Number 346 + August 26, 2004

National Ambulatory Medical Care Survey:

2002 Summary

by David A. Woodwell and Donald K. Cherry, M.S., Division of Health Care Statistics

Abstract

Objective—This report describes ambulatory care visits made to physician 

offices in the United States. Statistics are presented on selected characteristics of the 

physician’s practice, the patient, and the visit. This report also highlights visits to 

primary care specialties. 

Methods—The data presented in this report were collected from the 2002 

National Ambulatory Medical Care Survey (NAMCS). NAMCS is a part of the 

ambulatory care component of the National Health Care Survey that measures 

health care utilization across various types of providers. NAMCS is a national 

probability sample survey of visits to office-based physicians in the United States. 

Sample data are weighted to produce annual national estimates. Selected trends 

from 1992, 1993, 1995, and 1997 are also presented. 

Results—During 2002, an estimated 890 million visits were made to physician 

offices in the United States, an overall rate of 314.4 visits per 100 persons. From 

1992 through 2002, the visit rate for persons 45 years of age and over increased by 

14%, from 407.3 to 465.8 visits per 100 persons. The visit rate to physician offices 

in metropolitan statistical areas (MSAs) (337.3 visits per 100 persons) was 

significantly larger than the rate in non-MSAs (221.9 visits per 100 persons). For 

one-half of all office visits, regardless of specialty, physicians indicated they were 

the patient’s primary care physician (PCP). Of the visits to physicians other than the 

patient’s PCP, about one-third (31.1 percent) were referrals. New patients, 

representing 12.1 percent of the visits in 2002, are down 18% since 1992. Primary 

care specialists provided 90 percent of all preventive care visits. Essential 

hypertension, acute upper respiratory infection, diabetes mellitus, and arthropathies 

were the leading illness-related primary diagnoses. There were an estimated 104.0 

million injury-related visits in 2002, or 36.7 visits per 100 persons. On average, 2.3 

medications were ordered or provided at each office visit with any mention of a 

medication. The leading therapeutic class for drugs mentioned at office visits 

included nonsteroidal anti-inflammatory drugs (NSAIDs) (4.9 mentions per 100 

visits) and antidepressants (4.5 mentions per 100 visits). Of primary care specialists, 

25.8 percent reported not accepting new patients who are Medicaid enrollees. 

Keywords: ambulatory care c physician office care c diagnoses c injury c

medications c ICD–9–CM c primary care 

Introduction

The National Ambulatory Medical 

Care Survey (NAMCS), which began in 

1973, collects data on the utilization of 

ambulatory medical care services 

provided by office-based physicians. It 

was conducted annually until 1981, 

again in 1985, and resumed an annual 

schedule in 1989. The NAMCS is 

complemented by the National Hospital 

Ambulatory Medical Care Survey 

(NHAMCS), which was inaugurated in 

1992 to expand the scope of data 

collection to the medical services 

provided by hospital outpatient and 

emergency departments. Together, 

NAMCS and NHAMCS data provide an 

important tool for tracking ambulatory 

health care utilization in the United 

States. The NAMCS and NHAMCS are 

part of the National Health Care Survey 

(NHCS), which measures health care 

utilization across various types of 

providers. More information about the 

NHCS can be found at the National 

Center for Health Statistics (NCHS) 

Web site: www.cdc.gov/nchs/nhcs.htm. 

More information on the 2002 

NHAMCS annual summaries (hospital 

outpatient and emergency departments) 

is available (1,2). A separate report 

combining NAMCS and NHAMCS data 

provides a comprehensive picture of 

ambulatory health care utilization (3). It 

shows that 80 percent of ambulatory 

U.S. DEPARTMENT OF HEALTH AND HUMAN SERVICES


Centers for Disease Control and Prevention


National Center for Health Statistics

2 Advance Data No. 346 + August 26, 2004

care delivered by non-Federal physicians 

is provided in office-based practices. 

Hospital ambulatory patients are known 

to differ from office patients in certain 

demographic and medical characteristics. 

This report presents national annual 

estimates of physician office visits for 

2002. Physician practice, patient, and 

visit characteristics are described. A 

special section is presented this year on 

visits to primary care specialists, and 

additional information is also presented 

throughout the report. 

Data Highlights

Office visit estimates

+ In 2002, 890.0 million visits were 

made to physician offices, or about 

314.4 visits per 100 persons. Of these 

visits, 62.7 percent were made to 

primary care specialists, 19.9 percent 

to surgical specialists, and the 

remaining 17.3 percent to medical 

specialists. 

+ From 1992 through 2002, the visit 

rate for persons 45 years of age and 

over increased by 14%, from 407.3 to 

465.8 visits per 100 persons. 

+ The visit rate for white persons 

(334.6 visits per 100 persons) was 

higher than for black or AfricanAmerican persons (252.9 visits per 

100 persons) or Asians (229.3 visits 

per 100 persons). 

+ Private insurance was the most 

frequently expected source of 

payment, accounting for 59.0 percent 

of all visits, and government sources 

combined (Medicare and Medicaid 

and/or State Children’s Health 

Insurance Program (SCHIP)) 

accounted for 28.6 percent of visits. 

+ From 1992 through 2002, the percent 

of visits by patients with private 

insurance increased by 79%, and the 

percent of visits where there was no 

third-party payer decreased by 77%. 

+ Of visits made to office-based 

physicians, 13.9 percent were referred 

for the current visit. 

+ There were 104 million injury visits 

to office-based physicians in 2002. 

The visit rate for injuries increased 

with patient age, resulting in a rate of 

63.3 visits per 100 persons for 

patients 65 years of age and over. 

White persons had a significantly 

greater rate of injury visits than did 

black or African-American persons 

(39.6 versus 25.1 visits per 100 

persons). Fifty percent were to 

primary care specialists. 

Services provided

+ Although the rate of preventive care 

visits was higher for females than for 

males, there were no race differences 

observed. Ten percent of preventive 

care visits were made to specialists. 

+ Diagnostic and screening services 

were ordered or provided at 

84.9 percent of visits, counseling 

and/or education and/or therapeutic 

services were ordered or provided at 

44.7 percent of visits, and surgical 

procedures were ordered or provided 

at 9.1 percent of visits. An estimated 

69.8 million surgical procedures were 

ordered, scheduled, or performed 

during office visits. Approximately 

45 percent of the surgical procedures 

mentioned at visits were performed in 

the office. 

+ About 1.3 billion drugs were 

prescribed or provided at 64.8 percent 

of office visits. Although the percent 

of visits with any drug mention did 

not change, the average drug mention 

rate increased by 25% from 1992 to 

2002. This was driven by a 41% 

increase in visits with multiple drugs 

prescribed since 1992. 

+ Overall, the drug mention rate in 

2002 was similar to 2001, but varied 

by physician specialty (60.7 versus 

307.8 mentions per 100 visits). The 

drug mention rate for obstetrics/ 

gynecology (Ob/Gyn) physicians 

increased 48% from 2001, driven 

mostly by increases in contraceptives 

and vitamins. 

+ The top three therapeutic classes, 

NSAIDs, antidepressants, and 

antihistamines, increased significantly 

from 1995. Antidepressants increased 

48% during this period due to the 

increases in the drug mention rate for 

all ages. From 1995 through 2002, 

the drug mention rate at visits by 

children under 18 years of age rose 

124%. 

+ A physician was seen during most 

office visits (95.1 percent). During 

approximately 25 percent of the visits 

a medical/nursing assistant was seen. 

Visits to primary care

specialists

+ The majority of the 890 million office 

visits were to primary care specialists 

(62.7 percent) and of these visits most 

were to the patient’s PCP 

(76.2 percent). 

+ Approximately 40 percent of the 

visits to primary care specialists were 

for acute problems, followed by 

30 percent for chronic conditions. Ten 

percent were injury-related visits. 

+ Of the 558 million visits to primary 

care specialists in 2002, 70.6 percent 

included at least one medication 

ordered, supplied, administered, or 

continued. Vaccines accounted for 

almost 6 percent of the drug 

mentions. 

+ Half of the primary care visits 

resulted in a disposition to return for 

an appointment. 

Physician-level estimates

+ In 2002, office-based physicians 

reported an average of 77 office 

visits, 14 hospital visits, 14 telephone 

consultations, 1.3 house calls, and 0.4 

e-mail consultations during their last 

full week of practice. 

+ Approximately three-fourths of 

office-based physicians own or are 

part owner of their practice 

(72.7 percent). A greater percent of 

primary care specialists were 

employees compared with surgical or 

medical specialists (28.2 percent 

versus 16.2 and 17.0 percent, 

respectively). Two-thirds of primary 

care specialists work in group 

practices. 

+ Of primary care specialists, 

71.8 percent reported that they would 

accept new Medicare patients, a 

significantly lower percent than 

surgical specialists (96.4 percent). 

Similarly, 67.4 percent of primary 

care specialists reported that they 

would accept new Medicaid patients, 
Advance Data No. 346 + August 26, 2004 3

significantly lower than for surgical 

specialists (80.0 percent). 

Methods

The data presented in this report are 

from the 2002 NAMCS, a national 

probability sample survey conducted by 

the Centers for Disease Control and 

Prevention’s Division of Health Care 

Statistics of the National Center for 

Health Statistics. The survey was 

conducted from December 31, 2001, 

through December 30, 2002. The target 

universe of the NAMCS includes visits 

made in the United States to the offices 

of non-federally employed physicians 

(excluding those in the specialties of 

anesthesiology, radiology, and 

pathology) who were classified by the 

American Medical Association (AMA) 

and the American Osteopathic 

Association (AOA) as ‘‘office-based, 

patient care.’’ Visits to private, 

nonhospital-based clinics and health 

maintenance organizations (HMOs) were 

within the scope of the survey, but those 

that occurred in federally operated 

facilities and hospital-based outpatient 

departments were not. Telephone 

contacts and visits made outside the 

physician’s office were also excluded. 

The NAMCS utilizes a multistage 

probability sample design involving 

samples of primary sampling units 

(PSUs), physician practices within 

PSUs, and patient visits within 

physician practices. The PSUs are 

counties, groups of counties, county 

equivalents (such as parishes or 

independent cities), or towns and 

townships for some PSUs in New 

England. A sample of physicians was 

selected from the master files of the 

AMA and the AOA; 2,095 were in 

scope (eligible to participate in the 

survey). Sample physicians were asked 

to complete Patient Record forms (see 

figure I) for a systematic random sample 

of approximately 30 office visits 

occurring during a randomly assigned 

1-week reporting period. The weighted 

response rate for in-scope physicians 

was 71.1 percent, and a total of 28,738 

Patient Record forms were completed. 

The ‘‘Technical Notes’’ at the end of 

this report provide more information on independently keyed and coded. Coding 

characteristics of nonresponding error rates ranged between 0.1 and 

physicians. 1.1 percent for various survey items. 

Because the estimates presented in Several of the tables in this report 

this report are based on a sample rather present rates of physician office visits 

than on the entire universe of office per population. The population figures 

visits, they are subject to sampling used in calculating these rates are based 

variability. The ‘‘Technical Notes’’ on the U.S. Census Bureau’s monthly 

include an explanation of the sampling postcensal estimates of the civilian 

errors with guidelines for judging the noninstitutional population of the United 

precision of the estimates and States as of July 1, 2002. These 

information on physician and item population estimates are based on 

nonresponse. The standard errors are postcensal estimates from Census 2000 

calculated using Taylor series and are available from the Census 

approximations in SUDAAN, which Bureau. See the ‘‘Technical Notes’’ for 

take into account the complex sample more information about the effects of 

design of the NAMCS (4). Data on the change from 1990-based to 2000-

physician office utilization rates from based denominators on trends in 

1992 through 2002 and selected trends population rates. Estimates presented in 

by patient age are also presented. A the tables and figures for specific race 

weighted least-squares regression categories reflect visits where only a 

analysis was used to determine the single race was reported. See ‘‘Technical 

significance of trends at the 0.05 level. Notes’’ for more detail on race 

The U.S. Census Bureau was estimates. 

responsible for data collection. Data 

processing operations and medical Results

coding were performed by Constella 

Group, Inc., Durham, North Carolina. Results are presented separately for 

As part of the quality assurance office visit estimates and physician 

procedure, a 10-percent quality control practice estimates. 

sample of survey records was 

Figure 1. Trends in rate of visits to physician offices by persons 45 years of age and over:

United States, 1995–2002
4 Advance Data No. 346 + August 26, 2004

Office visit estimates

There were an estimated 890.0 

million visits to office-based physicians 

in 2002, about 314.4 visits per 100 

persons. Although the population of the 

United States increased by 13% since 

1992, the number of visits to physician 

offices increased by 17% (5). Visit rates 

for age groups 45 years and over 

increased by 20% since 1995 (figure 1). 

Selected characteristics of the encounter 

pertaining to the physician’s practice, 

the patient, and the visit are described 

later in this report. Estimates of 

physician practices and associated 

characteristics based on the induction 

interview are presented at the end of the 

report. 

Office practice characteristics—The 

distribution of office visits according to 

physician specialty is presented in 

table 1 and figure 2. About one-quarter 

of all visits were to general and family 

practice physicians with an additional 

39.0 percent of visits to physicians 

specializing in internal medicine, 

pediatrics, and Ob/Gyn. Of all the office 

visits made in 2002, about 6 out of 

every 10 were to physicians in primary 

care specialties (62.7 percent) as defined 

in table IV of the ‘‘Technical Notes.’’ 

Throughout this report, the terms ‘‘visits 

to primary care specialists/specialties’’ 

Figure 2. Percent distribution of office visits by physician specialty: United States, 2002

Figure 3. Annual rate of visits to office-based physicians by patient’s age and sex:

United States, 2002

and ‘‘primary care visits’’ will be used 

interchangeably. Surgical and medical 

specialties accounted for 19.9 and 

17.3 percent of visits, respectively. 

Table 1 also shows that doctors of 

osteopathy received 65.4 million visits 

during 2002, or 7.3 percent of all office 

visits. Visits to osteopathic physicians 

occurred at a rate of 23.1 visits per 100 

persons. Visits according to geographic 

region and metropolitan status are also 

displayed in table 1. The visit rates were 

similar for each of the geographic 

regions, except the visit rate for the 

Northeast region (385.2 visits per 100 

persons) was significantly higher than 

the rate in the West (289.4 visits per 

100 persons). The visit rate to physician 

offices located in MSAs (337.3 visits 

per 100 persons) was significantly larger 

than the rate observed in non-MSAs 

(221.9 visits per 100 persons). 

Additional information on the 

physician’s practice has been collected 

annually in the NAMCS through the 

Physician Induction Interview (PII) 

form. The PII is used to obtain basic 

information on the practice, establish the 

visit sampling rate, and record the final 

disposition of the interview. In 2002, 

selected survey items on the physician 

and physician’s practice, including 

employment status, ownership, practice 

size, and office type, were weighted and 

edited to produce national estimates of 

office visits by these characteristics. 

These data demonstrate the type of 

practices to which visits are being made 

and are displayed in table 2. Overall, 

86.2 percent of the visits were to 

physicians who owned the practice 

themselves or owned it with a group of 

other physicians. The majority of office 

visits (64.7 percent) were made to 

physicians engaged in group practice. 

More than one-half of all visits were to 

physicians in practices with 2–9 

physicians (53.0 percent) compared with 

11.3 percent of visits to large practices 

with 10 or more physicians. 

Significantly more visits to group 

practices were characterized as singlespecialty practices (41.2 percent) 

compared with multispecialty practices 

(23.5 percent). 

Patient characteristics—Office 

visits by patient’s age, sex, and race are 

shown in table 3. As in previous years, 
Advance Data No. 346 + August 26, 2004 5

Figure 4. Annual rate of visits to office-based physicians by patient’s age and race:

United States, 2002

females made the majority of office 

visits during 2002. The percent of visits 

was higher for females compared with 

males across all age groups except for 

persons under 15 years of age. Sex 

differences were also observed for visit 

rates between 15 and 64 years of age. 

For those patients 15 years of age and 

over, as age increased, the number of 

patient visits rose. The positive effect of 

age on physician office utilization is 

shown in figures 3 and 4. 

White persons represented 81 

percent of the U.S. civilian 

noninstitutional population in 2002, but 

made 86.1 percent of all physician office 

visits. Overall, the visit rate for white 

persons (334.6 visits per 100 persons) 

was significantly higher than for black 

or African-American persons (252.9 

visits per 100 persons), Asians (229.3 

visits per 100 persons), and American 

Indian or Alaska Native (82.9 visits per 

100 persons). Historically, visit rates for 

black or African-American persons to 

physician offices tend to be lower than 

those for white persons. However, 

differences in visit rates by race can 

vary by type of health care setting 

utilized. Data presented in the 2002 

NHAMCS outpatient department 

summary indicate that the visit rate for 

black or African-American persons (52.8 

visits per 100 persons) was higher than 

for white persons (26.8 visits per 100 

persons) (1). Visits made by patients 

identified as Asian accounted for 

3.0 percent of all physician office visits, 

and patients who were Native Hawaiian 

or other Pacific Islander and American 

Indian or Alaska Native each accounted 

for about 1 percent of the office visits. 

Patients who claimed multiple race 

categories also accounted for 1 percent 

of office visits. 

Continuity of care—Continuity of 

care is a goal of health care achieved 

through an interdisciplinary process 

involving patients, families, health care 

professionals, and providers in the 

management of a coordinated plan of 

care. It may involve multiple 

professionals from many different 

disciplines within multiple systems. The 

NAMCS collects information on aspects 

of care (e.g., whether the physician was 

the patient’s primary care physician 

(PCP), whether the visit was a referral, 

and the number of visits within the past 

12 months) that can help describe where 

the visit fits within the continuum of 

care for the patient. 

In 2002, 50.4 percent of physician 

office visits were to the patient’s PCP; 

44.0 percent were to physicians other 

than the patient’s PCP, and at 5.6 

percent of visits it was unknown if the 

physician was the patients PCP (table 4). 

Visits by new patients were more likely 

to be referrals than visits made by 

established patients (46.3 percent versus 

9.3 percent). 

Table 5 describes visits to PCPs and 

non-PCPs in terms of referral status and 

physician specialty. It should be noted 

that not all visits to the patient’s PCP 

were to physicians who specialize in 

primary care. Among visits to the 

patients’ PCP, 5.1 percent were to 

physicians specializing in either surgical 

or medical specialties (data not shown). 

Among visits to non-PCPs, the 

specialties with visits most frequently 

referred by other physicians are 

neurology (55.2 percent), urology 

(50.9 percent), and orthopedic surgery 

(45.5 percent). More than one-half of 

visits to Ob/Gyns, ophthalmologists, 

dermatologists, and psychiatrists were 

self referrals. 

Table 6 shows the prior visit status, 

whether the care for the patient was 

shared by other physicians, and the 

episode of care. As shown, established 

patients accounted for 86.7 percent of 

office visits. Three-quarters of office 

visits (75.6 percent) were made by 

established patients who had at least one 

previous visit in the last 12 months and 

more specifically, 22.7 percent had six 

or more visits in the previous 12 

months. New patients accounted for 

12.1 percent of visits representing an 

18% decrease from 1992. Medical and 

surgical care specialists were more 

likely to share care with other 

physicians (28.4 percent and 

31.6 percent, respectively) compared 

with primary care specialists 

(18.4 percent). 

