided or prescribed 

All visits 0 1 2 3 4 and over All visits 0 1 2 3 4 and over 

Page 34 [ Series 13, No. 149 Number of visits in thousands Standard error 

499,785 174,837 138,521 85,604 43,812 57,011 14,828 6,428 4,644 3,312 1,968 3,149 

230,628 90,149 72,925 39,670 16,424 11,460 7,896 4,286 2,865 1,855 995 705 

36,487 43,937 34,600 25,002 13,726 19,222 4,386 1,781 1,356 1,237 730 1,233 

32,670 40,751 30,996 20,932 13,662 26,329 5,076 1,901 1,437 1,072 827 1,844 

419,240 147,159 116,297 72,127 36,127 47,530 14,332 6,247 4,334 3,109 1,774 2,975 

87,478 73,368 59,287 32,579 13,314 8,930 7,462 3,972 2,668 1,750 908 639 

114,875 37,642 29,771 20,974 10,895 15,592 4,187 1,728 1,294 1,118 612 1,099 

116,887 36,149 27,239 18,574 11,918 23,007 4,883 1,794 1,316 1,018 781 1,781 

62,489 20,876 17,414 10,017 6,133 8,048 4,001 1,227 1,301 872 576 902 33,521 12,474 10,759 5,482 2,565 2,241 2,228 884 938 509 288 302 16,533 4,613 3,787 2,870 2,234 3,029 1,096 385 363 334 239 345 

12,435 3,790 2,868 1,665 1,335 2,778 1,369 390 377 252 272 514 

Percent distribution 

100.0 35.0 27.7 17.1 8.8 11.4 . . . 0.9 0.5 0.4 0.3 0.5 

100.0 39.1 31.6 17.2 7.1 5.0 . . . 1.2 0.8 0.5 0.3 0.3 100.0 32.2 25.4 18.3 10.1 14.1 . . . 1.0 0.7 0.6 0.4 0.7 

100.0 30.7 23.4 15.8 10.3 19.9 . . . 1.1 0.7 0.6 0.5 1.0 100.0 35.1 27.7 17.2 8.6 11.3 . . . 1.0 0.6 0.5 0.3 0.5 

100.0 39.1 31.6 17.4 7.1 4.8 . . . 1.3 0.9 0.6 0.4 0.3 

100.0 32.8 25.9 18.3 9.5 13.6 . . . 1.1 0.7 0.7 0.4 0.7 100.0 30.9 23.3 15.9 10.2 19.7 . . . 1.1 0.7 0.6 0.5 1.0 100.0 33.4 27.9 16.0 9.8 12.9 . . . 1.4 1.0 0.7 0.6 0.9 

100.0 37.2 32.1 16.4 7.7 6.7 . . . 1.8 1.3 0.8 0.8 0.8 

100.0 27.9 22.9 17.4 13.5 18.3 . . . 1.9 1.6 1.4 1.1 1.6 100.0 30.5 23.1 13.4 10.7 22.3 . . . 2.3 2.3 1.5 1.4 2.4 

Number of visits per 100 women per year1 

459.9 160.9 127.6 79.0 40.3 52.1 13.6 5.9 4.3 3.1 1.8 2.9 

380.1 148.6 120.2 65.4 27.1 18.9 13.0 7.1 4.9 3.1 1.6 1.2 473.5 152.4 120.0 86.7 47.6 66.7 15.2 6.2 4.7 4.3 2.5 4.3 

711.8 218.6 166.3 112.3 73.3 141.3 27.2 10.2 7.7 5.8 4.4 9.9 
number of medications provided or prescribed, by age and race for women 15 years of age and over: United States, average annual 

Number of medications provided or prescribed Number of medications provided or prescribed 

All visits 0 1 2 3 4 and over All visits 0 1 2 3 4 and over 

Number of visits per 100 women per year1 Standard error 

461.9 162.9 129.0 79.7 39.5 50.8 15.8 7.0 4.8 3.5 1.9 3.1 385.6 150.9 121.9 67.0 27.4 18.4 15.3 8.2 5.5 3.6 1.9 1.3 472.0 154.7 122.3 86.2 44.8 64.1 17.2 7.1 5.3 4.6 2.5 4.5 

707.6 218.8 164.9 112.5 72.2 139.3 29.5 10.8 8.0 6.2 4.7 10.8 

478.5 156.4 129.3 76.0 48.8 68.0 31.4 9.1 9.6 6.8 4.8 7.9 380.7 141.7 122.2 62.3 29.1 25.5 25.3 10.0 10.6 5.8 3.3 3.4 507.2 141.5 116.2 88.1 68.5 92.9 33.6 11.8 11.1 10.2 7.3 10.6 