Primary expected source of

payment—Private insurance was cited 

most frequently as the primary expected 

source of payment (59.0 percent of 

visits). Government sources combined 

(Medicare and Medicaid and/or SCHIP 

accounted for 28.6 percent of office 

visits, most of which were Medicare 

(table 7). From 1992 through 2002, 

private insurance increased 79% (from 

32.9 percent to 59.0 percent) and visits 

with no third-party payer (as defined by 

self-pay and no charge/charity) 

decreased by 77% (from 20.7 to 

4.7 percent) (data not shown). Primary 

care specialists saw a significantly 

greater percent of visits that were paid 
6 Advance Data No. 346 + August 26, 2004

Figure 5. Percent distribution of office visits by primary expected source of payment,

according to patient age: United States, 2002

(10.0 percent), and symptoms referable 

to the eyes and ears, which accounted 

for 5.5 percent of all visits (table 8). 

The 20 most frequently mentioned 

principal reasons for visit, representing 

42.5 percent of all visits, are shown in 

table 9. General medical examination 

was the most frequently mentioned 

reason for visit at 7.3 percent of all 

office visits, and cough was the most 

frequently mentioned reason regarding 

an illness or injury (3.2 percent). All but 

two of the reasons for office visits in 

2002 were listed in the 20 most 

frequently mentioned reasons in 2001, 

albeit in a different order. It should be 

noted that estimates differing in ranked 

where private insurance (63.3 percent) 

was the primary expected source of 

payment than did surgical specialtists 

(52.4 percent) or medical specialtists 

(51.4 percent). Visits that had a primary 

expected source of payment of either 

Medicare or Medicaid/SCHIP 

represented a significantly greater 

percent of visits to surgical specialists 

compared with primary care specialists 

(34.5 percent versus 26.3 percent) (data 

not shown). 

As expected, source of payment 

varied by patient age (figure 5). Private 

insurance was the primary expected 

source of payment at a majority of visits 

by patients under age 65 years and only 

represented 17.8 percent of visits by 

persons 65 years of age and over. 

Three-quarters of visits by elderly 

patients listed Medicare as the primary 

source of payment at office visits 

(74.2 percent). Private insurance 

accounted for a larger share of visits in 

MSAs as opposed to non-MSAs (60.8 

versus 48.3 percent, respectively) (data 

not shown). Medicare and Medicaid 

accounted for a greater share of visits in 

non-MSAs as opposed to MSAs (27.5 

and 13.4 percent in non-MSAs versus 

20.1 and 6.6 percent in MSAs). 

Patient’s principal reason for

visit—The principal reason for visit is 

the main complaint, symptom, or reason 

listed for why the patient came to the 

physician’s office. Up to three reasons 

for visit were coded according to A

Reason for Visit Classification for

Ambulatory Care (RVC) (6). The RVC 

is a classification scheme developed by 

NCHS that has been used for over 20 

years to code patients’ complaints or 

reasons for seeking care. It is divided 

into eight modules or groups of reasons 

as shown in table 8 and includes all the 

reasons for which patients see their 

physicians. This includes symptoms, 

followup for prior diagnoses, routine 

examinations and screening, treatment 

for conditions and operations, various 

therapies, and injuries. Also included are 

visits to receive test results and to fulfill 

third-party requirements for a physical 

examination, such as for employment or 

a driver’s license. The symptoms 

module is further divided into symptoms 

that refer to specific body systems, such 

as digestive or respiratory. Each reason 

is assigned a three- or four-digit 

classification code (e.g., S845-

‘‘Symptoms of skin mole’’ is further 

detailed to S845.1- ‘‘Change in size and 

color’’ and S845.2- ‘‘Bleeding mole’’). 

In 2002, one-half of all visits were 

made for reasons classified as 

symptoms. Some of the more prominent 

symptoms included respiratory 

(10.5 percent), musculoskeletal 

order may not be significantly different 

from each other. 

The major reason for this visit 

provides a better picture of the general 

nature of the office visit—whether for 

an acute problem; routine visit for a 

chronic problem; visit for a flare-up of a 

chronic problem; pre- or post-surgery 

visit; or for preventive care, including 

routine prenatal examinations, general 

medical examinations, well-baby 

examinations, screening, and 

examinations for insurance purposes. 

The major reason for visit item differs 

from the principal reason for visit item 

in that the former represents the 

physician’s rather than the patient’s 

perspective of the major reason why the 

patient sought care. Acute problems 

comprised 36.4 percent of the visits, and 

routine chronic problems accounted for 

29.7 percent (table 10). Approximately 

16.3 percent of all visits were for 

preventive care. A higher percent of 

visits by females were for preventive 

care compared with visits by males. The 

percent of visits for acute and 

preventive care declined with patient 

age, whereas the percent of visits for 

chronic conditions increased with patient 

age. 

Table 11 describes the frequency of 

preventive care visits by patient, visit, 

and physician characteristics. The 

female visit rate for preventive care was 

significantly greater than the rate for 

males (66.9 visits per 100 females 

versus 34.6 visits per 100 males). These 

sex differences reflect, in part, the fact 

that preventive care includes prenatal 

examinations that usually include 
Advance Data No. 346 + August 26, 2004 7

multiple visits within 1 year. In 2002, 

18.1 percent of the preventive visits 

made by females also included a visit 

made for normal pregnancy (any 

diagnosis coded V22) (data not shown). 

However, even after removing visits for 

normal pregnancy, females still had a 

higher visit rate (54.8 visits per 100 

females) compared with males (34.6 

visits per 100 males) (data not shown). 

There was no difference in visit rates 

for preventive care by sex among 

children under 15 years of age or among 

the elderly (65 years old and over). 

Uninsured persons (as measured by 

self-pay and charity visits) had a much 

lower preventive care visit rate 

compared with persons with private or 

public health insurance, placing them at 

a potential disadvantage for disease 

prevention and early diagnosis. 

Primary diagnosis—Physicians 

were asked to record the primary 

diagnosis or problem associated with the 

patient’s most important reason for the 

current visit and any other significant 

current diagnoses. Up to three diagnoses 

were coded according to the 

International Classification of Diseases,

9th Revision, Clinical Modification

(ICD–9–CM) (7). Table 12 shows office 

visits by the physician’s primary 

diagnosis using the major disease 

categories specified in the ICD–9–CM. 

The supplementary classification, used 

for diagnoses that are not classifiable to 

injury or illness (for example, general 

medical examination, routine prenatal 

examination, and health supervision of 

an infant or child), accounted for 

16.4 percent of all office visits. Diseases 

of the respiratory system (12.6 percent), 

diseases of the circulatory system 

(9.0 percent), and diseases of the 

nervous system and sense organs 

(8.9 percent) were also prominent 

categories on the list. 

The 20 most frequently reported 

primary diagnoses for 2002, accounting 

for 42.8 percent of all physician office 

visits, are shown in table 13. The 

categories in this table are also based on 

the ICD–9–CM. The leading illness 

diagnoses include essential hypertension, 

acute upper respiratory infections 

(excluding pharyngitis), diabetes 

mellitus, arthropathies and related 

disorders, and spinal disorders. 

Injury-related visits—Although 

there is a separate item or checkbox on 

the Patient Record form to indicate 

whether the visit was for an injury, 

poisoning, or adverse medical treatment, 

sometimes an injury reason for visit is 

specified or an injury diagnosis is 

rendered without the injury item being 

checked. Therefore, the visit is counted 

as an injury visit and the injury 

checkbox is coded ‘‘Yes’’ if any of the 

three reasons for visit were in the injury 

module or any of the three diagnoses 

were in the injury or poisoning chapter 

of the ICD–9–CM. This provides a 

better indicator that the visit involves an 

injury than using the reason for visit 

module, ICD–9–CM injury diagnosis, or 

the unedited injury item alone. A more 

detailed discussion is documented 

elsewhere (8). 

There were an estimated 104.0 

million injury- or poisoning-related 

office visits in 2002, representing 

11.7 percent of all visits and yielding a 

rate of 36.7 visits per 100 persons 

(table 14). The injury-related visit rate 

increased significantly with patient age. 

The rate for patients aged 75 years and 

over (63.3 visits per 100 persons) was 

approximately double that of the three 

age groups under 45 years of age. The 

injury-related visit rate for females was 

not significantly different from the rate 

for males nor were there differences 

between the female and male rates when 

compared by each of the specific age 

groups. The overall injury-related visit 

rate for white persons (39.6 visits per 

100 persons) was higher than the 

injury-related rate for black or AfricanAmerican persons (25.1 visits per 100 

persons) and persons of ‘‘other’’ race 

(23.6 visits per 100 persons). Small 

sample sizes preclude analysis by age 

within some race groups. Half of the 

injury visits were to primary care 

specialists (50.5 percent) with no 

significant difference between white and 

black or African-American persons (data 

not shown). Further information on 

injury visits to physician offices is 

available on the public-use file, 

including external cause-of-injury codes 

(E-codes) and a narrative of the cause of 

injury. 

Office visits by intent and 

mechanism of the first-listed E-codes 

are shown in table 15. Up to three 

external causes of injury were coded 

according to the ‘‘Supplementary 

Classification of External Causes of 

Injury and Poisoning’’ in the ICD–9– 

CM (7). Cause of injury was not 

recorded for 38.0 percent of injuryrelated visits, so the observed 

distribution could change with more 

complete reporting. For a detailed 

description of the cause-of-injury codes, 

refer to table III in the ‘‘Technical 

Notes.’’ 

Diagnostic and screening

services—Table 16 displays 

examinations and diagnostic and 

screening services ordered or provided 

by physicians during office visits. At 

least one such service was ordered or 

provided at 84.9 percent of office visits, 

resulting in approximately 204 services 

per 100 visits. Information on diagnostic 

services was missing for 0.9 percent of 

visits. 

The most frequently occurring 

diagnostic service was a general medical 

examination; one-half of all visits 

(49.7 percent) included a general 

medical examination. Some of the most 

frequent laboratory tests ordered 

included urinalysis (9.6 percent), 

complete blood count (8.8 percent), and 

cholesterol (5.2 percent) (table 16). 

Imaging was ordered or provided at 

10.9 percent of visits; the majority of 

imaging services were x-rays. Visits by 

females were more likely to have 

imaging performed compared with visits 

by males, a difference due mostly to 

mammographies. The percent of visits 

that had any imaging ordered or 

provided increased significantly from 

3.9 percent in 1993 to 4.5 percent in 

2002 (data not shown). 

Counseling/education and

therapeutic services—Therapeutic and 

preventive services (not including 

medication therapy, which was reported 

separately) were ordered or provided at 

44.7 percent of all office visits during 

2002, resulting in approximately 68 

services per 100 visits. The most 

frequent counseling or education 

provided at office visits related to diet 

and/or nutrition (14.3 percent) and 

exercise (10.0 percent) (table 17). 

Females were just as likely as males to 

have any one of the 10 listed 
8 Advance Data No. 346 + August 26, 2004

counseling, education, or therapeutic 

services ordered or provided at an office 

visit. Information regarding therapeutic 

services was missing for 2.1 percent of 

visits. 

Procedures—In item 8 of the 

Patient Record form, physicians were 

instructed to record up to two surgical 

procedures ordered, scheduled, or 

performed at the visit. Item 6, 

‘‘Diagnostic and screening services,’’ 

included two open-ended ‘‘other’’ 

categories in addition to the checkbox 

categories. After analyzing data from the 

‘‘other’’ categories and the surgery 

checkbox (item 8), it was discovered 

that the same procedure was being 

recorded in different places on different 

records. Table 18 presents data from 

item 8 and the open-ended responses to 

item 6 as coded to ICD–9–CM volume 

3 in the range of 01–86 (7). During 

2002, there were an estimated 69.8 

million surgical procedures ordered or 

performed during visits to office-based 

physicians resulting in approximately 10 

surgical procedures per 100 visits. About 

9.1 percent of visits had such procedures 

ordered or performed (up by 72% since 

1992) (data not shown). About 

45 percent of surgical procedures were 

performed in the office. 

Medication therapy—NAMCS 

respondents were instructed to record all 

new or continued medications ordered, 

supplied, or administered at the visit. 

This included prescription and 

nonprescription preparations, 

immunizations, desensitizing agents, and 

anesthetics. Up to six medications, 

referred to in this survey as drug 

mentions, were coded according to a 

classification system developed at 

NCHS. A report describing the method 

and instruments used to collect and 

process drug information is available 

(9). As used in the NAMCS, the term 

‘‘drug’’ is interchangeable with the term 

‘‘medication,’’ and the term 

‘‘prescribing’’ is used broadly to mean 

ordering or providing any medication, 

whether prescription or over the counter. 

Visits with one or more drug mentions 

are termed ‘‘drug visits’’ in the 

NAMCS. Data on medication therapy 

are in tables 19–23. 

Medication therapy was reported at 

577.1 million office visits, accounting 

Figure 6. Trends in drug mention rates for NSAIDs, antidepressants, and antihistamines at

physician office visits: United States, 1995–2002

for 64.8 percent of all office visits 

(table 19). During 2002, there were 

about 1.3 billion drugs mentioned, 

resulting in an overall drug mention rate 

of 151.4 mentions per 100 visits. Data 

on drug visits and drug mentions by 

physician specialty are shown in table 

20. The percent of visits with at least 

one drug mention ranged from 

82.6 percent for psychiatrists to 

28.1 percent for general surgeons. The 

overall drug mention rate was similar to 

last year’s; however, the drug mention 

rate for Ob/Gyn physicians increased 

48% from 55.5 mentions per 100 visits 

in 2001 to 82.4 mentions per 100 visits 

in 2002 (data not shown). Increases in 

Ob/Gyn drug mention rates were driven 

by a 24% increase in the percent of 

visits with any mention of drugs (from 

39.6 to 48.9 percent) and a 60% 

increase in the mention of 

contraceptives and vitamins. The drug 

mention rate for other physician 

specialties was not significantly different 

from 2002. 

Table 21 presents the 20 most 

frequent therapeutic classes of drug 

mentions by four-digit therapeutic 

classification codes used in the National

Drug Code (NDC) Directory, 1995 

edition. Drugs may have more than one 

therapeutic application, and up to three 

therapeutic drug classes are recorded for 

each drug (10). Prior to 2002, a drug 

was classified under its primary 

therapeutic use and data were presented 

for two-digit therapeutic classification 

codes. Beginning in 2002, drug data are 

shown for up to three therapeutic 

subclassifications at the four-digit level. 

In 2002, the leading drug subclasses 

were NSAIDs (4.9 percent), followed by 

antidepressants (4.5 percent), 

antihistamines (4.3 percent), 

antiasthmatics or bronchodilators (4.0 

percent), and vaccines or antisera (4.0 

percent). 

Examining the top three therapeutic 

drug classes further, figure 6 shows that 

between 1995 and 2002 the drug 

mention rates per 100 visits for 

NSAIDs, antidepressants, and 

antihistamines have all increased 

significantly (10%, 48%, and 35%, 

respectively). Increases in drug mention 

rates by therapeutic class can be driven 

by numerous factors including how new 

drugs are classified by the Food and 

Drug Administration (FDA) and the 

level of marketing these drugs receive. 

For example, increases in NSAIDs are 

directly attributed to the new subclass of 

drugs called COX-2 inhibitors. Sales of 

Celebrex and Vioxx have grown briskly 

since their approval as priority new 

molecular entities (NMEs) and from 

intensive marketing aimed at both 

consumers and physicians (11). Since 

1999, the number of NAMCS drug 

mentions for Celebrex increased 44% 

and since 2000 Vioxx mentions 
Advance Data No. 346 + August 26, 2004 9

Figure 7. Trends in antidepressant drug mention rates at physician office visits by

patient’s age: United States, 1995–2002

increased 17%. Direct-to-consumer Many factors have also been 

(DTC) marketing, along with the attributed to the rise in antidepressant 

creation of nonsedating second- and drug mention rates. Figure 7 shows 

third-generation drugs, represent two trends from 1995 through 2002 among 

major reasons for the rise in the four age groups: under 18 years, 18–44 

antihistamine mention rate since 1995 years, 45–64 years, and 65 years and 

(12,13). The leading antihistamine over. The rate of visits with 

mentioned in 2002 was Zyrtec, which antidepressants mentioned significantly 

was approved by the FDA in 1996. increased for all age groups, with visits 

Other leading antihistamines include by younger patients showing the largest 

Allegra and Claritin. rate increase from 1995. For patients 

under 18 years of age, the number of 

Figure 8. Trends in the drug mention rates for antidepressants by subclass at physician

office visits: United States, 1992–2002

mentions per 100 visits increased 124%; 

for patients aged 18–44 years, the rate 

increased 57%; the rate increased 39% 

for patients aged 45–64 years; and 

increased 29% for seniors aged 65 years 

of age and over. Observed increases in 

NAMCS antidepressant mention rates 

were not surprising given the fact that 

from 1987 through 1997, more 

individuals were being treated for 

depression. Treatments typically 

involved more psychotropic medications 

and comparatively less psychotherapy, 

and physicians became more involved in 

the treatment of depression versus other 

mental health professionals (14). 

Research has suggested that an increase 

in antidepressant prescribing has been 

directly related to the introduction of the 

new subclass of antidepressants called 

selective serotonin reuptake inhibitors 

(SSRIs) (15). Compared with all other 

classes of antidepressants, SSRIs now 

represent the preferred class of drugs 

used by physicians in treating patients 

with major depression. These drugs are 

especially attractive alternatives to older, 

once popular, tricyclic antidepressants 

(TCAs) because they typically possess 

fewer adverse side effects, have a 

reduced risk of suicide-related deaths, 

involve simpler dosing patterns, and 

have equivalent antidepressant 

effectiveness as TCAs (16). Figure 8 

demonstrates this increase in SSRIs and 

decrease of TCAs. Since 1992, SSRIs 

have increased from 0.7 drug mentions 

per 100 visits to 4.1 drug mentions per 

100 visits in 2002, an increase of 

approximately 500%. TCAs declined 

from 1.5 drug mentions per 100 visits in 

1992 to 0.8 drug mentions per 100 visits 

in 2002, a decrease of approximately 

47%. 

The 20 most frequently used 

generic substances for 2002 are shown 

in table 22. Drug products containing 

more than one ingredient (combination 

products) are included in the data for 

each ingredient. For example, 

acetaminophen with codeine is included 

in both the count for acetaminophen and 

the count for codeine. Compared with 

the 19 other generic substances and 

consistent with previous years, 

acetaminophen was most frequently 

used in drugs ordered or provided by 

the physician at office visits, occurring 
10 Advance Data No. 346 + August 26, 2004

in 3.4 percent of drug mentions. This nurse practitioners, and/or midwives,


was followed by amoxicillin, were seen at 3.1 percent of physician


hydrochlorothiazide, albuterol, and office visits.


aspirin. Visit disposition—Staff were asked


Table 23 presents the 20 to record all visit dispositions and 

medications most frequently mentioned instructed that multiple responses could 

by physicians in the NAMCS according be coded for this item. For 6 out of 10 

to the name written on the Patient visits (60.4 percent), patients were told 

Record form. This could be a brand to return to the office by appointment 

name, generic name, or therapeutic (table 25). ‘‘Return if needed’’ and ‘‘no 

effect. Lipitor accounted for 18.8 followup planned’’ were indicated at 

million mentions (1.4 percent of the 27.4 and 8.5 percent of visits, 

total) and was followed by albuterol, respectively. Patients were referred to 

amoxicillin, Synthroid, and Lasix. other physicians at 7.3 percent of visits. 

Fifteen of these drugs were among the Time spent with physician—Data on 

top 20 drug entry names mentioned in the duration of office visits are 

2001. presented in tables 26 and 27. Time 

Providers seen—In this item, staff spent in face-to-face contact between the 

were asked to check all of the providers physician and the patient is estimated 

seen during the visit. Overall, and recorded by the physician. It 

95.1 percent of visits were attended by a excludes time spent waiting to see the 

physician (table 24). Medical and/or physician, time spent receiving care 

nursing assistants were seen at from someone other than the physician 

27.3 percent of office visits. Midlevel without the presence of the physician, 

providers, such as physician assistants, and time spent by the physician in 

Figure 9. Characteristics of visits to office-based physicians, by specialty: United States,

2002

reviewing patient records and/or test 

results. In cases where the patient 

received care from a nonphysician 

member of the physician’s staff, but did 

not actually see the physician during the 

visit, the duration was recorded as ‘‘0’’ 

minutes. 

In 2002, 88.3 percent of office visits 

with face-to-face contact between the 

physician and patient had a duration 

between 6 and 30 minutes (table 26). At 

43.8 million visits, or 4.9 percent, there 

was no face-to-face contact between the 

physician and patient. Table 27 shows 

the mean duration for all visits at which 

a physician was seen as well as the 

mean duration at each quartile by 

physician specialty. Overall, the mean 

time spent with a physician was 18.4 

minutes. The visit duration for 

psychiatrists had the largest variability 

(a difference of 28.4 minutes between 

the third and first quartiles). 

Visits to primary care

specialists—In 2002, the NAMCS 

sampled an additional 150 primary care 

specialty physicians in order to provide 

more analytical power for understanding 

primary care. Detailed information on 

the sample and definitions of primary 

care physicians can be found in the 

‘‘Technical Notes.’’ This section 

highlights visits to primary care 

specialists. 

Visits to primary care specialties 

accounted for 62.7 percent of the 890 

million visits to office-based physicians 

in 2002 (table 1). Approximately 

three-fourths of these visits were to the 

patient’s designated PCP. Approximately 

8 percent of visits to primary care 

specialties were by new patients, and 

most established patients had seen their 

physician in the last 12 months 

(79.5 percent) (table 6). The percent of 

visits made to primary care specialists 

where the patient was responsible for 

the payment was significantly less than 

at visits made to medical specialists 

(3.8 percent versus 8.0 percent) (Data 

not shown). The role of preventive care 

in primary care specialists can be seen 

from the last two columns in table 11. 

Approximately 9 out of 10 preventive 

care visits were to primary care 

specialists; however, receipt of 

preventive care from primary care 

specialists decreases with age. 
Advance Data No. 346 + August 26, 2004 11

Characteristics of visits to primary care specialists:

+ Accounted for 62.7 percent of all visits in 2002, with 75 percent to the 

patient’s designated primary care provider. 

+ Major reason for visit to primary care specialists: 

o Acute conditions—41.5 percent 

o Chronic conditions—29.6 percent 

o Preventive care—23.3 percent 

+ Top five illness-related diagnoses are: 

o Hypertension—7.8 percent 

o Acute upper respiratory infections (excluding pharyngitis)—5.1 percent 

o Diabetes mellitus—3.1 percent 

o Otitis media—2.4 percent 

o Arthropathies—2.1 percent 

+ Injury visits accounted for 9.4 percent of all visits to primary care specialists. 

+ Common services ordered or provided: 

o General medical examination—60.8 percent 

o Blood pressure check—60.1 percent 

o Urinalysis—12.8 percent 

o Complete blood count (CBC)—10.9 percent 

o Diet/nutrition counseling—19.3 percent 

o Exercise counseling—12.2 percent 

+ Top therapeutic drug classes were: 

o Vaccines/antisera—5.7 percent of drug mentions 

o NSAIDs—5.5 percent of drug mentions 

o Antihistamines—4.8 percent of drug mentions 

o Antidepressants—4.0 percent of drug mentions 

o Antihypertensives—3.9 percent of drug mentions 

o Antiasthmatics—3.8 percent of drug mentions 

+ Disposition of visit: 

o Return for an appointment—53.4 percent 

o Return if needed—33.4 percent 

o Referred to another physician—8.0 percent 

+ Average face-to-face duration—17.4 minutes. 

Figure 9 summarizes characteristics 

of office visits by physician specialty 

type and contrasts primary care with 

surgical and medical specialties. Primary 

care specialists managed 165 problems 

per 100 visits. They ordered or provided 

235 diagnostic and screening services, 

165 medications, 76 counseling/ 

education services, and 5 surgical 

procedures per 100 visits. Acute 

conditions accounted for 41.5 percent of 

visits to primary care specialties 

followed by 29.6 percent for chronic 

conditions and 23.3 percent for 

preventive care (see textbox). 

The leading illness-related primary 

diagnoses at primary care specialty 

visits included essential hypertension 

(7.8 percent), acute upper respiratory 

infection (excluding pharyngitis) (5.1 

percent), diabetes mellitus (3.1 percent), 

otitis media (2.4 percent), and 

arthropathies (2.1 percent). Normal 

pregnancy visits accounted for 3.1 

percent of primary diagnoses at these 

visits. 

About 1 in 10 visits were for an 

injury. Six of ten visits to primary care 

specialists (60.8 percent) had a general 

medical examination, a significantly 

higher percentage than for visits to 

surgical specialists (23.4 percent) and 

medical specialists (39.8 percent). 

Overall, a blood pressure check occurred 

at 48.1 percent of all visits (table 16); 

however, blood pressure checks varied 

by physician specialty. Although primary 

care specialists indicated that they 

checked the patient’s blood pressure at 

three-fifths of visits, medical specialists 

reported blood pressure checks at 

two-fifths of visits, and surgical 

specialists performed such checks at 

one-fifth of visits (data not shown). 

Drugs were prescribed at 70.6 

percent of the visits to primary care 

physicians. The leading therapeutic 

classes prescribed include vaccines (5.7 

percent of drug mentions), NSAIDs (5.5 

percent), antihistamines (4.8 percent), 

antidepressants (4.0 percent), 

antihypertensives (3.9 percent), and 

antiasthmatics (3.8 percent). 

Patients at primary care visits were 

told to return for an appointment at 53.4 

percent of visits, told to return if needed 

at 33.4 percent of visits, and referred to 

another physician at 8.0 percent of 

visits. The average duration of primary 

care visits was 17.4 minutes. 

Physician-level estimates

The NAMCS provides information 

on characteristics of physician offices as 

well as information about the frequency 

of office visits, the characteristics of 

patients, diagnoses rendered, and 

services provided at the visit. In the 

Physician Induction Interview (PII), 

participating physicians were asked 

several questions about their practice 

such as other kinds of patient encounters 

(e.g., telephone, e-mail), involvement 

with managed care contracts, and 

willingness to accept new patients. The 

data were weighted to provide annual 

estimates for all non-Federal, officebased physicians primarily engaged in 

patient care. Table 28 provides national 

estimates for office-based physicians in 

2002. There were an estimated 308,023 

office-based physicians in practice in 

any given week in the United States 

(SE=8,149). This estimate excludes 

physicians in the specialties of 

radiology, anesthesiology, or pathology. 

One-half of these physicians 

(50.2 percent) were in primary care 

specialties, 25.5 percent were in surgical 

specialties, and 24.3 percent in medical 

specialties. 

Although similar to the visit level 

data shown in table 1, table 28 shows 
12 Advance Data No. 346 + August 26, 2004

that about one-third of the physicians 

were in solo practices with the 

remaining in either single- or 

multispecialty-group practices (41.0 and 

24.7 percent, respectively). The majority 

of physicians were the owners or part 

owners of their practices (72.7 percent). 

Primary care specialists were employees 

a greater percent of the time compared 

with surgical or medical specialists 

(28.2 percent versus 16.2 and 

17.0 percent, respectively). 

Another practice characteristic 

collected in the PII is the number of 

encounters the physician makes during 

his/her last full week of practice. These 

include: office visits, home visits, 

hospital visits, telephone consultations, 

and internet/e-mail consultations. 

Table 28 presents the percent of 

physicians who had at least one of each 

of the various encounters during their 

last full week of practice and, for those 

physicians with at least one, the mean 

number for each of the encounters. For 

example, 19.1 percent of primary care 

specialists reported having at least one 

home visit during their last full week of 

practice. Of these physicians the mean 

number of reported home visits was 

11.7. Primary care specialists reported 

more telephone contacts (26.3) than 

surgical specialists (11.5) or medical 

specialists (15.7). Medical specialists 

made more hospital visits (34.1) than 

did surgical (17.6) or primary care 

specialists (17.0). Not shown in table 28 

is the mean number of each of the 

weekly encounters for all physicians: 77 

office visits, 14 hospital visits, 14 

telephone contacts, 1.3 house calls, and 

0.4 internet/e-mail consults. 

The NAMCS PII asks physicians 

about their willingness to accept new 

patients. Ninety-five percent of the 

physicians said they would accept new 

patients, (table 28). Figure 10 shows the 

percent of physicians who said they 

would not accept new patients by 

payment source. Approximately 

37.7 percent of office-based physicians 

did not accept new charity cases (as 

defined by the no charge check box), 

23.5 percent did not accept new 

Medicaid cases, and 13.8 percent did not 

accept new Medicare cases. Primary 

care specialists were more likely to 

refuse new Medicare cases 

Figure 10. Percent of office-based physicians who do not accept new patients who use

selected payment methods: United States, 2002

(21.1 percent) compared with either 

surgical specialists (2.0 percent) or 

medical specialists (12.0 percent) and 

more likely to refuse Medicaid cases 

(25.8 percent) compared with surgical 

specialists (17.6 percent) (data not 

shown). 

A greater percent of physician 

practices used electronic billing records 

than electronic medical records 

(74.4 percent versus 17.3 percent) due to 

the requirement by Medicare and 

Medicaid. 

Additional information about 

physician office utilization is available 

from the NCHS Ambulatory Health 

Care Web site: 

http://www.cdc.gov/nchs/about/ 

major/ahcd/ahcd1.htm. Individual-year 

reports and public-use data files are 

available for download from the Web 

site. Data from the 2002 NAMCS will 

also be available on a public-use data 

tape and CD-ROM. These and other 

products can be obtained by contacting 

the NCHS Ambulatory Care Statistics 

Branch at (301) 458-4600. Queries 

regarding NAMCS data may be sent to 

NCHS via nchsquery@cdc.gov. 

References

1.	 Hing ES, Middleton, KR. National 

Hospital Ambulatory Medical Care 

Survey: 2002 outpatient department 

summary. Advance data from vital 

and health statistics; no 345. 

Hyattsville, Maryland: National 

Center for Health Statistics. 2003. 

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

ad345.pdf 

2.	 McCaig LF, Burt CW. National 

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Survey: 2002 emergency department 

summary. Advance data from vital 

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Hyattsville, Maryland: National 

Center for Health Statistics. 2003. 

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

ad340.pdf 

3.	 Burt CW, Schappert SM. Ambulatory 

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for Health Statistics. Vital Health 

Stat. 13(157). 2004. 

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SUDAAN user’s manual, release 8.0. 

Research Triangle Park, NC: 

Research Triangle Institute. 2002. 

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Medical Care Survey: 1992 

summary. Advance data from vital 

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Hyattsville, Maryland: National 

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

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6.	 Schneider D, Appleton L, McLemore 

T. A reason for visit classification for 

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Modification, 6th ed., Washington:

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Elinson L, Tanielian T, Pincus HA.

National trends in the outpatient

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SC, Olfson M, Zarin DA, Thompson

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14 Advance Data No. 346 + August 26, 2004

Table 1. Number, percent distribution, and annual rate of office visits with corresponding standard errors, by selected physician practice

characteristics: United States, 2002

Number of 

Number of Standard Standard visits per Standard 

visits in error in Percent error of 100 persons error 

Physician practice characteristics thousands thousands distribution percent per year1,2 of rate 

All visits ..................................... 889,980 28,110 100.0 . . . 314.4 9.9 

Physician specialty 

General and family practice ......................... 215,466 13,117 24.2 1.2 76.1 4.6 

Internal medicine ................................ 156,692 14,734 17.6 1.4 55.4 5.2 

Pediatrics .................................... 120,018 8,213 13.5 0.9 3

198.1 13.6 

Obstetrics and gynecology .......................... 70,324 6,410 7.9 0.7 4

60.9 5.6 

Ophthalmology ................................. 49,937 5,568 5.6 0.6 17.6 2.0 

Orthopedic surgery............................... 38,028 5,027 4.3 0.6 13.4 1.8 

Dermatology................................... 32,227 3,819 3.6 0.4 11.4 1.3 

Psychiatry .................................... 21,659 2,979 2.4 0.3 7.7 1.1 

Cardiovascular diseases ........................... 20,822 2,554 2.3 0.3 7.4 0.9 

Urology ...................................... 17,133 1,891 1.9 0.2 6.1 0.7 

Otolaryngology ................................. 17,080 1,954 1.9 0.2 6.0 0.7 

General surgery ................................ 17,000 2,154 1.9 0.2 6.0 0.8 

Neurology .................................... 9,622 900 1.1 0.1 3.4 0.3 

All other specialties .............................. 103,974 9,200 11.7 1.0 36.7 3.2 

Professional identity 

Doctor of medicine ............................... 824,595 27,653 92.7 0.7 291.3 9.8 

Doctor of osteopathy ............................. 65,385 6,636 7.3 0.7 23.1 2.3 

Specialty type5 

Primary care .................................. 558,402 22,198 62.7 1.3 197.3 7.8 

Surgical ..................................... 177,397 10,576 19.9 1.0 62.7 3.7 

Medical ...................................... 154,181 10,895 17.3 1.2 54.5 3.8 

Geographic region 

Northeast .................................... 205,668 14,023 23.1 1.4 385.2 26.3 

Midwest ..................................... 196,749 11,632 22.1 1.2 307.0 18.1 

South ....................................... 300,665 19,173 33.8 1.6 297.7 19.0 

West ....................................... 186,898 9,744 21.0 1.1 289.4 15.1 

Metropolitan status 

MSA6 ....................................... 765,191 27,191 86.0 1.5 338.4 12.0 

Non-MSA6 .................................... 124,790 13,689 14.0 1.5 222.6 24.4 

. . . Category not applicable. 1Visit rates for age, sex, race, and region are based on the July 1, 2002, set of estimates of the civilian noninstitutional population of the United States as developed by the Population Division, 

U.S. Census Bureau. These population estimates reflect Census 2000 data and are available from the U.S Census Bureau. See the ‘‘Technical Notes’’ for more details. 22002 population estimates of metropolitan statistical area status are based on Census 2000 data and were obtained through the Office of Research and Methodology and Division of Health 

Interview Statistics, National Center for Health Statistics. 3The population used for the rate is based on visits by children under 15 years of age. 4The population used for the rate is based on visits by females 15 years old and over. 5Specialty type is defined in table IV of the ‘‘Technical Notes.’’ 6MSA is metropolitan statistical area. 

NOTE: Numbers may not add to totals because of rounding. 
Advance Data No. 346 + August 26, 2004 15 

Table 2. Number and percent distribution of office visits with corresponding standard errors, by selected physician practice

characteristics: United States, 2002

Number of Standard Standard 

visits in error in Percent error of 

Physician office characteristics thousands thousands distribution percent 

All visits ........................................ 889,980 28,110 100.0 . . . 

Employment status 

Owner ......................................... 664,121 29,206 74.6 1.9 

Employee ....................................... 189,987 16,404 21.3 1.8 

Contractor ....................................... 35,873 6,758 4.0 0.8 

Ownership 

Physician/group.................................... 767,468 27,423 86.2 1.6 

Other health care corporation ........................... 42,497 7,606 4.8 0.8 

Other hospital ..................................... 33,188 6,504 3.7 0.7 

Medical/academic health center .......................... *19,794 6,632 *2.2 0.7 

HMO1 .......................................... 14,885 4,024 1.7 0.5 

Other2 ......................................... 12,149 3,566 1.4 0.4 

Practice size 

Solo ........................................... 313,795 20,044 35.3 1.9 

2–4 ........................................... 290,632 18,256 32.7 1.8 

5–9 ........................................... 180,825 15,433 20.3 1.5 

10–39.......................................... 80,796 10,825 9.1 1.2 

40 or more....................................... *19,505 6,579 *2.2 0.7 

Blank .......................................... *4,428 1,833 *0.5 0.2 

Type of practice 

Single-specialty group ................................ 366,676 19,869 41.2 2.0 

Multispecialty group ................................. 209,510 18,294 23.5 1.8 

Solo ........................................... 313,795 20,044 35.3 1.9 

Office type 

Private practice .................................... 817,154 28,662 91.8 1.2 

Clinic/urgicenter ................................... 46,380 9,827 5.2 1.1 

Other3 ......................................... 26,447 4,739 3.0 0.5 

. . . Category not applicable. 

* Figure does not meet standard of reliability or precision.

1HMO is health maintenance organization.

2Other includes owners such as local government (State, county, or city) and charitable organizations.

3Other includes the following office types: HMO, non-Federal government clinic, mental health center, federally qualified health center, and facility practice plan.

NOTE: Numbers may not add to totals because of rounding.
16 Advance Data No. 346 + August 26, 2004

Table 3. Number, percent distribution, and annual rate of office visits with corresponding standard errors, by patient’s age, sex, and

race: United States, 2002

Number 

of visits 

Number of Standard Standard per 100 Standard 

visits in error in Percent error of persons error of 

Patient’s age, sex, and race thousands thousands distribution percent per year1 rate 

All visits ................................... 889,980 28,110 100.0 . . . 314.4 9.9 

Age 

Under 15 years ............................... 159,235 8,449 17.9 0.8 262.8 13.9 

15–24 years ............................... 71,865 3,605 8.1 0.4 181.9 9.1 

25–44 years ............................... 192,359 7,978 21.6 0.6 232.2 9.6 

45–64 years ............................... 242,142 9,915 27.2 0.6 365.8 15.0 

65–74 years ............................... 109,331 5,361 12.3 0.4 606.4 29.7 

75 years and over ............................ 115,049 6,066 12.9 0.5 722.2 38.1 

Sex and age 

Female .................................... 529,075 17,025 59.4 0.6 364.9 11.7 

Under 15 years ............................. 76,382 4,287 8.6 0.4 258.1 14.5 

15–24 years ............................... 44,909 2,494 5.0 0.3 228.8 12.7 

25–44 years ............................... 128,743 5,836 14.5 0.5 306.3 13.9 

45–64 years ............................... 144,205 6,164 16.2 0.4 422.7 18.1 

65–74 years ............................... 61,819 3,254 6.9 0.3 628.1 33.1 

75 years and over ............................ 73,017 4,305 8.2 0.4 745.7 44.0 

Male ..................................... 360,905 13,295 40.6 0.6 261.4 9.6 

Under 15 years ............................. 82,853 4,556 9.3 0.5 267.2 14.7 

15–24 years ............................... 26,956 1,989 3.0 0.2 135.6 10.0 

25–44 years ............................... 63,616 3,650 7.1 0.3 155.9 8.9 

45–64 years ............................... 97,937 4,811 11.0 0.4 305.3 15.0 

65–74 years ............................... 47,512 2,686 5.3 0.2 580.2 32.8 

75 years and over ............................ 42,032 2,353 4.7 0.2 684.6 38.3 

Race and age2 

White ..................................... 766,096 26,574 86.1 1.0 334.6 11.6 

Under 15 years ............................. 131,023 7,208 14.7 0.7 282.9 15.6 

15–24 years ............................... 61,012 3,297 6.9 0.3 197.5 10.7 

25–44 years ............................... 164,890 7,534 18.5 0.6 248.3 11.3 

45–64 years ............................... 211,162 9,145 23.7 0.6 380.7 16.5 

65–74 years ............................... 95,465 5,311 10.7 0.5 611.4 34.0 

75 years and over ............................ 102,544 5,504 11.5 0.5 720.1 38.7 

Black or African American ........................ 89,455 8,108 10.1 0.9 252.9 22.9 

Under 15 years ............................. 19,867 2,695 2.2 0.3 209.4 28.4 

15–24 years ............................... 8,071 985 0.9 0.1 142.0 17.3 

25–44 years ............................... 18,750 1,862 2.1 0.2 181.2 18.0 

45–64 years ............................... 22,496 2,592 2.5 0.3 319.2 36.8 

65–74 years ............................... 10,733 2,659 1.2 0.3 658.8 163.2 

75 years and over ............................ 9,538 2,595 1.1 0.3 811.7 220.8 

All other races2 

Asian ..................................... 26,341 3,851 3.0 0.4 229.3 33.5 

Native Hawaiian or other Pacific Islander ............... 3,430 708 0.4 0.1 721.7 148.9 

American Indian or Alaska Native.................... 2,237 473 0.3 0.1 82.9 17.5 

Multiple races ................................ *2,421 749 *0.3 0.1 *58.6 18.1 

. . . Category not applicable. 