765.9 233.4 176.6 102.6 82.2 171.1 84.3 24.0 23.2 15.5 16.7 31.7 

tcensal estimates of the civilian noninstitutionalized population of the United States as of July 1, 1997, and July 1, 1998. Figures have been adjusted for net underenumeration using the 1990 National 

Series 13, No. 149 [ Page 35 
Page 36 [ Series 13, No. 149 

Table 13. Drug mentions of the 10 generic substances most frequently used at ambulatory care visits by age and race for women 15 years 

of age and over: United States, average annual 1997–98 

Rate per 

Number in Standard Percent Standard 100 women Standard 

Generic substance thousands1 error distribution error per year2 error 

All visits 

Acetaminophen ......................... 31,361 1,666 3.6 0.2 3

28.9 1.5 

Estrogens ............................. 19,401 1,290 2.2 0.1 3

18.2 1.2 

Hydrochlorothiazide ....................... 13,885 1,055 1.6 0.1 3

12.7 1.0 

Ibuprofen ............................. 13,139 722 1.5 0.1 3

12.2 0.7 

Levothyroxine .......................... 11,879 988 1.4 0.1 3

10.9 0.9 

Estradiol .............................. 11,439 1,166 1.3 0.1 3

10.6 1.1 

Furosemide ............................ 10,835 830 1.2 0.1 3

8.7 0.8 

Medroxyprogesterone ..................... 10,700 728 1.2 0.1 3

10.1 0.7 

Hydrocodone ........................... 10,651 685 1.2 0.1 3

9.8 0.6 

Aspirin ............................... 10,453 686 1.2 0.1 3

9.4 0.6 

All others ............................. 728,668 28,170 83.5 0.3 3

668.9 25.8 

Age 

15–44 years: 

Acetaminophen ........................ 14,454 829 4.3 0.2 23.8 1.4 

Vitamin A ............................ 8,818 1,433 2.6 0.4 14.5 2.4 

Ergocalciferol ......................... 8,758 1,433 2.6 0.4 14.4 2.4 

Pyridoxine ........................... 8,704 1,438 2.6 0.4 14.4 2.4 

Thiamine ............................ 8,678 1,436 2.6 0.4 14.3 2.4 

Riboflavin ........................... 8,628 1,438 2.5 0.4 14.2 2.4 

Estradiol ............................ 8,119 906 2.4 0.2 13.4 1.5 

Ibuprofen ............................ 7,056 460 2.1 0.1 11.6 0.8 

Amoxicillin ........................... 6,598 502 1.9 0.1 10.9 0.8 

Hydrocodone ......................... 5,093 392 1.5 0.1 8.4 0.7 

All others ............................ 255,400 10,469 75.1 1.6 421.0 17.2 

45–64 years: 

Estrogens ........................... 11,184 840 4.4 0.3 38.8 2.9 

Acetaminophen ........................ 9,025 593 3.5 0.2 31.3 2.1 

Medroxyprogesterone .................... 5,740 493 2.3 0.2 19.9 1.7 

Hydrochlorothiazide ..................... 5,215 436 2.1 0.1 18.1 1.5 

Levothyroxine ......................... 4,131 462 1.6 0.2 14.3 1.6 

Ibuprofen ............................ 3,747 334 1.5 0.1 13.0 1.2 

Furosemide .......................... 2,949 347 1.2 0.1 10.2 1.2 

Albuterol ............................ 2,940 323 1.2 0.1 10.2 1.1 

Hydrocodone ......................... 2,919 267 1.2 0.1 10.1 0.9 

Aspirin ............................. 2,914 296 1.1 0.1 10.1 1.0 

All others ............................ 203,985 8,863 80.1 0.5 707.6 30.7 

65 years and over: 

Acetaminophen ........................ 7,882 696 2.8 0.2 42.3 3.7 

Hydrochlorothiazide ..................... 7,371 657 2.7 0.2 39.6 3.5 

Furosemide .......................... 7,124 577 2.6 0.1 38.2 3.1 

Estrogens ........................... 6,671 562 2.4 0.2 35.8 3.0 

Aspirin ............................. 6,143 501 2.2 0.1 33.0 2.7 

Levothyroxine ......................... 5,108 469 1.8 0.1 27.4 2.5 

Digoxin ............................. 4,851 435 1.8 0.1 26.0 2.3 

Potassium replacement solutions ............. 3,825 398 1.4 0.1 20.5 2.1 

Lisinopril ............................ 3,655 374 1.3 0.1 19.6 2.0 

Atenolol ............................. 3,410 340 1.2 0.1 18.3 1.8 

All others ............................ 221,315 11,587 79.8 0.4 1,187.4 62.1 

Race 

White: 