*Figure does not meet standard of reliability or precision. 1Visit rates for age, sex, and race are based on the July 1, 2002, set of estimates of the civilian noninstitutional population of the United States as developed by the Population Division, U.S. 

Census Bureau. These population estimates reflect Census 2000 data and are available from the U.S. Census Bureau. See ‘‘Technical Notes’’ for more details. 2The race groups, white, black or African American, Asian, Native Hawaiian or other Pacific Islander, American Indian or Alaska Native, and multiple races, include persons of Hispanic and not 

Hispanic origin. Persons of Hispanic origin may be of any race. Starting with data year 1999, race-specific estimates have been tabulated according to 1997 Standards for Federal Data on Race 

and Ethnicity and are not strictly comparable with estimates for earlier years. However, the percent of visit records with multiple races indicated is small and lower than what is typically found for 

self-reported race. See ‘‘Technical Notes’’ for more details. 

NOTE: Numbers may not add to totals because of rounding. 
Advance Data No. 346 + August 26, 2004 17 

Table 4. Number and percent distribution of office visits with corresponding standard errors, by selected visit characterstics, according

to prior-visit status: United States, 2002

Prior-visit status 

All Established New Unknown/ 

Primary care physician and referral status visits patient patient blank 

Number of visits in thousands 

All visits ..................................... 889,980 771,679 108,049 10,252 

Visit to PCP1 .................................. 448,679 427,647 19,030 2,002 

Visit to non-PCP1 ............................... 391,742 308,530 81,124 2,089 

Referred by other physician ........................ 122,011 71,517 50,070 424 

Not referred by other physician ...................... 212,410 189,294 22,330 786 

Unknown if referred ............................. 57,320 47,718 8,724 *879 

Unknown if PCP1 visit ............................. 49,559 35,503 7,895 *6,161 

Standard error in thousands 

All visits ..................................... 28,110 24,906 5,929 2,965 

Visit to PCP1 .................................. 20,737 19,745 1,898 415 

Visit to non-PCP1 ............................... 17,135 13,771 5,289 509 

Referred by other physician ........................ 7,312 4,710 3,452 108 

Not referred by other physician ...................... 12,968 11,290 3,289 202 

Unknown if referred ............................. 5,989 5,606 1,104 392 

Unknown if PCP1 visit ............................. 7,547 5,931 1,299 2,893 

Percent distribution 

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

Visit to PCP1 .................................. 50.4 55.4 17.6 *19.5 

Visit to non-PCP1 ............................... 44.0 40.0 75.1 *20.4 

Referred by other physician ........................ 13.7 9.3 46.3 *4.1 

Not referred by other physician ...................... 23.9 24.5 20.7 *7.7 

Unknown if referred ............................. 6.4 6.2 8.1 *8.6 

Unknown if PCP1 visit ............................. 5.6 4.6 7.3 60.1 

Standard error of percent 

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

Visit to PCP1 .................................. 1.5 1.5 1.6 6.6 

Visit to non-PCP1 ............................... 1.5 1.5 2.0 7.0 

Referred by other physician ........................ 0.7 0.6 2.4 1.5 

Not referred by other physician ...................... 1.3 1.3 2.5 2.8 

Unknown if referred ............................. 0.7 0.7 0.9 4.2 

Unknown if PCP1 visit ............................. 0.8 0.8 1.2 11.8 

* Figure does not meet standard of reliability or precision.

. . . Category not applicable.

1PCP is patient’s primary care physician or provider.

NOTE: Numbers may not add to totals because of rounding. 
18 Advance Data No. 346 + August 26, 2004

Table 5. Percent distribution of office visits with corresponding standard errors by physician specialty, according to primary care

physician and referral status: United States 2002

Visit to non-PCP2 

Referred Not referred 

by other 

Physican specialty Total physician

Visit to 

PCP1 

by other 

physician 

Unknown 

if referred 

Unknown if 

PCP1 visit 

Percent distribution 

All visits ................................... 100.0 50.4 13.7 23.9 6.4 5.6 

General and family practice ....................... 100.0 84.1 *2.8 6.5 1.2 5.5 

Internal medicine .............................. 100.0 82.3 2.9 *6.0 *1.9 *7.0 

Pediatrics .................................. 100.0 88.2 2.0 5.5 2.5 1.9 

Obstetrics and gynecology ........................ 100.0 15.3 10.0 54.0 6.5 14.1 

Ophthalmology ............................... 100.0 *2.0 20.7 61.7 11.9 *3.7 

Orthopedic surgery............................. 100.0 *5.3 45.5 36.9 9.8 * 

Dermatology................................. 100.0 * 18.9 58.7 18.6 *3.7 

Cardiovascular diseases ......................... 100.0 * 15.9 64.6 14.3 *4.7 

Psychiatry .................................. 100.0 13.4 40.2 40.6 4.9 * 

General surgery .............................. 100.0 *8.1 41.0 40.2 9.0 * 

Otolaryngology ............................... 100.0 * 39.8 42.4 13.9 3.3 

Urology .................................... 100.0 *3.8 50.9 33.9 10.2 * 

Neurology .................................. 100.0 *2.6 55.2 29.6 10.3 2.2 

All other specialties ............................ 100.0 13.1 27.7 34.2 17.1 *7.9 

Standard error of percent 

All visits ................................... . . . 1.5 0.7 1.3 0.7 0.8 

General and family practice ....................... . . . 2.2 0.9 1.4 0.3 1.1 

Internal medicine .............................. . . . 3.8 0.8 2.2 1.0 2.5 

Pediatrics .................................. . . . 1.8 0.6 1.3 0.7 0.4 

Obstetrics and gynecology ........................ . . . 3.3 2.2 5.1 1.9 3.7 

Ophthalmology ............................... . . . 1.0 4.1 5.0 2.8 1.8 

Orthopedic surgery............................. . . . 2.0 5.1 4.9 2.2 . . . 

Dermatology................................. . . . . . . 3.1 5.4 5.0 1.8 

Cardiovascular diseases ......................... . . . . . . 4.3 6.0 3.6 1.7 

Psychiatry .................................. . . . 4.0 5.8 5.6 1.0 . . . 

General surgery .............................. . . . 3.0 5.1 4.6 2.2 . . . 

Otolaryngology ............................... . . . . . . 3.9 4.5 2.7 1.0 

Urology .................................... . . . 2.6 4.5 4.4 3.0 . . . 

Neurology .................................. . . . 0.9 3.8 3.6 2.5 0.5 

All other specialties ............................ . . . 3.1 3.8 4.2 4.2 3.9 

* Figure does not meet standard of reliability or precision.

. . . Category not applicable.

1PCP is patient’s primary care physician or provider.

2Referral status only asked for visits to nonprimary care physicians or providers.

NOTE: Numbers may not add to totals because of rounding. 
Advance Data No. 346 + August 26, 2004 19 

Table 6. Number and percent distribution of office visits with corresponding standard errors, by continuity-of-care visit characteristics

according to specialty type: United States, 2002

Specialty type Specialty type 

All Primary All Primary 

Continuity-of-care visit characteristics specialties care Surgical Medical specialties care Surgical Medical 

Number of visits in thousands Standard error in thousands 

All visits ................................. 889,980 558,402 177,397 154,181 28,110 22,198 10,576 10,895 

Prior-visit status and number of visits in last 12 months 

Established patient........................... 771,679 508,721 139,308 123,651 24,906 20,557 8,546 9,262 

None .................................. 56,080 33,204 13,640 9,236 3,797 3,225 1,320 1,103 

1–2 visits ............................... 245,048 151,762 57,049 36,237 10,461 8,043 3,958 3,510 

3–5 visits ............................... 225,822 155,650 37,519 32,654 9,944 8,643 2,781 3,232 

6 or more visits ........................... 201,998 136,529 24,844 40,625 10,909 8,578 2,356 5,939 

Unknown ............................... 42,731 31,576 6,255 *4,898 5,138 4,672 1,197 1,695 

New patient ............................... 108,049 42,481 36,507 29,061 5,929 3,940 2,882 2,795 

Unknown if patient previously seen................. 10,252 *7,200 1,582 1,470 2,965 2,926 278 

Do other physicians share care for this problem? 

Yes .................................... 202,393 102,662 55,996 43,736 11,317 8,019 5,298 4,721 

No ..................................... 570,326 384,892 104,432 81,002 22,255 18,556 7,939 8,133 

Unknown/blank ............................. 117,261 70,848 16,969 29,444 12,155 9,626 2,106 6,778 

Episode of care 

Initial visit for problem ......................... 273,910 189,092 47,167 37,651 10,771 9,294 3,384 3,494 

Followup visits for problem ...................... 401,767 196,012 103,529 102,227 17,117 12,353 6,580 8,131 

Unknown/blank ............................. 69,452 43,046 17,384 9,022 5,318 4,491 2,237 1,196 

Not applicable (preventive care visit)1 ............... 144,851 130,253 9,316 5,282 8,045 7,988 1,254 1,056 

Percent distribution Standard error of percent 

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

Prior-visit status and number of visits in last 12 months 

Established patient........................... 86.7 91.1 78.5 80.2 0.6 0.8 1.1 1.4 

None .................................. 6.3 5.9 7.7 6.0 0.4 0.6 0.6 0.6 

1–2 visits ............................... 27.5 27.2 32.2 23.5 0.8 1.0 1.0 1.7 

3–5 visits ............................... 25.4 27.9 21.1 21.2 0.7 0.9 0.9 1.6 

6 or more visits ........................... 22.7 24.4 14.0 26.3 1.0 1.2 1.1 3.0 

Unknown ............................... 4.8 5.7 3.5 *3.2 0.6 0.8 0.7 1.1 

New patient ............................... 12.1 7.6 20.6 18.8 0.5 0.6 1.1 1.4 

Unknown if patient previously seen................. 1.2 *1.3 0.9 1.0 0.3 0.5 0.2 0.3 

Do other physicians share care for this problem? 

Yes .................................... 22.7 18.4 31.6 28.4 1.1 1.3 2.4 2.8 

No ..................................... 64.1 68.9 58.9 52.5 1.4 1.8 2.5 3.8 

Unknown/blank ............................. 13.2 12.7 9.6 19.1 1.3 1.6 1.1 4.0 

Episode of care 

Initial visit for problem ......................... 30.8 33.9 26.6 24.4 0.7 1.1 1.1 1.6 

Followup visits for problem ...................... 45.1 35.1 58.4 66.3 1.1 1.5 1.4 1.8 

Unknown/blank ............................. 7.8 7.7 9.8 5.9 0.6 0.8 1.1 0.7 

Not applicable (preventive care visit)1 ............... 16.3 23.3 5.3 3.4 0.8 1.1 0.6 0.6 

. . . Category not applicable. 

* Figure does not meet standard of reliability or precision.

1 Preventive care includes routine prenatal, general medical, well-baby, and screening or insurance examinations.

NOTE: Numbers may not add to totals because of rounding. 

404 
20 Advance Data No. 346 + August 26, 2004

Table 7. Number and percent distribution of office visits with corresponding standard errors, by primary expected source of payment:

United States, 2002

Number of Standard Standard 

visits in error in Percent error of 

Primary expected source of payment thousands thousands distribution percent 

All visits ........................................ 889,980 28,110 100.0 . . . 

Private insurance................................... 525,520 19,927 59.0 1.1 

Medicare ........................................ 188,207 9,642 21.1 0.8 

Medicaid/SCHIP1 ................................... 67,110 5,168 7.5 0.6 

Self-pay ........................................ 39,526 4,111 4.4 0.4 

Workers’ compensation ............................... 14,658 2,561 1.6 0.3 

No charge/charity .................................. 2,485 526 0.3 0.1 

Other .......................................... 21,456 4,258 2.4 0.5 

Unknown/blank .................................... 31,018 4,254 3.5 0.5 

. . . Category not applicable.

1SCHIP is State Children’s Health Insurance Program.

NOTE: Numbers may not add to totals because of rounding.

Table 8. Number and percent distribution of office visits with corresponding standard errors, by patient’s principal reason for visit:

United States, 2002

Number of Standard Standard 

visits in error in Percent error of 

Principal reason for visit and RVC code1 thousands thousands distribution percent 

All visits .................................................... 889,980 28,110 100.0 . . . 

Symptom module....................................... S001–S999 452,280 16,678 50.8 1.0 

General symptoms .................................... S001–S099 58,080 4,831 6.5 0.5 

Symptoms referable to psychological/mental disorders .............. S100–S199 26,279 2,009 3.0 0.2 

Symptoms referable to the nervous system (excluding sense organs) ..... S200–S259 22,687 1,496 2.5 0.1 

Symptoms referable to the cardiovascular/lymphatic system ........... S260–S299 4,476 661 0.5 0.1 

Symptoms referable to the eyes and ears ...................... S300–S399 48,703 3,311 5.5 0.3 

Symptoms referable to the respiratory system ................... S400–S499 93,529 5,654 10.5 0.5 

Symptoms referable to the digestive systems .................... S500–S639 35,136 2,354 3.9 0.2 

Symptoms referable to the genitourinary system .................. S640–S829 30,769 1,797 3.5 0.2 

Symptoms referable to the skin, hair, and nails ................... S830–S899 43,690 3,000 4.9 0.3 

Symptoms referable to the musculoskeletal system ................ S900–S999 88,933 6,360 10.0 0.6 

Disease module ....................................... D001–D999 100,526 5,838 11.3 0.6 

Diagnostic/screening and preventive module ...................... X100–X599 164,643 8,994 18.5 0.8 

Treatment module .......................................T100–T899 112,807 8,930 12.7 0.9 

Injuries and adverse effects module ............................ J001–J999 22,445 1,788 2.5 0.2 

Test results module ..................................... R100–R700 22,078 2,106 2.5 0.2 

Administrative module .................................... A100–A140 6,845 1,395 0.8 0.2 

Other2 ............................................. U990–U999 8,357 1,147 0.9 0.1 

. . . Category not applicable. 1Based on A Reason for Visit Classification for Ambulatory Care (RVC) (6). 2Includes problems and complaints not elsewhere classified, entries of ‘‘none,’’ blanks, and illegible entries. 

NOTE: Numbers may not add to totals because of rounding. 
tion of office visits with corresponding standard errors, by the 20 principal reasons for visit most frequently mentioned by patients,

ates, 2002

Patient’s sex 

Female2 Male3 

Number of Standard Standard Standard Standard 

visits in error in Percent error of Percent error of Percent error of 

d RVC code1 thousands thousands distribution percent distribution percent distribution percent 

................... 889,980 28,110 100.0 . . . 100.0 . . . 100.0 . . . 

................ X100 64,726 4,667 7.3 0.4 6.8 0.5 7.9 0.5 

................ T800 40,983 5,414 4.6 0.6 3.9 0.5 5.6 0.7 

................ S440 28,469 2,086 3.2 0.2 3.1 0.2 3.4 0.3 

................ T205 22,083 1,648 2.5 0.2 2.4 0.2 2.6 0.2 

................ X205 19,582 2,552 2.2 0.3 3.7 0.5 . . . . . . 

................ S455 18,515 1,535 2.1 0.2 2.2 0.2 2.0 0.2 

................ D510 17,195 2,315 1.9 0.3 2.0 0.4 1.8 0.2 

................ S925 14,803 1,611 1.7 0.2 1.7 0.2 1.7 0.2 

................ X105 14,293 1,440 1.6 0.2 1.4 0.2 1.9 0.2 

................ T115 14,076 1,638 1.6 0.2 1.6 0.2 1.6 0.2 

................ S545 13,547 1,406 1.5 0.2 1.7 0.2 1.2 0.2 

................ S355 13,160 1,127 1.5 0.1 1.4 0.1 1.5 0.2 

................ S905 12,902 1,298 1.4 0.1 1.4 0.1 1.6 0.2 

................ S305 12,897 1,663 1.4 0.2 1.4 0.2 1.5 0.2 ................ X320 12,630 2,096 1.4 0.2 1.5 0.3 1.3 0.2 

................ S010 12,258 1,248 1.4 0.1 1.2 0.1 1.7 0.2 

................ S400 12,149 1,570 1.4 0.2 1.2 0.2 1.5 0.2 

................ S860 11,887 1,061 1.3 0.1 1.2 0.1 1.6 0.2 

ble to body system) .... S050 *11,189 3,546 *1.3 0.4 *1.4 0.5 1.1 0.3 

................ D205 11,189 1,378 1.3 0.1 1.0 0.1 1.6 0.2 

................... 511,446 17,420 57.5 0.8 57.8 0.9 57.0 1.0 

ion. 

latory Care (RFV) (6). 

unding. 

Advance Data No. 346+ August 26, 2004 21
22 Advance Data No. 346 + August 26, 2004

Table 10. Number and percent distribution of office visits with corresponding standard errors by major reason for this visit, according to

patient’s age, sex, and race: United States, 2002

Major reason for visit 

Chronic Chronic 

Acute problem, problem, Pre- or Preventive Unknown/ 

Patient’s age, sex, and race Total problem routine flare-up post-surgery care1 blank 

Number of visits in thousands 

All visits ................................. 889,980 323,541 264,452 76,383 46,153 144,851 34,601 

Age 

Under 15 years ............................. 159,235 82,771 17,133 7,758 2,552 43,557 5,463 

15–24 years ............................... 71,865 32,191 13,004 4,906 2,957 15,872 2,934 

25–44 years ............................... 192,359 71,598 46,366 16,383 10,606 39,865 7,541 

45–64 years ............................... 242,142 77,842 88,022 25,908 13,211 27,316 9,844 

65–74 years ............................... 109,331 27,665 47,987 10,702 7,636 10,642 4,698 

75 years and over ........................... 115,049 31,474 51,941 10,726 9,191 7,598 4,120 

Sex 

Female .................................. 529,075 185,407 153,009 46,087 27,177 97,008 20,387 

Male ................................... 360,905 138,134 111,443 30,296 18,976 47,843 14,214 

Race2 

White ................................... 766,096 280,834 226,296 68,513 41,432 120,074 28,947 

Black ................................... 89,455 31,165 27,961 5,358 3,763 17,502 3,706 

Other ................................... 34,429 11,542 10,194 2,512 958 7,275 *1,948 

Standard error in thousands 

All visits ................................. 28,110 12,089 13,424 5,720 3,107 8,045 5,092 

Age 

Under 15 years ............................. 8,449 5,541 2,165 983 411 3,208 1,143 

15–24 years ............................... 3,605 1,960 1,700 701 408 1,664 683 

25–44 years ............................... 7,978 3,885 3,077 1,571 878 3,414 1,252 

45–64 years ............................... 9,915 3,664 5,037 2,507 1,106 2,446 1,699 

65–74 years ............................... 5,361 1,793 3,215 1,078 812 1,586 1,095 

75 years and over ........................... 6,066 2,078 3,957 1,009 1,034 1,084 821 

Sex 

Female .................................. 17,025 7,240 8,723 3,552 1,893 5,879 3,424 

Male ................................... 13,295 5,921 5,822 2,701 1,547 3,601 1,989 

Race2 

White ................................... 26,574 11,155 11,925 5,403 2,895 7,096 4,476 

Black ................................... 8,108 2,819 4,503 729 459 2,450 923 

Other ................................... 4,926 1,267 2,450 502 202 1,575 633 

Percent distribution 

All visits ................................. 100.0 36.4 29.7 8.6 5.2 16.3 3.9 

Age 

Under 15 years ............................. 100.0 52.0 10.8 4.9 1.6 27.4 3.4 

15–24 years ............................... 100.0 44.8 18.1 6.8 4.1 22.1 4.1 

25–44 years ............................... 100.0 37.2 24.1 8.5 5.5 20.7 3.9 

45–64 years ............................... 100.0 32.1 36.4 10.7 5.5 11.3 4.1 

65–74 years ............................... 100.0 25.3 43.9 9.8 7.0 9.7 4.3 

75 years and over ........................... 100.0 27.4 45.1 9.3 8.0 6.6 3.6 

Sex 

Female .................................. 100.0 35.0 28.9 8.7 5.1 18.3 3.9 

Male ................................... 100.0 38.3 30.9 8.4 5.3 13.3 3.9 

Race2 

White ................................... 100.0 36.7 29.5 8.9 5.4 15.7 3.8 

Black ................................... 100.0 34.8 31.3 6.0 4.2 19.6 4.1 

Other ................................... 100.0 33.5 29.6 7.3 2.8 21.1 *5.7 

See footnotes at end of table. 
Advance Data No. 346 + August 26, 2004 23 

Table 10. Number and percent distribution of office visits with corresponding standard errors by major reason for this visit, according to

patient’s age, sex, and race: United States, 2002—Con.

Major reason for visit 

Chronic Chronic 

Acute problem, problem, Pre- or Preventive Unknown/ 

Patient’s age, sex, and race Total problem routine flare-up post-surgery care1 blank 

Standard error of percent 

All visits ................................. . . . 0.8 1.1 0.5 0.3 0.8 0.6 

Age 

Under 15 years ............................. . . . 1.9 1.2 0.6 0.3 1.4 0.7 

15–24 years ............................... . . . 2.2 2.0 0.9 0.5 1.9 0.9 

25–44 years ............................... . . . 1.3 1.4 0.7 0.5 1.5 0.6 

45–64 years ............................... . . . 0.9 1.4 0.9 0.4 0.9 0.7 

65–74 years ............................... . . . 1.2 2.0 0.9 0.7 1.3 1.0 

75 years and over ........................... . . . 1.4 1.8 0.8 0.8 0.9 0.7 

Sex 

Female .................................. . . . 0.9 1.3 0.6 0.3 0.9 0.6 

Male ................................... . . . 1.0 1.2 0.6 0.4 0.8 0.5 

Race2 

White ................................... . . . 0.9 1.1 0.6 0.3 0.8 0.6 

Black ................................... . . . 2.6 3.2 0.8 0.6 1.9 0.9 

Other2 .................................. . . . 3.2 3.6 1.4 0.6 2.5 1.9 

* Figure does not meet standard of reliability or precision. 

. . . Category not applicable. 1Preventive care includes prenatal, general medical, well-baby, and screening or insurance examinations. 2Other race includes visits by Asians, Native Hawaiians or other Pacific Islanders, American Indians or Alaska Natives, and multiple races. All race categories include visits by persons of Hispanic 

and not Hispanic origin. Persons of Hispanic origin may be of any race. Starting with data year 1999, race-specific estimates have been tabulated according to 1997 Standards for Federal Data on 

Race and Ethnicity and are not strictly comparable with estimates for earlier years. However, the percent of visit records with multiple races indicated is small and lower than what is typically found 

for self-reported race. See ‘‘Technical Notes’’ for more details. 

NOTE: Numbers may not add to totals because of rounding. 
24 Advance Data No. 346 + August 26, 2004

Table 11. Number, percent distribution, and annual rate of preventive care office visits and percent of visits to primary care specialists

with corresponding standard errors, by selected patient and visit characteristics: United States, 2002

Number of 

Number of Standard Standard visits per Standard Percent of preventive Standard 

visits in error in Percent error of 100 persons error of care visits made to error of 

Patient and visit characteristics thousands thousands distribution percent per year1 rate primary care specialists percent 

All preventive care visits2.................. 144,851 8,045 100.0 . . . 51.2 2.8 89.9 1.2 

Age 

Under 15 years ........................ 43,557 3,208 30.1 2.0 71.9 5.3 95.8 1.6 

15–24 years .......................... 15,872 1,664 11.0 1.0 40.2 4.2 96.0 1.1 

25–44 years .......................... 39,865 3,414 27.5 1.6 48.1 4.1 94.2 1.1 

45–64 years .......................... 27,316 2,446 18.9 1.2 41.3 3.7 82.7 2.6 

65–74 years .......................... 10,642 1,586 7.3 0.9 59.0 8.8 74.3 4.8 

75 years and over ...................... 7,598 1,084 5.2 0.7 47.7 6.8 69.0 5.5 

Sex and age 

Female ............................. 97,008 5,879 67.0 1.7 66.9 4.1 91.6 1.2 

Under 15 years ...................... 21,106 1,618 14.6 1.0 71.3 5.5 95.2 1.9 

15–24 years ........................ 12,606 1,494 8.7 0.9 64.2 7.6 96.5 1.2 

25–44 years ........................ 34,003 3,133 23.5 1.6 80.9 7.5 95.6 1.2 

45–64 years ........................ 18,471 1,886 12.8 1.0 54.1 5.5 86.1 2.6 

65–74 years ........................ 5,853 735 4.0 0.4 59.5 7.5 77.7 4.2 

75 years and over ..................... 4,968 890 3.4 0.6 50.7 9.1 72.9 6.0 

Male .............................. 47,843 3,601 33.0 1.7 34.6 2.6 86.5 1.8 

Under 15 years ...................... 22,451 1,865 15.5 1.2 72.4 6.0 96.3 1.5 

15–24 years ........................ 3,266 427 2.3 0.3 16.4 2.1 94.0 2.4 

25–44 years ........................ 5,862 1,000 4.0 0.6 14.4 2.5 86.2 3.6 

45–64 years ........................ 8,844 1,140 6.1 0.7 27.6 3.6 75.6 4.6 

65–74 years ........................ 4,789 1,065 3.3 0.7 58.5 13.0 70.1 7.5 

75 years and over ..................... 2,630 467 1.8 0.3 42.8 7.6 61.5 8.1 

Race 

White .............................. 120,074 7,096 82.9 1.8 52.5 3.1 89.2 1.2 

Black/African American ................... 17,502 2,450 12.1 1.5 49.5 6.9 93.4 3.2 

Other3 ............................. 7,275 1,575 5.0 1.1 38.7 8.4 93.6 2.1 

Primary expected source of payment 

Private insurance....................... 97,348 6,385 67.2 1.9 48.9 3.2 92.2 1.2 

Medicaid/SCHIP4....................... 17,872 1,809 12.3 1.2 53.8 5.4 94.6 1.7 

Medicare ............................ 14,712 1,657 10.2 1.0 38.3 4.3 73.0 4.1 

Self-pay/charity/no charge ................. 5,834 1,186 4.0 0.8 13.4 2.7 85.6 4.3 

Other5 ............................. 9,085 1,782 6.3 1.2 . . . . . . 86.1 5.3 

. . . Category not applicable. 1Visit rates for age, sex, and race are based on U.S. Census Bureau estimates of the civilian noninstitutional population of the United States as of July 1, 2001. These population estimates reflect 

Census 2000 and are available from the U.S Census Bureau. See ‘‘Technical Notes’’ for more detail. Visit rates by expected source of payment are based on Current Population Survey estimates 

on health insurance coverage (Mills, B. Health Insurance Coverage: 2001 Current Population Reports P60–220 September 2002.) 2Preventive care includes prenatal, general medical, well-baby, and screening or insurance examinations. 3Other race includes visits by Asian, Native Hawaiian or other Pacific Islander, American Indian or Alaska Native, and multiple races. All race categories include visits by persons of Hispanic origin 

and not Hispanic origin. Persons of Hispanic origin may be of any race. Starting with data year 1999, race-specific estimates have been tabulated according to 1997 Standards for Federal Data on 

Race and Ethnicity and are not strictly comparable with estimates for earlier years. However, the percent of visit records with multiple races indicated is small and lower than what is typically found 

for self-reported race. See ‘‘Technical Notes’’ for more details.’’ 4SCHIP is State Children’s Health Insurance Program. 5Other includes Workers’ Compensation, unknown/blank, and payments not classified elsewhere. 
Advance Data No. 346 + August 26, 2004 25 

Table 12. Number and percent distribution of office visits with corresponding standard errors, by physician’s primary diagnosis:

United States, 2002

Number of Standard Standard 

visits in error in Percent error of 

Major disease category and ICD–9–CM code range1 thousands thousands distribution percent 

All visits ............................................... 889,980 28,110 100.0 . . . 

Infectious and parasitic diseases .......................... 001–139 24,431 1,740 2.7 0.2 

Neoplasms........................................ 140–239 25,321 2,477 2.8 0.3 

Endocrine, nutritional, metabolic diseases, immunity disorders ........ 240–279 52,672 5,021 5.9 0.5 

Mental disorders .................................... 290–319 40,016 3,482 4.5 0.4 

Diseases of the nervous system and sense organs............... 320–389 79,417 5,006 8.9 0.5 

Diseases of the circulatory system ......................... 390–459 80,092 5,593 9.0 0.5 

Diseases of the respiratory system ......................... 460–519 112,107 7,239 12.6 0.7 

Diseases of the digestive system .......................... 520–579 30,132 2,287 3.4 0.2 

Diseases of the genitourinary system ....................... 580–629 42,706 2,524 4.8 0.3 

Diseases of the skin and subcutaneous tissue .................. 680–709 42,743 2,910 4.8 0.3 

Diseases of the musculoskeletal and connective tissue ............ 710–739 66,575 5,370 7.5 0.5 

Symptoms, signs, and ill-defined conditions ................... 780–799 55,674 2,862 6.3 0.2 

Injury and poisoning .................................. 800–999 53,143 3,650 6.0 0.4 

Supplementary classification ............................. V01-V82 146,162 7,272 16.4 0.7 

All other diagnoses2 ........................................ 15,787 1,235 1.8 0.1 

Unknown3 .............................................. 23,002 4,256 2.6 0.5 

. . . Category not applicable. 1Based on the International Classification of Diseases, 9th Revision, Clinical Modification (ICD–9–CM) (7). 2Includes diseases of the blood and blood-forming organs (280–289); complications of pregnancy, childbirth, and the puerperium (630–677); congenital anomalies (740–759); certain conditions 

originating in the perinatal period (760–779). 3Includes blank diagnoses, uncodable diagnoses, and illegible diagnoses. 

NOTE: Numbers may not add to totals because of rounding. 
ution of office visits with corresponding standard errors, by selected primary diagnosis groups, according to patient’s sex: United States,

26

Patient’s sex 

Female2 Male3 

Number of Standard Standard Standard Standard 

visits in error in Percent error of Percent error of Percent error of 

and ICD–9–CM codes1 thousands thousands distribution percent distribution percent distribution percent 

.......................... 889,980 28,110 100.0 . . . 100.0 . . . 100.0 . . . 

........................ 401 48,180 4,658 5.4 0.5 5.4 0.5 5.4 0.6 

....................... V20.2 35,935 3,015 4.0 0.3 3.2 0.3 5.2 0.5 

pharyngitis ........ 460–461,463–466 30,141 2,240 3.4 0.2 3.1 0.3 3.7 0.3 

........................ 250 24,877 2,670 2.8 0.3 2.3 0.2 3.5 0.4 

..................... 710–719 23,725 2,205 2.7 0.2 2.8 0.3 2.4 0.2 

........................ V70 22,362 3,226 2.5 0.3 2.5 0.4 2.6 0.5 

..................... 720–724 20,444 2,717 2.3 0.3 2.3 0.3 2.3 0.3 

..................... 725–729 17,766 1,792 2.0 0.2 1.9 0.2 2.1 0.3 

........................ V22 17,585 2,354 2.0 0.3 3.3 0.4 * . . . 

..................... 381–382 16,702 1,509 1.9 0.2 1.6 0.2 2.2 0.2 

............... 140–208,230–234 15,651 2,158 1.8 0.2 1.5 0.3 2.1 0.2 

........................ 473 14,197 1,170 1.6 0.1 1.6 0.2 1.6 0.2 

........................ 477 14,101 3,673 1.6 0.4 1.7 0.4 1.4 0.4 

........................ 493 12,692 1,906 1.4 0.2 1.5 0.3 1.3 0.2 

....................... V72.3 11,883 1,507 1.3 0.2 2.2 0.3 * . . . 

........................ 272 11,767 1,436 1.3 0.2 1.1 0.2 1.6 0.3 

–392.0,393–398,402,404,415–416,420–429 11,670 1,135 1.3 0.1 1.2 0.1 1.5 0.2 

.................... 410–414.9 10,970 1,275 1.2 0.1 0.8 0.1 1.9 0.2 

........................ 462 10,090 1,066 1.1 0.1 1.1 0.1 1.2 0.2 

........................ V67 9,995 1,421 1.1 0.2 1.0 0.2 1.2 0.2 

.......................... 509,248 17,582 57.2 0.9 57.7 0.9 56.5 1.0 

sion.

s, 9th Revision, Clinical Modification (ICD–9–CM) (7). However, certain codes have been combined in this table to form larger categories that better describe the utilization of ambulatory care services.

unding. 

Advance Data No. 346+ August 26, 2004
Advance Data No. 346 + August 26, 2004 27 

Table 14. Number, percent distribution, and annual rate of injury-related office visits with corresponding standard errors, by patient’s

age, sex, and race: United States, 2002

Number of 

Number of Standard Standard visits per Standard 

visits in error in Percent error of 100 persons error of 

Patient’s age, sex, and race thousands thousands distribution percent per year1 rate 

All injury-related visits ......................... 104,028 5,656 100.0 . . . 36.7 2.0 

Age 

Under 15 years ............................. 17,021 1,187 16.4 1.1 28.1 2.0 

15–24................................... 11,327 1,203 10.9 0.9 28.7 3.0 

25–44................................... 27,111 2,068 26.1 1.1 32.7 2.5 

45–64................................... 29,304 2,063 28.2 1.2 44.3 3.1 

65–74................................... 9,186 865 8.8 0.7 50.9 4.8 

75 years and over ........................... 10,080 1,009 9.7 0.9 63.3 6.3 

Sex and age 

Female .................................. 52,036 2,941 50.0 1.1 35.9 2.0 

Under 15 years ........................... 7,306 640 7.0 0.6 24.7 2.2 

15–24 ................................. 5,154 622 5.0 0.5 26.3 3.2 

25–44 ................................. 13,408 1,159 12.9 0.9 31.9 2.8 

45–64 ................................. 14,898 1,244 14.3 0.8 43.7 3.6 

65–74 ................................. 5,073 605 4.9 0.5 51.6 6.1 

75 years and over .......................... 6,196 711 6.0 0.6 63.3 7.3 

Male ................................... 51,992 3,169 50.0 1.1 37.7 2.3 

Under 15 years ........................... 9,714 798 9.3 0.7 31.3 2.6 

15–24 ................................. 6,173 783 5.9 0.6 31.1 3.9 

25–44 ................................. 13,703 1,364 13.2 0.9 33.6 3.3 

45–64 ................................. 14,406 1,189 13.8 0.9 44.9 3.7 

65–74 ................................. 4,112 524 4.0 0.4 50.2 6.4 

75 years and over .......................... 3,884 512 3.7 0.5 63.3 8.3 

Race2 

White ................................... 90,717 5,194 87.2 1.0 39.6 2.3 

Black ................................... 8,870 934 8.5 0.8 25.1 2.6 

Other ................................... 4,441 641 4.3 0.6 23.6 3.4 

. . . Category not applicable. 1Visit rates for age, sex, and race are based on the July 1, 2002, set of estimates of the civilian noninstitutional population of the United States as developed by the Population Division, U.S. 

Census Bureau. These population estimates reflect Census 2000 data and are available from the U.S. Census Bureau. See ‘‘Technical Notes’’ for more details. 2Other race includes visits by Asians, Native Hawaiians or other Pacific Islanders, American Indians or Alaska Natives, and multiple races. All race categories include visits by persons of Hispanic 

and not Hispanic origin. Persons of Hispanic origin may be of any race. Starting with data year 1999, race-specific estimates have been tabulated according to 1997 Standards for Federal Data on 

Race and Ethnicity and are not strictly comparable with estimates for earlier years. However, the percent of visit records with multiple races indicated is small and lower than what is typically found 

for self-reported race. See ‘‘Technical Notes’’ for more details. 

NOTE: Numbers may not add to totals because of rounding. 

Table 15. Number and percent distribution of injury-related office visits with corresponding standard errors, by intent and mechanism of

external cause: United States, 2002

Number of Standard Standard 

visits in error in Percent error of 

Intent and mechanism1 thousands thousands distribution percent 

All injury-related visits ................................ 104,028 5,656 100.0 . . . 

Unintentional injuries ................................ 58,720 4,181 56.4 1.8 

Falls ......................................... 13,319 1,459 12.8 1.1 

Struck against or struck accidentally by objects or persons ....... 8,421 1,119 8.1 0.9 

Overexertion and strenuous movements ................... 7,120 1,016 6.8 0.9 

Motor vehicle traffic ................................ 6,323 948 6.1 0.8 

Natural and environmental factors ....................... 3,317 448 3.2 0.4 

Cutting or piercing instruments or objects .................. 2,050 360 2.0 0.3 

Other and not elsewhere classified2 ...................... 13,207 1,307 12.7 1.1 

Mechanism unspecified ............................. 4,964 735 4.8 0.6 

Intentional injuries3 

.................................. *957 342 *0.9 0.3 

Injuries of undetermined intent .......................... * . . . * . . . 

Adverse effects of medical treatment....................... 4,784 537 4.6 0.5 

Blank cause4 ..................................... 39,512 2,559 38.0 1.8 

. . . Category not applicable. 