Acetaminophen ........................ 25,610 1,491 3.5 0.2 3

28.2 1.6 

Estrogens ........................... 17,156 1,183 2.4 0.1 3

18.8 1.3 

Levothyroxine ......................... 10,888 918 1.5 0.1 3

11.7 1.0 

Hydrochlorothiazide ..................... 10,668 868 1.5 0.1 3

11.2 0.9 

Ibuprofen ............................ 10,245 681 1.4 0.1 3

11.4 0.8 

Estradiol ............................ 10,192 1,052 1.4 0.1 3

11.6 1.2 

Medroxyprogesterone .................... 9,205 643 1.3 0.1 3

10.3 0.7 

Furosemide .......................... 9,069 736 1.2 0.1 3

9.4 0.8 

Hydrocodone ......................... 8,822 707 1.2 0.1 3

9.7 0.8 

Amoxicillin ........................... 8,743 597 1.2 0.1 3

9.8 0.7 

All others ............................ 608,488 26,597 83.5 0.4 3

664.4 28.9 

See footnotes at end of table. 
Series 13, No. 149 [ Page 37 

Table 13. Drug mentions of the 10 generic substances most frequently used at ambulatory care visits by age and race for women 15 years 

of age and over: United States, average annual 1997–98—Con. 

Rate per 

Number in Standard Percent Standard 100 women Standard 

Generic substance thousands1 error distribution error per year2 error 

Race—Continued 

Black: 

Acetaminophen ........................ 4,570 443 4.0 0.3 3

34.8 3.6 

Hydrochlorothiazide ..................... 2,846 550 2.5 0.3 3

24.4 4.8 

Ibuprofen ............................ 2,398 213 2.1 0.2 3

17.7 1.7 

Estrogens ........................... 1,799 339 1.6 0.3 3

15.4 2.8 

Insulin .............................. 1,746 264 1.5 0.2 3

15.4 2.4 

Iron preparations ....................... 1,714 336 1.5 0.3 3

12.1 2.4 

Furosemide .......................... 1,645 275 1.4 0.2 3

14.8 2.5 

Nifedipine ........................... 1,537 269 1.4 0.2 3

13.4 2.3 

Albuterol ............................ 1,525 183 1.3 0.2 3

11.7 1.5 

Hydrocodone ......................... 1,466 300 1.3 0.2 3

10.9 2.2 

All others ............................ 92,612 7,787 81.3 0.7 3

730.6 65.0 

1Frequency of mention combines single-ingredient agents with mentions of the agent as an ingredient in a combination drug. 

2Based on U.S. Bureau of the Census monthly postcensal estimates of the civilian noninstitutionalized population of the United States as of July 1, 1997, and July 1, 1998. Figures have been adjusted 

for net underenumeration using the 1990 National Population Adjustment Matrix. 

3Age-adjusted. 
Page 38 [ Series 13, No. 149 

Table 14. Drug mentions of the 10 therapeutic classes of drugs most frequently used at ambulatory care visits by age and race for women 

15 years of age and over: United States, average annual 1997–98 

Rate per 

Number in Standard Percent Standard 100 women Standard 

Therapeutic classes (4-digit) thousands error distribution error per year1 error 

All visits 

Analgesics, nonnarcotic .................... 34,375 1,800 4.7 0.2 2

31.5 1.7 

Antidepressants ......................... 33,692 1,985 4.7 0.2 2

31.3 1.8 

Estrogens/progestins ...................... 31,664 1,987 4.4 0.2 2

29.7 1.9 

Nonsteroidal anti-inflammatory drug (NSAID) ....... 28,911 1,333 4.0 0.2 2

26.7 1.2 

Disorders, acid/peptic ...................... 22,601 1,291 3.1 0.1 2

20.8 1.2 

Antihistamines .......................... 22,091 1,273 3.1 0.1 2

20.5 1.2 

Vitamins/minerals ........................ 22,000 1,924 3.0 0.2 2

20.1 1.8 

Antiasthmatics/bronchodilators ................ 20,745 1,527 2.9 0.2 2

19.1 1.4 

Blood glucose regulators ................... 20,536 1,434 2.8 0.2 2

18.9 1.3 

Calcium channel blockers ................... 20,248 1,280 2.8 0.1 2

18.3 1.2 

All other classes ......................... 467,766 18,203 64.6 0.5 2

189.0 6.5 

Age 

15–44 years: 