* Figure does not meet standard of reliability or precision. 1Based on the International Classification of Diseases, 9th Revision, Clinical Modification (ICD–9–CM), Supplementary Classification of External Causes of Injury and Poisoning (7). A detailed 

description of the ICD–9–CM E-codes used to create the groupings in this table is provided in the ‘‘Technical Notes.’’ 2Includes suffocation, poisoning, other transportation, machinery, firearm, fire and flames, drowning/submersion, nontraffic motor vehicle, and pedal cycle. 3Includes assault, self-inflicted, and other causes of violence. 4Includes illegible entries and blanks. 

NOTE: Numbers may not add to totals because of rounding. 
28 Advance Data No. 346 + August 26, 2004

Table 16. Number and percent of office visits with corresponding standard errors, by diagnostic and screening services ordered or

provided, according to patient’s sex: United States, 2002

Patient’s sex 

Female2 Male3 

Number of Standard Standard Standard Standard 

Diagnostic and screening visits in error in Percent error of Percent error of Percent error of 

services ordered or provided thousands1 thousands of visits percent of visits percent of visits percent 

All visits .............................. 889,980 28,110 . . . . . . . . . . . . . . . . . . 

None ................................ 126,218 8,955 14.2 1.0 13.5 1.0 15.3 1.1 

Examinations 

General medical examination ................. 442,299 20,837 49.7 1.7 48.9 1.8 50.8 1.7 

Other examination ........................ 206,336 13,261 23.2 1.2 25.2 1.2 20.3 1.3 

Diagnostic tests 

Blood pressure .......................... 428,011 21,114 48.1 1.5 51.5 1.7 43.1 1.6 

EKG4 ................................ 31,790 5,694 3.6 0.6 3.5 0.8 3.7 0.5 

Any scope procedure ...................... 18,882 1,978 2.1 0.2 2.1 0.2 2.2 0.3 

Sigmoidoscopy/colonoscopy ................ 9,772 1,527 1.1 0.2 1.0 0.2 1.2 0.2 

Endoscopy ........................... 6,387 791 0.7 0.1 0.8 0.1 0.6 0.1 

Cystoscopy ........................... 1,874 256 0.2 0.0 0.1 0.0 0.3 0.0 

Cardiac stress test ........................ 3,740 662 0.4 0.1 0.3 0.1 0.6 0.1 

Audiometry ............................ 3,706 832 0.4 0.1 0.3 0.1 0.5 0.2 

Tuberculin skin test ....................... 2,839 647 0.3 0.1 0.3 0.1 0.3 0.1 

EEG5 ................................ 825 150 0.1 0.0 0.1 0.0 0.1 0.0 

Fetal monitoring ......................... *1,526 502 *0.2 0.1 *0.3 0.1 . . . . . . 

Laboratory tests 

CBC6 ................................ 78,118 6,319 8.8 0.7 8.8 0.7 8.8 0.7 

Urinalysis ............................. 85,723 7,013 9.6 0.7 11.3 1.0 7.2 0.6 

Cholesterol ............................ 46,260 4,684 5.2 0.5 4.7 0.5 6.0 0.7 

PSA7 ................................ 14,870 1,585 1.7 0.2 . . . . . . 4.1 0.4 

Hematocrit/hemoglobin ..................... 28,321 4,641 3.2 0.5 3.7 0.7 2.4 0.4 

Pap test .............................. 36,341 2,981 4.1 0.3 6.9 0.5 . . . . . . 

Cultures 

Any culture ............................ 31,331 2,601 3.5 0.3 3.7 0.3 3.2 0.3 

Throat/rapid strep test .................... 15,036 1,728 1.7 0.2 1.6 0.2 1.8 0.3 

Urine .............................. 6,066 1,028 0.7 0.1 0.7 0.1 0.6 0.2 

Stool .............................. 1,886 456 0.2 0.1 * . . . * . . . 

Cervical/urethral ........................ 3,933 582 0.4 0.1 0.7 0.1 . . . . . . 

Imaging 

Any imaging ............................ 96,781 5,969 10.9 0.6 12.0 0.7 9.2 0.7 

X ray ............................... 53,458 4,842 6.0 0.5 5.7 0.6 6.4 0.6 

Ultrasound ........................... 8,578 1,047 1.0 0.1 1.2 0.2 0.7 0.1 

Mammography ......................... 17,560 1,916 2.0 0.2 3.3 0.3 . . . . . . 

Other imaging ......................... 32,298 2,062 3.6 0.2 3.9 0.3 3.3 0.3 

Blank ................................ *8,331 3,016 *0.9 0.3 *0.9 0.4 *1.0 0.3 

. . . Category not applicable. 

* Figure does not meet standard of reliability or precision.

0.0 Quantity more than zero, but less than 0.05.

1Total exceeds ‘‘All visits’’ because more than one service may be reported per visit.

2Based on 529,075,000 visits made by females.

3Based on 360,905,000 visits made by males.

4EKG is electrocardiogram.

5EEG is electroencephalogram.

6CBC is complete blood count.

7PSA is prostate-specific antigen.
Advance Data No. 346 + August 26, 2004 29 

Table 17. Number and percent of office visits with corresponding standard errors, by counseling, education, or therapeutic services

ordered or provided, according to patient’s sex: United States, 2002

Patient’s sex 

Female2 Male3 

Number of Standard Standard Standard Standard 

Counseling, education, or therapeutic visits in error in Percent error of Percent error of Percent error of 

services ordered or provided thousands1 thousands of visits percent of visits percent of visits percent 

All visits .............................. 889,980 28,110 . . . . . . . . . . . . . . . . . . 

None ................................ 473,435 17,926 53.2 1.5 52.0 1.6 55.0 1.5 

Counseling/education 

Diet/nutrition ............................ 127,699 7,954 14.3 0.8 15.0 0.9 13.4 0.8 

Exercise .............................. 89,087 7,191 10.0 0.7 10.5 0.8 9.3 0.8 

Mental health/stress management .............. 40,764 4,062 4.6 0.4 4.9 0.5 4.2 0.5 

Weight reduction ......................... 32,050 3,397 3.6 0.4 3.9 0.5 3.1 0.3 

Growth/development....................... 29,100 3,037 3.3 0.3 3.0 0.3 3.6 0.4 

Tobacco use/exposure ..................... 23,674 2,033 2.7 0.2 2.5 0.2 2.9 0.3 

Physiotherapy........................... 22,531 4,710 2.5 0.5 2.4 0.5 2.8 0.5 

Asthma education ........................ 18,339 2,811 2.1 0.3 2.0 0.4 2.1 0.3 

Psychotherapy .......................... 18,231 2,648 2.0 0.3 1.8 0.2 2.3 0.5 

Other ................................ 190,849 13,299 21.4 1.2 22.4 1.3 20.0 1.2 

Blank ................................ 18,498 3,567 2.1 0.4 2.3 0.5 1.8 0.3 

. . . Category not applicable.

1Numbers may not add to totals because more than one type of therapeutic or preventive service may be reported per visit.

2Based on 529,075,000 visits made by females.

3Based on 360,905,000 visits made by males.

Table 18. Number and percent distribution of write-in surgical procedures ordered or performed with corresponding standard errors, by

procedure category: United States, 2002

Number of Standard Standard 

procedures error in Percent error of 

Procedure/operation category1 ICD–9–CM codes in thousands thousands distribution percent 

All write-in surgical procedures ................... 69,796 4,114 100.0 . . . 

Nervous system ............................ 01–05 1,830 385 2.6 0.5 

Eye .................................... 08–16 6,782 1,083 9.7 1.4 

Ear .................................... 18–20 1,458 288 2.1 0.4 

Nose, mouth, and pharynx ...................... 21–29 2,777 459 4.0 0.6 

Cardiovascular system ........................ 35–39 3,393 800 4.9 1.1 

Digestive system ............................ 42–54 5,481 849 7.9 1.2 

Urinary system ............................. 55–59 1,171 216 1.7 0.3 

Male genital organs .......................... 60–64 1,830 324 2.6 0.4 

Female genital organs......................... 65–71 3,927 613 5.6 0.9 

Obstetrical procedures ........................ 72–75 2,032 534 2.9 0.7 

Musculoskeletal system ........................ 76–84 8,820 1,084 12.6 1.6 

Integumentary system ......................... 85–86 29,469 2,705 42.2 2.4 

Other procedures2 ........................... 826 178 1.2 0.3 

. . . Category not applicable. 1Based on the International Classification of Diseases, 9th Revision, Clinical Modification (ICD–9–CM) (7). 2Includes operations on the endocrine system (ICD–9–CM codes 06–07), operations on the respiratory system (ICD–9–CM codes 30–34), operations on the hemic and lymphatic system 

(ICD–9–CM codes 40–41). 

NOTES: Included are responses to the surgery item on the Patient Record form (item 8) (up to two procedures could be reported), and the diagnostic/screening services item (item 6) (up to two 

procedures can be reported in the ‘‘scope procedure-specify’’ and the ‘‘other service-specify’’ categories). Miscellaneous diagnostic and therapeutic procedures (nonsurgical procedures) were not 

included in the total. These procedures, coded to ICD–9–CM volumn 3, range 87–99, represented 113,864,000 procedures. 
30 Advance Data No. 346 + August 26, 2004

Table 19. Number and percent distribution of office visits with corresponding standard errors, by medication therapy and number of

medications provided or prescribed, according to patient’s sex: United States, 2002

Patient’s sex 

Female1 Male2 

Number of Standard Standard Standard Standard 

visits in error in Percent error of Percent error of Percent error of 

Visit characteristic thousands thousands distribution percent distribution percent distribution percent 

Medication therapy3 

All visits .............................. 889,980 28,110 100.0 . . . 100.0 . . . 100.0 . . . 

Drug visits4 ............................ 577,075 20,898 64.8 1.1 65.5 1.2 63.9 1.3 

Visits without mention of medication ............. 312,906 13,755 35.2 1.1 34.5 1.2 36.1 1.3 

Number of medications 

provided or prescribed by a physician 

All visits .............................. 889,980 28,110 100.0 . . . 100.0 . . . 100.0 . . . 

0 ................................... 312,906 13,755 35.2 1.1 34.5 1.2 36.1 1.3 

1 ................................... 239,750 9,396 26.9 0.6 26.9 0.7 27.0 0.7 

2 ................................... 146,236 6,619 16.4 0.5 16.6 0.6 16.2 0.6 

3 ................................... 76,317 4,382 8.6 0.4 8.8 0.5 8.3 0.4 

4 ................................... 39,594 2,699 4.4 0.3 4.4 0.3 4.5 0.3 

5 ................................... 23,309 1,839 2.6 0.2 2.8 0.3 2.3 0.2 

6 ................................... 51,871 4,727 5.8 0.5 6.0 0.5 5.5 0.5 

. . . Category not applicable.

1Based on 529,075,000 visits made by females.

2Based on 360,905,000 visits made by males.

3Includes prescription drugs, over-the-counter preparations, immunizations, and desensitizing agents.

4Visits at which one or more drugs were provided or prescribed by the physician.

NOTE: Numbers may not add to totals because of rounding. 
ution of drug visits, and percent drug visits, drug mentions, and drug mention rates per 100 visits with corresponding standard errors, by

002

Drug visits Drug mentions Percent drug visits Drug mention rates 

Number 

of drug 

Standard Standard Standard Standard Percent Standard mentions Standard 

Number in error in Percent error of Number in error in Percent error of drug error of per 100 error of 

thousands1 thousands distribution percent thousands2 thousands distribution percent visits3 percent visits4 rate 

577,075 20,898 100.0 . . . 1,347,312 58,464 100.0 . . . 64.8 1.1 151.4 4.7 

165,371 10,394 28.7 1.5 402,067 29,010 29.8 1.8 76.8 1.3 186.6 8.1 

115,219 12,442 20.0 1.8 310,006 38,979 23.0 2.3 73.5 3.5 197.8 15.3 

80,814 6,033 14.0 1.0 149,572 12,208 11.1 0.9 67.3 1.5 124.6 4.8 

34,355 4,024 6.0 0.7 57,937 8,608 4.3 0.6 48.9 3.5 82.4 9.1 

25,066 3,227 4.3 0.5 54,150 9,142 4.0 0.7 50.2 3.0 108.4 13.0 21,292 2,581 3.7 0.4 39,180 4,989 2.9 0.4 66.1 2.6 121.6 6.8 17,901 2,759 3.1 0.5 39,735 6,098 2.9 0.5 82.6 2.7 183.5 9.3 

15,889 2,337 2.8 0.4 64,088 10,851 4.8 0.8 76.3 4.8 307.8 30.4 

14,293 2,319 2.5 0.4 23,214 3,901 1.7 0.3 37.6 3.9 61.0 7.7 

8,352 1,078 1.4 0.2 11,760 1,591 0.9 0.1 48.8 3.0 68.6 5.2 

8,033 1,133 1.4 0.2 14,329 2,518 1.1 0.2 47.0 3.3 83.9 10.0 

5,799 587 1.0 0.1 12,368 1,586 0.9 0.1 60.3 3.9 128.5 12.1 

4,773 1,205 0.8 0.2 *10,314 3,313 *0.8 0.2 28.1 4.9 60.7 15.4 

59,919 6,792 10.4 1.1 158,593 19,293 11.8 1.4 57.6 4.5 152.5 15.2 

prescribed by the physician. 

isit). 

ntions (number of drug visits divided by number of office visits multiplied by 100). 

00 visits (number of drug mentions divided by total number of visits multiplied by 100). 

unding. 

Advance Data No. 346+ August 26, 2004 31
32 Advance Data No. 346 + August 26, 2004

Table 21. Number and percent of drug mentions for the 20 most frequently occurring therapeutic classes at office visits with

corresponding standard errors: United States, 2002

Number of Standard Percent Standard 

occurrences error in of drug error 

Therapeutic classfication1 in thousands thousands mentions2 of percent 

NSAIDs3 ........................................ 66,328 4,718 4.9 0.2 

Antidepressants ................................... 60,367 3,714 4.5 0.2 

Antihistamines .................................... 58,060 4,473 4.3 0.3 

Antiasthmatics/bronchodilators .......................... 54,562 5,893 4.0 0.4 

Vaccines/antisera................................... 53,785 4,942 4.0 0.4 

Antihypertensive agents .............................. 49,298 4,364 3.7 0.3 

Hyperlipidemia .................................... 44,065 3,290 3.3 0.2 

Blood glucose regulators .............................. 41,865 4,302 3.1 0.3 

ACE4 inhibitors .................................... 40,927 3,026 3.0 0.2 

Disorders, acid/peptic ................................ 40,812 2,695 3.0 0.1 

Analgesics, non-narcotic .............................. 39,753 3,247 3.0 0.2 

Penicillins ....................................... 38,075 2,540 2.8 0.2 

Diuretics ........................................ 35,942 3,121 2.7 0.2 

Antipyretics ...................................... 34,784 3,047 2.6 0.2 

Analgesics, narcotic ................................. 34,739 2,931 2.6 0.2 

Beta blockers ..................................... 33,090 2,727 2.5 0.2 

Calcium channel blockers ............................. 31,998 2,768 2.4 0.2 

Vitamins/minerals .................................. 30,154 3,297 2.2 0.2 

Antiarthritics ...................................... 28,955 2,408 2.1 0.1 

Estrogens/progestins ................................ 28,359 2,433 2.1 0.2 

1Based on the standard four-digit drug classification used in the National Drug Code (NDC) Directory, 1995 edition (10).

2Based on an estimated 1,347,312,000 drug mentions at office visits in 2002.

3NSAIDs are nonsteroidal anti-inflammatory drugs.

4ACE is angiotensin-converting enzyme.

Table 22. Number and rate of generic substances for the 20 most frequently occurring generic substances in drug mentions at office

visits with corresponding standard errors: United States, 2002

Number of 

generic 

Number of Standard substances Standard 

occurrences error in per 100 error of 

Generic substance in thousands1 thousands drug mentions2 rate 

Acetaminophen ............................. 45,381 3,694 3.4 0.2 

Amoxicillin ................................ 35,791 2,444 2.7 0.2 

Hydrochlorothiazide .......................... 28,406 2,812 2.1 0.2 

Albuterol ................................. 25,174 2,694 1.9 0.2 

Aspirin .................................. 23,409 2,145 1.7 0.1 

Hydrocodone .............................. 21,643 2,206 1.6 0.1 

Fluticasone propionate ........................ 20,626 2,394 1.5 0.2 

Levothyroxine .............................. 19,248 1,992 1.4 0.1 

Atorvastatin calcium .......................... 19,062 1,585 1.4 0.1 

Ibuprofen................................. 17,651 1,397 1.3 0.1 

Lisinopril ................................. 17,320 1,590 1.3 0.1 

Pseudoephedrine............................ 16,770 1,928 1.2 0.1 

Furosemide ............................... 16,507 1,599 1.2 0.1 

Guaifenesin ............................... 15,822 1,793 1.2 0.1 

Metoprolol ................................ 15,767 1,485 1.2 0.1 

Amlodipine................................ 15,643 1,451 1.2 0.1 

Azithromycin .............................. 14,125 1,351 1.0 0.1 

Estrogens ................................ 13,973 1,474 1.0 0.1 

Celecoxib ................................ 13,763 1,641 1.0 0.1 

Triamcinolone .............................. 13,039 1,610 1.0 0.1 

1Frequency of mention combines single-ingredient agents with mentions of the agent as an ingredient in a combination drug. 2Based on an estimated 1,347,312,000 drug mentions at office visits in 2002. 
Advance Data No. 346 + August 26, 2004 33 

Table 23. Number, percent distribution, and therapeutic classification for the 20 drugs most frequently prescribed at office visits with

corresponding standard errors, by entry name of drug: United States, 2002

Number of Standard Standard 

drug mentions error in Percent error of 

Entry name of drug1 in thousands thousands distribution percent Therapeutic classification2 

All drug mentions........... 1,347,312 58,464 100.0 . . . . . . 

Lipitor .................. 18,842 1,577 1.4 0.1 Hyperlipidemia 

Albuterol ................ 15,442 1,860 1.1 0.1 Antiasthmatics/bronchodilators 

Amoxicillin ............... 14,690 1,423 1.1 0.1 Penicillins 

Synthroid................ 14,525 1,708 1.1 0.1 Thyroid/antithyroid 

Lasix .................. 14,004 1,454 1.0 0.1 Diuretics 

Celebrex ................ 13,763 1,641 1.0 0.1 NSAIDs3 

Tylenol ................. 12,919 2,368 1.0 0.2 Nonnarcotic analgesics; antipyretics 

Vioxx .................. 12,650 1,724 0.9 0.1 NSAIDs3 

Augmentin ............... 11,995 1,156 0.9 0.1 Penicillins 

Norvasc ................ 11,853 1,172 0.9 0.1 Calcium channel blockers 

Zyrtec.................. 11,573 1,377 0.9 0.1 Antihistamines 

Zocor .................. 11,429 1,171 0.8 0.1 Hyperlipidemia 

A.S.A.4 ................. 10,670 1,345 0.8 0.1 Nonnarcotic analgesics; antiarthritics; antipyretics 

Prednisone .............. 10,422 1,171 0.8 0.1 Adrenal corticosteroids 

Allegra ................. 10,420 1,315 0.8 0.1 Antihistamines 

Coumadin ............... 10,090 1,273 0.7 0.1 Anticoagulants/thrombolytics 

Atenolol ................ 9,694 1,186 0.7 0.1 Beta blockers 

Claritin ................. 9,208 1,179 0.7 0.1 Antihistamines 

Paxil .................. 9,118 924 0.7 0.1 Antidepressants 

Prevacid ................ 8,981 901 0.7 0.1 Acid/peptic disorders 

All other ................ 1,105,025 46,612 82.0 0.5 . . . 