Vitamins/minerals ....................... 15,356 1,738 6.0 0.6 25.3 2.9 

Nonsteroidal anti-inflammatory drug (NSAID) ...... 14,162 715 5.6 0.3 23.3 1.2 

Antidepressants ........................ 13,514 1,043 5.3 0.3 22.3 1.7 

Analgesics, nonnarcotic ................... 12,831 805 5.0 0.3 21.2 1.3 

Antihistamines ......................... 10,795 690 4.2 0.2 17.8 1.1 

Contraceptives ........................ 9,767 961 3.8 0.3 16.1 1.6 

Penicillins ........................... 8,252 539 3.2 0.2 13.6 0.9 

Antiasthmatics/bronchodilators ............... 7,195 662 2.8 0.2 11.9 1.1 

Cephalosporins ........................ 7,058 574 2.8 0.2 11.6 1.0 

Estrogens/progestins .................... 6,391 665 2.5 0.2 10.5 1.1 

All other classes ....................... 149,527 5,903 58.7 0.8 127.5 4.9 

45–64 years: 

Estrogens/progestins .................... 16,791 1,200 7.6 0.4 58.3 4.2 

Antidepressants ........................ 12,502 834 5.6 0.3 43.4 2.9 

Analgesics, nonnarcotic ................... 9,909 679 4.5 0.3 34.4 2.4 

Disorders, acid/peptic .................... 8,720 666 3.9 0.3 30.3 2.3 

Nonsteroidal anti-inflammatory drug (NSAID) ...... 8,670 569 3.9 0.2 30.1 2.0 

Blood glucose regulators .................. 8,369 808 3.8 0.3 29.0 2.8 

Ace inhibitors ......................... 7,300 640 3.3 0.2 25.3 2.2 

Antihistamines ......................... 7,085 579 3.2 0.2 24.6 2.0 

Antiasthmatics/bronchodilators ............... 6,738 691 3.0 0.3 23.4 2.4 

Calcium channel blockers .................. 6,153 522 2.8 0.2 21.4 1.8 

All other classes ....................... 129,808 5,596 58.5 0.7 450.3 19.4 

65 years and over: 

Diuretics ............................ 11,892 953 4.8 0.2 63.8 5.1 

Calcium channel blockers .................. 11,765 836 4.8 0.2 63.1 4.5 

Analgesics, nonnarcotic ................... 11,635 851 4.7 0.3 62.4 4.6 

Ace inhibitors ......................... 11,340 818 4.6 0.2 60.8 4.4 

Blood glucose regulators .................. 9,104 725 3.7 0.2 48.9 3.9 

Disorders, acid/peptic .................... 8,525 686 3.4 0.2 45.7 3.7 

Estrogens/progestins .................... 8,482 720 3.4 0.2 45.5 3.9 

Antidepressants ........................ 7,676 634 3.1 0.2 41.2 3.4 

Beta blockers ......................... 7,428 678 3.0 0.2 39.9 3.6 

Antiasthmatics/bronchodilators ............... 6,813 694 2.8 0.2 36.6 3.7 

All other classes ....................... 153,079 7,981 61.8 0.6 821.3 42.8 

Race 

White:2 

Antidepressants ........................ 30,090 1,868 5.0 0.2 233.5 2.1 

Estrogens/progestins .................... 27,847 1,832 4.6 0.2 2

30.8 2.0 

Analgesics, nonnarcotic ................... 27,748 1,549 4.6 0.2 2

30.1 1.7 

Nonsteroidal anti-inflammatory drug (NSAID) ...... 23,090 1,229 3.8 0.2 2

25.7 1.4 

Antihistamines ......................... 18,950 1,193 3.1 0.1 2

21.2 1.3 

Disorders, acid/peptic .................... 18,677 1,190 3.1 0.1 2

20.2 1.3 

Vitamins/minerals ....................... 18,007 1,797 3.0 0.3 2

20.0 2.0 

Antiasthmatics/bronchodilators ............... 17,196 1,382 2.8 0.2 2

18.7 1.5 

Ace inhibitors ......................... 16,186 1,186 2.7 0.1 2

17.0 1.3 

Diuretics ............................ 15,699 1,262 2.6 0.1 2

16.3 1.3 

All other classes ....................... 392,496 6,554 63.2 0.7 2

426.2 17.89 

See footnotes at end of table. 
Series 13, No. 149 [ Page 39 

Table 14. Drug mentions of the 10 therapeutic classes of drugs most frequently used at ambulatory care visits by age and race for women 

15 years of age and over: United States, average annual 1997–98—Con. 