. . . Category not applicable. 1The entry made by the physician on the prescription or other medical records. This may be a trade name, generic name, or desired therapeutic effect. 

2Therapeutic classification is based on the National Drug Code Directory, 1995 edition (10). In cases where a drug had more than one therapeutic use, it was classified under each therapeutic 

class. 

3NSAIDs are nonsteroidal anti-inflammatory drugs. 

4 A.S.A. is acetylsalicylic acid. 

NOTE: Numbers may not add to totals because of rounding. 

Table 24. Number and percent of office visits with corresponding standard errors, by providers seen: United States, 2002

Number of Standard Standard 

visits in error in Percent error of 

Type of provider thousands1 thousands of visits percent 

All visits ................................. 889,980 28,110 . . . . . . 

Physician................................. 846,167 27,573 95.1 0.6 

Medical/nursing assistant ....................... 243,082 19,551 27.3 1.9 

R.N.2 ................................... 146,513 15,495 16.5 1.6 

L.P.N.3 .................................. 88,902 13,202 10.0 1.4 

Medical technician/technologist ................... 54,983 6,969 6.2 0.7 

Physician assistant........................... 16,264 3,525 1.8 0.4 

Nurse practitioner/midwife ...................... *11,176 3,656 *1.3 0.4 

Other ................................... 31,784 8,038 3.6 0.9 

. . . Category not applicable. 

* Figure does not meet standard of reliability or precision.

1Total exceeds ‘‘All visits’’ because more than one provider may be reported per visit.

2R.N. is registered nurse.

3L.P.N. is licensed practical nurse.
34 Advance Data No. 346 + August 26, 2004

Table 25. Number and percent of office visits with corresponding standard errors, by visit disposition: United States, 2002

Number of Standard Standard 

visits in error in Percent error of 

Disposition thousands1 thousands of visits percent 

All visits ................................... 889,980 28,110 . . . . . . 

Return at specified time.......................... 537,891 20,764 60.4 1.2 

Return if needed, P.R.N2 ......................... 243,944 14,152 27.4 1.1 

No followup planned ............................ 75,206 4,923 8.5 0.5 

Referred to other physician ....................... 65,323 5,689 7.3 0.6 

Telephone followup planned ....................... 24,387 4,711 2.7 0.5 

Admitted to hospital ............................ 4,011 587 0.5 0.1 

Other disposition .............................. 18,454 4,348 2.1 0.5 

Blank ..................................... 20,275 3,629 2.3 0.4 

. . . Category not applicable.

1Total exceeds ‘‘All visits’’ because more than one disposition may be reported per visit.

2 P.R.N. is ‘‘as needed.’’

Table 26. Number and percent distribution of office visits with corresponding standard errors, by time spent with physician:

United States, 2002

Number of Standard Standard 

visits in error in Percent error of 

Time spent with physician thousands thousands distribution percent 

All visits ................................. 889,980 28,110 100.0 . . . 

Visits at which no physician was seen ............... 43,813 5,140 4.9 0.6 

Visits at which a physician was seen................ 846,167 27,573 95.1 0.6 

Total.................................... 846,167 27,573 100.0 . . . 

1–5 minutes ............................. 38,393 5,412 4.5 0.6 

6–10 minutes............................. 181,078 11,403 21.4 1.1 

11–15 minutes ............................ 290,573 12,660 34.3 1.0 

16–30 minutes ............................ 275,653 13,529 32.6 1.3 

31–60 minutes ............................ 57,693 5,996 6.8 0.6 

61 minutes and over ........................ 2,777 637 0.3 0.1 

. . . Category not applicable.

NOTE: Numbers may not add to totals because of rounding.

Table 27. Mean time spent with physician with corresponding standard errors, by physician specialty: United States, 2002

Mean time 

in minutes Standard 

spent with error of 25th 75th 

Physician specialty physician1 mean percentile Median percentile 

All visits ................................. 18.4 0.3 9.9 14.7 19.8 

Psychiatry ................................ 35.2 1.7 19.8 29.6 48.2 

Neurology ................................ 27.9 1.1 14.7 24.1 38.0 

Cardiovascular diseases ....................... 21.4 1.2 13.6 18.0 28.2 

Internal medicine ............................ 20.0 1.2 13.4 17.1 24.2 

General surgery ............................ 19.6 1.0 9.9 14.5 24.4 

Urology .................................. 18.2 0.8 14.1 14.8 19.6 

Obstetrics and gynecology ...................... 18.1 0.9 9.8 14.7 19.8 

Ophthalmology ............................. 17.3 1.1 9.5 14.4 19.6 

Orthopedic surgery........................... 17.1 0.5 13.2 14.3 18.8 

General and family practice ..................... 16.1 0.3 9.8 14.5 19.3 

Pediatrics ................................ 16.1 0.5 9.7 14.5 19.3 

Dermatology............................... 15.2 1.0 9.2 14.1 14.9 

Otolaryngology ............................. 15.1 0.7 9.5 14.3 19.1 

All other specialties .......................... 21.3 1.0 14.1 15.0 25.7 

1Only visits where a physician was seen are included. 
Advance Data No. 346 + August 26, 2004 35 

Table 28. Office-based physician-level estimates with corresponding standard errors, by selected practice characteristics according to

specialty type: United States, 2002

Specialty type Specialty type 

All Primary All Primary 

Practice characteristics specialties care Surgical Medical specialties care Surgical Medical 

Number of physicians Standard error 

All office-based physicians ................... 308,023 154,725 78,430 74,868 8,149 4,674 3,438 3,793 

Percent distribution 

Total sample............................ 100.0 100.0 100.0 100.0 . . . . . . . . . . . . 

Number of in-scope office locations 

One ................................. 86.1 88.1 82.6 85.6 1.3 1.9 2.1 2.4 

More than one .......................... 13.9 11.9 17.4 14.4 1.3 1.9 2.1 2.4 

Number of days practicing 

during random NAMCS week 

0 ................................... 17.7 15.2 19.5 20.9 1.3 1.7 2.0 2.5 

1–2 ................................. 17.7 10.9 27.7 21.4 1.2 1.3 2.2 3.0 

3–4 ................................. 39.0 40.6 38.4 36.1 1.8 2.4 2.5 3.2 

5 or more ............................. 25.7 33.3 14.4 21.7 1.4 2.3 1.8 2.5 

Type of practice 

Solo ................................. 34.3 33.7 32.3 37.8 1.7 2.5 2.8 3.5 

Single-specialty group ...................... 41.0 38.4 47.5 39.7 1.9 2.6 2.9 3.8 

Multispecialty group ....................... 24.7 28.0 20.2 22.5 1.8 2.4 2.6 3.4 

Employment status 

Owner ............................... 72.7 66.6 81.2 76.8 1.8 2.6 2.2 2.8 

Employee ............................. 22.4 28.2 16.2 17.0 1.7 2.5 2.0 2.7 

Contractor ............................. 4.8 5.2 2.7 6.2 0.7 1.1 0.9 1.6 

Percent of physicians1 

Type of consultation2 

Hospital visits ........................... 69.8 70.0 79.5 58.9 1.7 2.5 2.7 3.5 

Telephone consultation ..................... 67.6 73.2 59.0 64.0 1.9 2.5 3.5 3.6 

Home visits ............................ 12.5 19.1 5.6 5.3 1.3 2.4 1.3 1.5 

E-mail/Internet consultation .................. 5.9 6.8 5.0 4.8 1.0 1.5 1.5 1.3 

Mean number in week3 

Office visits ............................ 76.5 92.4 63.5 57.3 1.9 3.2 2.3 3.5 

Telephone consultation ..................... 20.8 26.3 11.5 15.7 1.3 2.1 1.0 2.0 

Hospital visits ........................... 20.5 17.0 17.6 34.1 1.6 2.1 1.5 4.8 

Home visits ............................ 10.1 11.7 2.6 6.0 1.8 2.2 0.7 1.8 

E-mail/Internet consultations .................. 6.0 5.7 7.3 5.2 1.2 1.8 2.4 1.1 

Mean percent 

Percent of revenue 

from selected sources4 

Private insurance......................... 48.3 52.7 43.7 44.1 1.0 1.3 1.4 2.0 

Medicare .............................. 29.8 24.6 28.2 31.8 0.9 1.1 1.3 1.8 

Medicaid .............................. 12.0 14.3 9.9 9.5 0.5 0.8 0.7 1.1 

Other sources........................... 10.3 8.2 9.4 15.9 0.8 0.8 1.2 2.1 

Percent distribution 

Number of managed care contracts 

None ................................ 9.7 6.4 9.2 17.0 1.1 1.5 1.7 2.5 

1–2 ................................. 8.5 7.7 10.3 8.3 0.9 1.3 1.8 1.6 

3–10 ................................ 40.3 43.7 38.7 34.8 2.0 2.8 2.9 3.6 

More than 10 ........................... 35.4 36.5 36.8 31.5 2.0 2.6 2.9 3.7 

Blank ................................ 6.2 5.6 5.1 8.5 1.1 1.3 1.4 2.3 

See footnotes at end of table. 
36 Advance Data No. 346 + August 26, 2004

Table 28. Office-based physician-level estimates with corresponding standard errors, by selected practice characteristics according to

specialty type: United States, 2002—Con.

Specialty type Specialty type 

All Primary All Primary 

Practice characteristics specialties care Surgical Medical specialties care Surgical Medical 

Percent of physicians Standard error 

Percent accepting new 

patients by pay source5 

Any patients ............................ 95.4 94.0 99.0 94.4 0.7 1.1 0.7 1.2 

Self-pay .............................. 90.8 89.4 96.2 87.9 1.1 1.6 1.2 2.1 

Medicare .............................. 80.2 71.8 96.4 80.8 1.2 2.0 1.1 2.3 

Noncapitated private insurance ................ 78.1 80.2 83.1 68.2 1.6 2.2 2.4 3.3 

Medicaid .............................. 70.5 67.4 80.0 66.8 1.7 2.6 2.5 2.9 

Worker’s compensation ..................... 59.2 51.9 77.8 54.7 1.8 2.6 2.6 3.2 

Capitated private insurance .................. 53.4 57.8 49.6 48.1 2.1 2.8 3.4 3.5 

No charge/charity ........................ 53.2 50.5 61.0 50.4 2.0 2.7 3.1 3.5 

Percent of physicians 

Electronic patient records6 

Medical ............................... 17.3 18.0 18.8 14.3 1.1 2.1 2.9 2.7 

Billing ................................ 74.4 77.1 77.5 65.4 1.6 2.3 2.5 3.5 

. . . Category not applicable. 1Percent of physicians reporting any consultations during a typical week of work. Missing values ranged from 12 to 16 percent depending on type of consultation. 2Missing values ranged from 12 to 16 percent depending on type of consulation. 3Mean number of consultations during a typical week of work for physicians with any of that type of consultation. 4Missing values ranged from 10 to 20 percent depending on revenue source. 5Missing values ranged from 3 to 15 percent depending on payment method. The missing value for accepting any new patients is 0.6 percent. 6Missing values are about 1.7 percent for electronic medical records and 5.1 percent for electronic billing records. 

NOTES: Estimates of office-based physicians exclude the specialties of anesthesiology, radiology, and pathology. Numbers may not add to totals because of rounding. 
Advance Data No. 346 + August 26, 2004 37 

Table I. Coefficients appropriate for determining approximate relative standard errors by Technical Notes type of estimate and physician specialty: National Ambulatory Medical Care Survey, 2002

Data collection

The NAMCS data collection is 

authorized under Section 308d of the 

Public Health Service Act (Title 42 

United States Code, Section 306[242k]). 

Participation is voluntary. In 2002, of 

the 1,492 in-scope physicians who 

participated in the NAMCS, 1,233 of 

them completed 28,738 Patient Record 

forms, and 259 physicians reported no 

patients during their sampled week. 

Also, for physicians who completed 

Patient Record forms, 98.5 percent 

(N=1,215) responded fully or 

adequately, and 1.5 percent (N=18) 

responded minimally, for an unweighted 

physician participation rate of 

71.2 percent. 

The U.S. Census Bureau, acting as 

the data collection agent for the survey, 

provided training to field representatives 

(FRs) throughout the Nation. They, in 

turn, oversaw data collection at the 

physician’s office. FRs contacted 

physicians for induction into the survey 

after an advance letter was mailed by 

NCHS notifying the physicians of their 

selection for the survey. In most cases, 

physicians’ and/or their staff completed 

the information requested on the Patient 

Record forms (see figure I). However, in 

30.3 percent of the offices, FRs 

abstracted the data from medical records 

or computer printouts, either alone or 

with the doctor or office staff. No 

personally identifying information such 

as patient name or address is collected. 

Confidentiality of the data collected in 

the survey is protected under the 

Privacy Act, Public Health Service Act, 

Title 42 of the United States Code, 

Section 242m (d), and Title V of the 

E-Government Act of 2002. 

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 does not 

measure any systematic biases in the 

data. 

The standard errors presented in the 

tables and used in tests of significance 

Coefficient for use with 

estimates in thousands 

Lowest reliable 

estimate (in 

Type of estimate and physician specialty A B thousands) 

Visits 

Overall totals ......................... 0.001885 67.975 771 

General and family practice ................ 0.005017 46.488 548 

Internal medicine ...................... 0.012114 117.073 1,504 

Pediatrics ........................... 0.005394 51.389 608 

General surgery ....................... 0.016740 20.945 286 

Obstetrics and gynecology ................ 0.011182 74.840 950 

Orthopedic surgery...................... 0.018688 45.179 634 

Cardiovascular diseases .................. 0.015939 23.877 323 

Dermatology.......................... 0.014560 27.893 370 

Urology ............................. 0.012960 19.354 252 

Psychiatry ........................... 0.016826 36.280 496 

Neurology ........................... 0.009287 8.185 102 

Ophthalmology ........................ 0.012374 71.024 915 

Otolaryngology ........................ 0.015390 13.691 184 

All other specialties ..................... 0.011088 79.546 1,009 

Drug mentions 

Overall totals ......................... 0.003469 132.030 1,526 

General and family practice ................ 0.006536 126.282 1,513 

Internal medicine ....................... 0.018887 330.478 4,647 

Pediatrics ........................... 0.007724 107.747 1,310 

General surgery ....................... 0.042731 52.401 1,109 

Obstetrics and gynecology ................. 0.025114 126.290 1,946 

Orthopedic surgery...................... 0.026888 71.607 1,135 

Cardiovascular diseases .................. 0.031081 79.640 1,352 

Dermatology.......................... 0.014363 63.287 837 

Urology ............................ 0.019728 25.141 358 

Psychiatry ........................... 0.022866 90.933 1,355 

Neurology ........................... 0.015312 21.435 287 

Ophthalmology ........................ 0.027404 124.499 1,989 

Otolaryngology ........................ 0.032009 21.442 370 

All other specialties ..................... 0.016159 271.348 3,675 

NOTE: These coefficients apply to NAMCS data where doctors of osteopathy (D.O.s) have been aggregated with doctors of 

medicine (M.D.s) according to their self-designated practice specialty. For those who wish to conduct a separate analysis on 

visits to doctors of osteopathy, the A and B coefficients for use with visit estimates in thousands are 0.011915 and 29.949, 

respectively. The corresponding coefficients for estimates of drug mentions in thousands are 0.012174 and 99.018. To perform 

analyses of NAMCS data on visits to M.D.’s only, excluding doctors of osteopathy, contact the Ambulatory Care Statistics 

Branch. 

for this report were estimated using 

SUDAAN software. SUDAAN 

computes standard errors by using a 

first-order Taylor series approximation 

of the deviation of estimates from their 

expected values. A description of the 

software and the approach it uses has 

been published (4). 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. 

When it is not feasible to use statistical 

software, such as SUDAAN, for 

analyzing complex survey data, one may 

calculate approximate RSEs for 

aggregate estimates using the following 

general formula, where x is the 

aggregate of interest in thousands, and A

and B are the appropriate coefficients 

from table I. 

RSE(x) = 100 cŒ A + B

x

Similarly, RSEs for an estimate of a 

percent may be calculated using the 

following general formula, where p is 

the percent of interest expressed as a 

proportion, and x is the denominator of 

the percent in thousands, using the 

appropriate coefficients from table I. 
38 Advance Data No. 346 + August 26, 2004

RSE (x) = 100 cŒ B c (1−p) 

p c x

The standard error for a rate may be 

obtained by multiplying the RSE of the 

total estimate by the rate. 

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. 

This 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 

include an asterisk only if the RSE of 

the estimate exceeds 30 percent. 

Estimation

Statistics from the NAMCS are 

derived by a multistage estimation 

procedure that produces essentially 

unbiased national estimates. The 

estimation procedure has four basic 

components: 

+ inflation by reciprocals of the 

sampling selection probabilities 

+ adjustment for nonresponse 

+ a population weighting ratio 

adjustment 

+ weight smoothing 

Estimates from the NAMCS data 

were adjusted to account for sample 

physicians who did not participate in the 

study. This was done in a manner that 

minimized the impact of nonresponse on 

final estimates by imputing to 

nonresponding physicians the practice 

characteristics of similar responding 

physicians. For this purpose, similar 

physicians were judged to be physicians 

having the same specialty designation 

and practicing in the same PSU. In 

2002, the weight from physicians who 

provided a minimal number of Patient 

Record forms was capped. The 

remaining weight for these minimally 

responding doctors was accounted for 

by all in-scope, responding doctors in 

the specialty and PSU. These doctors 

were counted as nonrespondents in the 

response rates presented. 

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 items, 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. 

Coding error rates ranged from 0.1 to 

1.1 for various data items. 

Adjustments for survey

nonresponse—The weighted response 

rate for the 2002 NAMCS was 

71.1 percent. Table II presents weighted 

characteristics of NAMCS respondents 

and nonrespondents, along with 

weighted response rates. Distributions 

were similar, with the exception of 

region, metropolitan status, physician 

specialty where internal medicine 

physicians were less likely to cooperate, 

and practice type. The effect of this 

differential response is minimized in the 

visit estimates in most cases as NAMCS 

uses a nonresponse adjustment factor 

that takes all of these variables into 

account, except practice type. 

Adjustments for item

nonresponse—Item nonresponse rates in 

the NAMCS are generally low 

(5 percent or less). However, levels of 

nonresponse can vary considerably in 

the survey. Most nonresponse occurs 

when the needed information is not 

available in the medical record and/or is 

unknown to the person filling out the 

survey instrument. Nonresponse can also 

result when the information is available, 

but survey procedures are not followed, 

and the item is left blank. In this report, 

the majority of tables include a 

combined entry of ‘‘unknown’’ and/or 

‘‘blank’’ to display missing data. For 

items where combined item nonresponse 

is between 30 and 50 percent, percent 

distributions are not discussed in the 

text. However, the information is shown 

in the tables. These data should be 

interpreted with caution. If nonresponse 

is random, the observed distribution for 

the reported item (i.e., excluding causes 

for which the information is unknown) 

would be close to the true distribution. 

However, if nonresponse is not random, 

the observed distribution could vary 

significantly from the actual distribution. 

Researchers need to decide how best to 

treat items with high levels of missing 

responses. For items with a nonresponse 

greater than 50 percent, data are not 

presented. 