Rate per 

Number in Standard Percent Standard 100 women Standard 

Therapeutic classes (4-digit) thousands error distribution error per year1 error 

Race—Continued 

Black:2 

Analgesics, nonnarcotic ................... 5,309 546 5.6 0.4 242.2 4.6 

Nonsteroidal anti-inflammatory drug (NSAID) ...... 4,874 510 5.1 0.3 2

37.4 4.3 

Calcium channel blockers .................. 4,483 618 4.7 0.4 2

38.8 5.3 

Blood glucose regulators .................. 4,341 580 4.6 0.4 2

37.8 5.0 

Ace inhibitors ......................... 3,399 369 3.6 0.3 2

30.0 3.3 

Diuretics ............................ 3,316 502 3.5 0.3 2

29.0 4.5 

Estrogens/progestins .................... 3,208 455 3.4 0.4 2

25.7 3.6 

Antiasthmatics/bronchodilators ............... 3,016 332 3.2 0.4 2

23.3 2.6 

Vitamins/minerals ....................... 2,955 353 3.1 0.4 2

20.6 2.5 

Antidepressants ........................ 2,803 293 2.9 0.3 2

23.0 2.4 

All other classes ....................... 57,606 5,089 60.4 1.2 2

455.8 42.2 

1Based on U.S. Bureau of the Census monthly postcensal estimates of the civilian noninstitutionalized population of the United States as of July 1, 1997, and July 1, 1998. Figures have been adjusted 

for net underenumeration using the 1990 National Population Adjustment Matrix. 

2Age-adjusted. 
Page 40 [ Series 13, No. 149


Table 15. Use of ambulatory care by women with nonpregnancy diagnoses and men: United States, average annual 1997–98


Number of Number of 

visits per Standard visits per Standard Rate Standard 

Characteristic 100 women1 error 100 men1 error ratio error 

Total2 ......................................... 420.7 12.4 315.4 9.8 †

1.33 0.06 

Age 

15–44 years ..................................... 310.0 10.0 198.1 6.5 †

1.56 0.07 

45–64 years ..................................... 472.9 15.2 353.4 11.8 †

1.34 0.06 

65 years and over .................................. 711.6 27.2 654.2 26.8 1.09 0.06 

Race2 

White ......................................... 422.7 14.3 315.3 11.0 †1.34 0.07 

Black .......................................... 438.2 29.7 329.9 21.8 †

1.33 0.13 

Place of visit2 

Primary care ..................................... 205.2 8.6 129.8 6.3 †1.58 0.10 

Surgical care ..................................... 74.7 3.9 69.3 3.4 1.08 0.08 

Nonsurgical care .................................. 73.5 3.7 59.8 3.1 †

1.23 0.09 

Outpatient department ............................... 30.8 2.5 22.0 1.9 †

1.40 0.17 

Emergency department .............................. 36.5 1.3 34.6 1.3 1.05 0.06 

Major reason for visit2,3 

Acute condition ................................... 127.7 5.0 94.6 4.0 †1.35 0.08 

Chronic condition .................................. 161.5 5.5 126.7 4.5 †

1.27 0.06 

Pre/post surgery ................................... 32.6 1.7 26.7 1.4 †

1.22 0.09 

Nonillness ....................................... 54.8 3.0 27.5 1.9 †

2.00 0.17 

Unknown ....................................... 7.7 0.8 5.3 0.6 1.43 0.22 

Treatment2 

No diagnostic/screening services ........................ 86.5 4.3 72.2 3.6 †1.20 0.08 

No therapeutic/preventive services ....................... 257.2 8.5 194.1 6.6 †

1.33 0.06 

Classes of drugs mentioned2 (2-digit) 

Cardiovascular-renal drugs ............................ 96.9 5.4 96.7 6.0 1.00 0.08 

Hormones/hormonal mechanisms ........................ 85.4 4.4 33.0 2.0 †

2.59 0.20 

Relief of pain ..................................... 84.5 3.5 71.9 2.9 †

1.18 0.07 

Respiratory tract ................................... 63.3 3.2 42.1 2.5 †

1.50 0.12 

Central nervous system .............................. 63.4 3.5 32.9 2.1 †

1.93 0.16 

Antimicrobial agents ................................ 59.1 2.3 44.6 1.8 †

1.32 0.08 

Metabolic/nutrients ................................. 45.4 2.7 25.7 1.7 †

1.77 0.16 

Skin/mucous membrane .............................. 34.8 1.9 24.5 1.3 †

1.42 0.11 

All others ....................................... 132.6 5.6 99.5 4.7 †

1.33 0.08 

† Rate ratio is significant at the 95% confidence level. 

1Based on U.S. Bureau of the Census monthly postcensal estimates of the civilian noninstitutionalized population of the United States as of July 1, 1997, and July 1, 1998. Figures have been adjusted 

for net underenumeration using the 1990 National Population Adjustment Matrix. 

2Age-adjusted. 

3Visits to emergency departments are not included in this section. 
Series 13, No. 149 [ Page 41 

Appendix 

Technical Notes 

Estimation 

Statistics from the 1997 and 1998 

NAMCS and NHAMCS were derived 

by multistage estimation procedures that 

produce essentially unbiased estimates. 

The estimation for NAMCS has four 

basic components: (a) inflation by 

reciprocals of the probabilities of 

selection, (b) adjustment for 

nonresponse, (c) a ratio adjustment to 

fixed totals, and (d) weight smoothing. 

The estimation for NHAMCS has three 

basic components: (a) inflation by 

reciprocals of the sampling selection 

probabilities, (b) adjustment for 

nonresponse, and (c) population 

weighting ratio adjustment. Beginning 

with 1997, the population weighting 

ratio adjustment for OPD estimates was 

replaced by an adjustment which 

controls for effects of rotating hospital 

sample panels into and out of the 

sample each year. (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 1 year.) 

The sampling weights of some OPD’s 

were permanently trimmed to prevent 

single OPD’s from contributing more 

than 15 percent of their region’s total to 

OPD visit estimates. For the annual 

average estimates presented in this 

report, the annual sampling weights for 

each survey were divided by 2. 

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 

out of 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 that were used 

in tests of significance for this report 

were approximated 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 (17). 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 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 for both surveys. 

Adjustments for survey 

nonresponse—Estimates from NAMCS 

data were adjusted to account for 

sample physicians who were in scope 

but did not participate in the study. This 

adjustment was calculated to minimize 

the impact of nonresponse on final 

estimates. The weights of visits for 

physicians similar to the nonrespondent 

physicians were inflated to account for 

visits represented by the nonrespondent 

physicians. For this purpose, physicians 

were judged similar if they had the 

same specialty designation and practiced 

in the same primary sampling unit 

(PSU). 

NHAMCS data were adjusted to 

account for nonresponse at the hospital 

level and at the ED and OPD clinic 

level. 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 a MSA versus not 

in an MSA). The weights of visits from 

responding ED’s and OPD clinics were 

inflated to account for visits to similar 

nonrespondent ED’s/clinics where 

ED’s/clinics were judged to be similar if 

they were in the same region and 

ED/clinic group. For this purpose, there 

were six OPD clinic groups: (a) general 

medicine, (b) pediatrics, (c) surgery, (d) 

OB/GYN, (e) alcohol and/or substance 

abuse, and (f) other OPD clinics. ED’s 

or OPD’s were judged similar if they 

were in the same ED or clinic group 

within the hospital. 

Adjustments for item nonresponse— 

Weighted item nonresponse rates were 

5.0 percent or less for all data items 

included in this report with these 

exceptions: Is patient pregnant 

(19.7 percent), does patient belong to an 

HMO (13.5 percent), or cause of injury 

(19.3 percent). Additional information 

on item nonresponse for data items not 

included in this report and for item 

nonresponse rates by setting has been 

published (6–11). 

Missing data for several of the 

items mentioned in this report were 

imputed by randomly assigning a value 

from a Patient Record form with similar 

characteristics. These items include 

patient’s visit date and year of birth 

(used to determine age), sex, and race. 

In the NAMCS, imputations were based 

on physician specialty, geographic 

region, and 3-digit ICD–9–CM code for 

primary diagnosis. For the NHAMCS, 

imputations were based on ED size, 

geographic region, ‘‘immediacy with 

which patient should be seen,’’ and 

3-digit ICD–9–CM code for primary 

diagnosis. For OPD data, the grouping 

used was geographic region, OPD size 

by clinic, and 3-digit ICD–9–CM code 

for primary diagnosis. 
Page 42 [ Series 13, No. 149 

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 or more cases are 

asterisked only if the relative standard 

error of the estimate exceeds 30 percent. 