Weighted item nonresponse rates 

(i.e., if the item was left blank or the 

‘‘unknown’’ box was marked) were 

5.0 percent or less for data items with 

the following exceptions: ethnicity 

(21.3 percent), was patient referred for 

this visit (18.4 percent), how many past 

visits in the last 12 months (5.5 percent), 

patient’s PCP (5.6 percent), episode of 

care (9.3 percent), do other physicians 

share patient’s care for this problem or 

diagnosis (13.2 percent), and cause of 

injury (36.8 percent of injury visits). 

For some items, missing values 

were imputed by randomly assigning a 

value from a Patient Record form with 

similar characteristics and were based 

on physician specialty, geographic 

region, and three-digit ICD–9–CM codes 

for primary diagnosis. Imputations were 

performed for the following variables: 

birth year (2.3 percent), sex 

(5.0 percent), race (16.4 percent), and 

time spent with physician (13.1 percent). 

This represents a change from previous 

survey years when imputations were 

also performed for the following 

variables: ethnicity, disposition, and 

providers seen. Beginning in 1997, these 

latter items were no longer imputed. 

Blank or otherwise missing responses 

are noted in the data. 

Tests of significance and rounding

In this report, the determination of 

statistical inference is based on a 

two-tailed t-test. The Bonferroni 
Advance Data No. 346 + August 26, 2004 39 

Table II. Characteristics of the 2002 National Ambulatory Medical Care Survey, physician inequality was used to establish the 

respondents and nonrespondents critical value for statistically significant 

Number of Total sample Responding Nonresponding differences (0.05 level of significance) sampled percent physician physician Weighted 

in-scope distribution3 distribution4 distribution5 response based on the number of possible 

Physician characteristic1 physicians2 (weighted) (weighted) (weighted) rate6 comparisons within a particular variable 

All office-based physicians ....... 2,095 100.0 100.0 100.0 0.711 

Age 

Under 50 years .............. 1,080 54.1 54.9 51.9 0.722 

50 years and over ............ 1,015 45.9 45.1 48.1 0.697 

Sex 

Male .................... 1711 79.6 78.6 82.1 0.702 

Female ................... 384 20.4 21.4 17.9 0.746 

Region7 

Northeast ................. 479 21.3 18.2 29.0 0.607 

Midwest .................. 473 22.6 23.1 21.2 0.729 

South .................... 660 33.3 36.3 25.8 0.776 

West .................... 483 22.8 22.3 24.0 0.695 

Metropolitan status7 

MSA area8 ................. 1,848 87.1 85.5 91.2 0.697 

Non-MSA area8 .............. 247 12.9 14.5 8.8 0.802 

Type of doctor 

Doctor of medicine ............ 1,940 93.8 93.6 94.3 0.709 

Doctor of osteopathy .......... 155 6.2 6.4 5.7 0.734 

Specialty7 

General/family practice ......... 328 18.4 19.7 15.1 0.762 

Internal medicine ............. 156 15.1 12.5 21.6 0.588 

Pediatrics ................. 159 9.7 11.7 4.7 0.860 

General surgery ............. 115 3.8 4.0 3.2 0.755 

Obstetrics and gynecology ....... 120 7.7 8.0 7.1 0.734 

Orthopedic surgery............ 114 4.9 4.4 6.1 0.638 

Cardiovascular diseases ........ 147 4.1 3.5 5.4 0.618 

Dermatology................ 92 2.1 2.3 1.7 0.764 

Urology ................... 115 2.1 2.1 2.2 0.703 

Psychiatry ................. 158 5.5 5.3 6.0 0.683 

Neurology ................. 161 1.9 1.6 2.8 0.584 

Ophthalmology .............. 105 4.4 4.1 5.1 0.663 

Otolaryngology .............. 107 2.0 1.9 2.2 0.679 

All other specialties ........... 218 18.4 19.0 16.9 0.735 

Specialty type9 

Primary care ............... 749 50.0 51.0 47.6 0.725 

Surgical .................. 765 26.1 24.5 30.0 0.668 

Medical ................... 581 23.9 24.5 22.3 0.729 

Practice type7 

Solo ..................... 685 31.6 31.9 31.0 0.717 

Two physicians .............. 167 7.5 6.9 8.9 0.656 

Group/HMO10 ............... 704 33.9 35.0 31.0 0.735 

Medical school/government ...... 31 1.3 1.6 0.5 0.888 

Other .................... 42 1.8 2.2 1.1 0.833 

Unclassified ................ 466 23.9 22.4 27.6 0.666 

1Characteristic information is from the master files of the American Medical Association and the American Osteopathic 

Association. 

2In-scope physicians are those who verified that they were non-Federal and involved in direct patient care in an office-based 

setting, excluding the specialties of radiology, pathology, and anesthesiology. 3Total physicians are those who were selected from the master files of the American Medical Association and the American 

Osteopathic Association. 4Responding physicians are those who were in-scope and agreed to participate in the NAMCS survey. 5Nonresponding physicians are those who were in-scope and refused to participte in the NAMCS survey. 6Numerator is the number of in-scope physicians who participated in the NAMCS or who did not see any patients during their 

sampled reporting week. Denominator is all in-scope sampled physicians. 7Significant difference in response rate p<.05. 8MSA is metropolitan statistical area. 9Specialty type is defined in table IV of the ‘‘Technical Notes.’’ 10HMO is health maintenance organization. 

(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. 

A weighted least-squares regression 

analysis was used to determine the 

significance of trends. For the weighted 

least-squares test, the null hypothesis is 

that the slope, β, of the regression line 

between the two variables of interest 

does not significantly differ from zero, 

and the alternative hypothesis is that it 

does differ from zero (i.e., H0: β=0, and 

HA: β≠0). In this modified least-square 

regression, each estimate is weighted by 

the inverse of the standard error (17). 

In the tables, estimates of office 

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 figures calculated 

from rounded data. 

Race

The instruction for the race item on 

the Patient Record form was changed in 

1999 to be consistent with standards 

issued by the Office of Management and 

Budget to promote comparability of data 

among Federal data sources and so that 

more than one race could be recorded 

per person (18). The new race item 

includes the following groups: white, 

black or African American, Asian, 

Native Hawaiian or other Pacific 

Islander, and American Indian or Alaska 

Native. Respondents could check 

multiple categories for each patient. 

Prior to 1999, only a single race 

category could be checked per person. 

Because of the difference between 

single and multiple race reporting, 

race-specific estimates prior to 1999 are 

not strictly comparable with those from 
40 Advance Data No. 346 + August 26, 2004

1999 and subsequent years. From 1999 

to the present, only a small proportion 

of records had multiple races indicated. 

Where reliable multiple-race estimates 

can be obtained, they are presented in 

one category. Estimates for specific race 

categories reflect visits where only a 

single race was reported. See 

‘‘Population figures and rate 

calculation’’ in the ‘‘Technical Notes’’ 

for more information. 

According to the same standards, 

data on race and Hispanic origin were 

collected separately. Consequently, all 

race categories include visits by persons 

of Hispanic and not Hispanic origin. 

Persons of Hispanic origin may be of 

any race. 

Injury groups

Table 15 presents data on the intent 

and mechanism producing the injuries 

that resulted in visits to physician 

offices. Cause of injury is collected for 

each sampled visit in the NAMCS and 

is coded according to the ICD–9–CM’s 

‘‘Supplementary Classification of 

External Causes of Injury and 

Poisoning.’’ However, for table 15, the 

first-listed cause-of-injury data were 

grouped to highlight the interaction 

between intentionality of the injury and 

the mechanism that produced the injury. 

Table III shows the E-code groupings 

used to produce this table. 

Physician specialty groups

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. 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, unless otherwise noted. 

Table IV shows physician specialty 

groups split into three major categories: 

primary care, surgical specialties, and 

medical specialties based on the AMA 

classification. 

Population figures and rate

calculation

The 2002 visit rates for age, sex, 

race, geographic region, and 

metropolitan status use Census 2000-

based postcensal estimates of the 

civilian noninstitutional population of 

the United States as of July 1, 2002, as 

prepared by the U.S. Census Bureau. 

Between 1992 and 2000, NAMCS and 

NHAMCS visit rates used 1990 

census-based population estimates. The 

change in visit rates due to switching 

from the 1990 census-based population 

estimates to Census 2000-based 

population estimates presented in this 

report for age, sex, and race is minimal. 

To evaluate the effect of the change in 

the base year, the 2000 NAMCS and 

NHAMCS visit rates were calculated 

using both the 1990-based population 

estimates and the 2000-based population 

estimates. In no case were differences in 

the two rates statistically significant. It 

is, therefore, reasonable to conclude that 

the effect of the change in base year has 

little impact on observed trends that 

cross these survey years. For more 

information on rate comparisons, see 

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

ahcd/ahcd1.htm. 

Table III. Reclassification of external cause-of-injury codes for use with National Ambulatory Medical Care Survey data

Intent and mechanism of injury Cause-of-injury code1 

Unintentional injuries ........................... 

Falls .................................... 

Motor vehicle traffic ........................... 

Striking against or struck accidentally by objects or persons . . 

Overexertion and strenuous movements .............. 

Cutting or piercing instruments or objects ............. 

Natural and environmental factors .................. 

Poisoning by drugs, medical substances, biologicals, other 

solid and liquid substances, gases, and vapors ......... 

Fire and flames, hot substance or object, caustic or corrosive 

material, and steam .......................... 

Machinery................................. 

Pedal cycle, nontraffic, and other .................. 

Motor vehicle, nontraffic ........................ 

Other transportation........................... 

Firearm missile.............................. 

Other and not elsewhere classified ................. 

Mechanism unspecified ........................ 

Intentional injuries ............................. 

Assault................................... 

Self-inflicted ............................... 

Other causes of violence ....................... 

Injuries of undetermined intent ..................... 

Adverse effects of medical treatment.................. 

E800–E869, E880–E929 

E880.0–E886.9, E888 

E810–E819 

E916–E917 

E927 

E920 

E900–E909, E928.0–E928.2 

E850–E869

E890–E899, E924

E919

E800–E807(.3), E820–E825(.6), E826.1, E826.9

E820–E825(.0–.5,.7–.9)

E800–807,(.0–.2,.8–.9), E826 (.0,.2–.8), E827–E829, E831, E833–E845

E922

E846–E848, E914–E915, E918, E923, E925–E926, E928.3, E928.8, E929.0–E929.5

E887, E928.9, E929.9

E950–E959, E960–E969, E970–E978, E990–E999 

E960–E969 

E950–E959 

E970–E978, E990–E999 

E980–E989 

E870–E879, E930–E949 

1Based on the ‘‘Supplementary Classification of External Causes of Injury and Poisoning,’’ International Classification of Diseases, 9th Revision, Clinical Modification (ICD–9–CM) (7). 
Advance Data No. 346 + August 26, 2004 41 

Table IV. Reclassification of physician specialty for use with National Ambulatory Medical Care Survey data

Physician specialty group Physician specialty 

Primary care specialties ......Family practice, geriatric medicine (family practice), sports medicine (family practice), general practice, internal medicine/ 

pediatrics, 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, oral and maxillofacial surgery, plastic surgery within 

the head and neck, neurological surgery, pediatric surgery (neurology), pediatric surgery, vascular surgery, plastic surgery, 

surgical oncology, thoracic surgery, and transplant surgery. 

Medical specialties ..........Allergy, addiction medicine, addiction psychiatry, allergy and immunology, allergy and immunology/diagnostic laboratory 

immunology, bronchoesophageal medicine, cardiology, clinical genetics, clinical biochemical genetics, clinical cytogenetics, clinical 

molecular genetics, critical care medicine, dermatology, dermatological immunology/diagnostic laboratory. immunology, diabetes, 

emergency medicine, endocrinology, 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, neurology, nephrology, nutrition, 

occupational medicine, medical oncology, clinical pharmacology, pulmonary critical care medicine, pediatric emergency medicine 

(emergency medicine), psychiatry, 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, undersea medicine. 

Population estimates for race groups 

in the 2002 NAMCS and NHAMCS are 

based on Census 2000 where 

respondents were able to indicate more 

than one race category (as requested by 

the 1997 Standards for Federal Data on 

Race and Ethnicity) (18). The multiple 

race indication was adopted by the 1999 

NAMCS and NHAMCS, but the 

denominators that were available for 

calculating rates in 1999 and 2000 were 

based on estimates from the 1990 

census, which indicated single-response 

race categories. Population estimates for 

2000 were not used as denominators for 

2000 NAMCS and NHAMCS visit rates 

because these estimates were not 

available. In addition, NAMCS and 

NHAMCS had very few records for 

multiple-race persons, so rates for 

single-race groups were calculated by 

dividing estimates by denominators that 

included some unidentifiable multiplerace persons. Starting with 2001, the 

denominators used for calculating 

race-specific visit rates reflect the 

transition to multiple-race reporting. 

Specific race denominators reflect 

persons with a single race identification, 

and a separate denominator is available 

for persons of multiple races. In this 

report, a visit rate for white persons, for 

example, uses a denominator that 

reflects the ‘‘white only’’ population, 

and the numerator is the number of 

visits where white and no other race 

category was reported as the patient’s 

race by the health care provider. 

Data indicate that multiple races are 

recorded less frequently in medical 

records than occur in the general 

population. The 2002 population 

estimates indicate that multiple-race 

persons account for 1.5 percent of the 

total population, and multiple-race 

patients (as indicated by the provider) 

account for 0.3 percent of physician 

office visits. This difference exists 

because physicians are less likely to 

know and record the multiple-race 

preference of the patient and not 

because, after age adjusting, persons 

with multiple races make fewer doctor 

visits. This implies that the race 

population rates calculated in 2002 are 

probably slight overestimates for the 

single-race categories and 

underestimates for the multiple-race 

category. 

The 2002 MSA population estimates 

based on Census 2000 were not 

available from the U.S. Census Bureau. 

They were calculated from data 

provided by the Office of Research 

Methods and Division of Health 

Interview Statistics, NCHS, and are 

based on estimates of the civilian 

noninstitutionalized population of the 

United States as of July 1, 2002, using 

Census 2000 data with adjustments to 

2002 totals. 

Definition of terms

Continuity of care—Continuity of 

care is a goal of health care achieved 

through an interdisciplinary process 

involving patients, families, health care 

professionals, and providers in the 

management of a coordinated plan of 

care. Based on changing needs and 

available resources, the process 

optimizes quality outcomes in the health 

status of clients. It may involve 

professionals from many different 

disciplines within multiple systems. 

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 

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. 

Episode of care—This term 

attempts to measure the nature of the 

care provided at the visit, an initial visit 

versus a followup visit. An episode of 

care begins with the initial visit for care 

for a particular problem and ends when 

the patient is no longer continuing 

treatment. A problem may recur later, 

but that is considered a new episode of 

care. An initial visit may be diagnostic 
42 Advance Data No. 346 + August 26, 2004

in nature, whereas a followup visit may 

be to check progress or continue 

therapy. 

Followup visit—Care was 

previously provided for this problem. 

This is the second or subsequent visit 

for a problem or complaint. 

Illness-related visit—A visit is 

considered illness-related if it was not 

defined as an injury visit as in the 

definition for an injury-related visit. 

Initial visit—This is the first visit 

for care of a particular problem or 

complaint. 

Injury-related visit—A visit is 

injury-related if ‘‘Yes’’ was checked in 

response to item 4a, ‘‘Is this visit related 

to injury, or poisoning, or adverse effect 

of medical treatment?,’’ if a cause of 

injury or a nature of injury diagnosis 

was provided, or if an injury-related 

reason for the visit was reported. 

In-scope physician—An in-scope 

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 the 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. 

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. 

Patient—A patient is an individual 

seeking personal health care services 

who is not currently admitted to any 

health care institution on the premises. 

Primary care physician/provider—A 

primary care physician/provider (PCP) 

plans and provides the comprehensive 

health care of the patient. A visit to the 

patient’s PCP is one in which health 

care is provided by the patient’s PCP or 

by a provider substituting for the 

patient’s PCP. 

Primary care specialist—A primary 

care specialist has designated a primary 

care specialty of general and family 

practice, internal medicine, pediatrics, 

etc. Primary care specialists are grouped 

and presented in table IV of the 

‘‘Technical Notes.’’ The terms ‘‘primary 

care specialties’’ and ‘‘primary care 

specialists’’ are used interchangeably 

throughout this report and refer to the 

self-designated classification by 

physicians in the AMA and AOA 

masterfiles. 

Primary expected source of

payment—The primary expected source 

of payment is the source that to the best 

of the physician or physician’s staff’s 

knowledge describes how charges 

incurred for this visit will be paid: 

+ Self-pay—Charges billed directly to 

the patient that will not be 

reimbursed by a third party. Does not 

include prepaid plans for which 

copayment is charged. 

+ Medicare—Charges paid in part or in 

full by a Medicare plan, including 

payments made directly to the 

hospital as well as payments to the 

patient. 

+ Medicaid/SCHIP—Charges paid in 

part or in full by a Medicaid or State 

Children’s Health Insurance Plan 

(SCHIP), including payments made 

directly to the hospital as well as 

payments to the patient. SCHIP, 

enacted as part of the Balanced 

Budget Act of 1997, gave States the 

opportunity to provide free or 

low-cost insurance coverage to 

low-income children not otherwise 

eligible to be covered by Medicaid. 

States began enrolling children in 

1998 using Medicaid or State-specific 

programs separate from Medicaid, or 

both. By 2000, all States had 

implemented their SCHIP programs. 

+ Private insurance—Charges paid in 

part or in full by a private insurance 

company, health maintenance 

organization (HMO) plan or other 

prepayment plan, including 

independent practice associations 

(IPAs) and preferred provider 

organizations (PPOs). 

+ No charge/charity—Visits for which 

no fee is charged (not including visits 

paid for as part of a total care 

package, e.g., postoperative visits 

included in a surgical fee, pregnancy 

visits for which a flat fee was 

charged, and HMO and prepaid 

systems). 

+ Other sources—All other sources of 

payment not in the preceding 

categories. Charges paid under any 

other local, State, or Federal health 

care program such as workers’ 

compensation programs and 

CHAMPUS. 

+ Unknown—Cases where none of the 

previous sources of payment 

categories was checked. 

Visit—A visit is a direct, personal 

exchange between an ambulatory patient 

seeking care and a physician or a staff 

member working under the physician’s 

supervision for the purpose of rendering 

personal health services. Excluded from 

the NAMCS are encounters where 

medical care was not provided, such as 

phone consultations and e-mail 

consultations, or at visits made to drop 

off specimens, pay bills, or make 

appointments. 
Advance Data No. 346 + August 26, 2004 43 

Figure I. Patient Record form
44 Advance Data No. 346 + August 26, 2004

Trade name disclaimer

The use of trade names is for identification 

only and does not imply endorsement by the 

Centers for Disease Control and Prevention, 

U.S. Department of Health and Human Ser

vices. 

Suggested citation Copyright information National Center for Health Statistics

Woodwell DA, Cherry DK. National Ambulatory All material appearing in this report is in the Director 

Medical Care Survey: 2002 Summary. public domain and may be reproduced or Edward J. Sondik, Ph.D. 

Advance data from vital and health statistics; 

no 346. Hyattsville, Maryland: National Center 

copied without permission; citation as to 

source, however, is appreciated. Deputy Director 

for Health Statistics. 2004. Jack R. Anderson 

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