Tests of Significance and 

Rounding 

In this report, the determination of 

statistical inference is based on the 

two-tailed t-test and the chi-square test. 

The Bonferroni inequality was used to 

establish the critical value for 

statistically significant differences (0.05 

level of significance) based on the 

number of possible comparisons within 

a particular variable (or combination of 

variables) of interest. Terms relating to 

differences such as ‘‘greater than’’ or 

‘‘less than’’ indicate that the difference 

is statistically significant. A lack of 

comment regarding the difference 

between any two estimates does not 

mean that the difference was tested and 

found to be not significant. Chi-square 

tests were performed using the 

SUDAAN routine PROC CROSSTAB 

that takes into account the complex 

sample designs used in the NAMCS and 

NHAMCS. 

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. 

Population Figures and Rate 

Calculation 

The population figures used in 

computing annual visit rates by age, sex, 

and race for this report are shown in 

table I. The figures represent an average 

of the U.S. Bureau of the Census 

estimates of the civilian, 

noninstitutionalized population as of 

July 1, 1997, and July 1, 1998. Figures 

are based on monthly postcensal 

estimates and are consistent with an 

unpublished hard-copy national 

estimates release package PPL-91 (U.S. 

Population Estimates by Age, Sex, Race 

and Hispanic Origin: 1990–98) and have 

been adjusted for net underenumeration 

using the 1990 National Population 

Adjustment Matrix. 

Physician specialty groupings 

The NAMCS survey design grouped 

physicians into 15 strata, or specialty 

groups, for sampling purposes. One 

stratum, doctors of osteopathy, was 

based on information from the American 

Osteopathic Association (AOA). The 

other groups (general and family 

practice, internal medicine, pediatrics, 

general surgery, obstetrics and gynecology, 

orthopedic surgery, cardiovascular 

diseases, dermatology, urology, psychiatry, 

neurology, ophthalmology, otolaryngology, 

and a residual category of other 

specialties) were developed based on 

information from the American Medical 

Association (AMA). 

Estimates are presented in this 

report with doctors of osteopathy 

combined with doctors of medicine 

based on the physician’s specialty. In 

several tables and charts, office visits are 

presented using broader categories of 

primary care, and surgical and 

nonsurgical specialties. Table II shows 

the specialties used to define these 

categories. 

Definition of Terms 

Ambulatory patient—An ambulatory 

patient is an individual seeking personal 

health services who is not currently 

admitted to any health care institution 

on the premises. 

Drug mention—A drug mention is the 

physician’s entry on the Patient Record 

form of a pharmaceutical agent—by any 

route of administration—for prevention, 

diagnosis, or treatment. Generic as well 

as brand-name drugs are included, as are 

nonprescription and prescription drugs. 

Along with all new drugs, the physician 

also records continued medications if 

the patient was specifically instructed 

during the visit to continue the 

medication. Physicians may report up to 

six medications per visit. 

Drug visit—A drug visit is a visit at 

which medication was prescribed or 

provided by the physician. 

Emergency department—Hospital 

facility for the provision of unscheduled 

outpatient services to patients whose 

Table I. Average annual U.S. population estimates used in computing annual visit rates for 

the National Ambulatory Medical Care Survey and the National Hospital Ambulatory Medical 

Care Survey, by age, sex, and race: July 1, 1997, and July 1, 1998 

15 years 15–44 45–64 65 years 

Sex and race and over years years and over 

All races .................. 208,284,498 120,250,794 55,822,124 32,211,580 

Male ................... 100,148,261 59,580,114 26,994,545 13,573,602 

Female ................. 108,136,237 60,670,680 28,827,579 18,637,979 

White ................... 173,918,060 97,608,345 47,649,273 28,660,443 

Male ................... 84,440,231 48,985,115 23,312,372 12,142,745 

Female ................. 89,477,829 48,623,230 24,336,901 16,517,698 

Black .................... 24,853,137 16,317,247 5,852,183 2,683,708 

Male ................... 11,164,870 7,511,947 2,592,851 1,060,073 

Female ................. 13,688,267 8,805,300 3,259,332 1,623,635 

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, 1997, and July 1, 1998. Figures are consistent with the downloadable series, ‘‘U.S. Population 

estimates by age, sex, race, and Hispanic origin: 1980 to 1998 (with extension to September 1, 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. 
Series 13, No. 149 [ Page 43 

Table II. Reclassification of physician specialty for use with National Ambulatory Medical Care Survey data 

Physician specialty group Physician specialty 

Primary care specialties	 General/family practice, internal medicine, adolescent medicine, pediatrics, pediatric sports medicine, adolescent medicine 

(internal medicine), gynecology, maternal and fetal medicine, obstetrics and gynecology, obstetrics, geriatric medicine 

(internal medicine), and sports medicine (internal medicine). 

Surgical specialties	 Hand surgery, adult reconstructive orthopedics, foot and ankle orthopedics, musculoskeletal oncology, pediatric 

orthopedics, orthopedic surgery, sports medicine (orthopedic surgery), orthopedic surgery of the spine, orthopedic trauma, 

gynecological oncology, urology, pediatric urology, ophthalmology, pediatric ophthalmology, otology, otolaryngology, 

pediatric otolaryngology, general surgery, critical care medicine (obstetrics and gynecology), abdominal surgery, 

cardiovascular surgery, colon and rectal surgery, cardiothoracic surgery, facial plastic surgery, head and neck surgery, 

hand surgery (plastic surgery), hand surgery (surgery), critical care (neurological surgery), neurological surgery, pediatric 

surgery (neurology), pediatric surgery, plastic surgery, surgical oncology, thoracic surgery, and transplant surgery. 

Nonsurgical specialties	 Allergy, addiction medicine, addiction psychiatry, allergy and immunology, allergy and immunology/diagnostic laboratory 

immunology, bronchoesophageal medicine, clinical genetics, clinical biochemical genetics, clinical cytogenetics, clinical 

molecular genetics, critical care medicine, dermatological immunology/diagnostic laboratory immunology, diabetes, 

emergency medicine, endocinology, sports medicine (emergency medicine), medical toxicology (emergency medicine), 

gastroenterology, general preventive medicine, hematology, hepatology, hematology/oncology, cardiac electrophysiology, 

infectious diseases, immunology, legal medicine, medical management, medical genetics, nephrology, nutrition, 

occupational medicine, medical oncology, clinical pharmacology, pulmonary critical care medicine, pediatric emergency 

medicine (emergency medicine) public health and general preventive medicine, pediatric/diagnostic laboratory 

immunology, palliative medicine, physical medicine and rehabilitation, pain medicine, medical toxicology (preventive 

medicine), pulmonary diseases, rheumatology, spinal cord injury, sleep medicine, and undersea medicine. 

conditions require immediate care and 

that is staffed 24 hours a day. If an ED 

provided emergency services in different 

areas of the hospital, all of these areas 

were selected with certainty into the 

sample. Off-site emergency departments 

that are open less than 24 hours are 

included if staffed by the hospital’s 

emergency department. 

Hospital—All hospitals with 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. Excludes 

Federal hospitals, hospital units of 

institutions, and hospitals with less than 

six beds staffed for patient use. 

Injury-related visit—A visit is 

considered related to an injury if ‘‘yes’’ 

was checked on the Patient Record form 

in response to the question, ‘‘Is this visit 

injury related?’’ or if any of the 

following information was provided on 

the form—place of injury, cause of 

injury, an injury-related reason for visit, 

or a nature of injury diagnosis. 

Office—An office is the space identified 

by a physician as a location for his or 

her ambulatory practice. Offices 

customarily include consultation, 

examination, or treatment spaces that 

patients associate with the particular 

physician. 

Office-based physician—A physician is 

a duly licensed doctor of medicine 

(M.D.) or doctor of osteopathy (D.O.) 

who is currently in office-based practice 

and who spends some time caring for 

ambulatory patients. Excluded from 

NAMCS are physicians who are hospital 

based; who specialize in anesthesiology, 

pathology, or radiology; who are 

federally employed; who treat only 

institutionalized patients; or who are 

employed full time by an institution and 

spend no time seeing ambulatory 

patients. 

Outpatient department—Hospital 

facility where nonurgent and ambulatory 

medical care is provided under the 

supervision of a physician. 

Visit—For NAMCS, a visit is a direct 

personal exchange between an 

ambulatory patient and a physician or a 

staff member working under the 

physician’s supervision, for the purpose 

of seeking care and rendering personal 

health services. Excluded from NAMCS 

are visits where medical care was not 

provided, such as visits made to drop off 

specimens, pay bills, make 

appointments, and walkouts. For 

NHAMCS, a visit is a direct, personal 

exchange between a patient and a 

physician or other health care provider 

working under the physician’s 

supervision for the purpose of seeking 

care and receiving personal health 

services.