From Vital and Health Statistics of the National Center for Health Statistics Number 87. March 28, 1983 

. 

Drug Utilization in General and Family Practice 

by Characteristics of Physicians and Office Visits: 

National Ambulatory Medical Care Survey, 1980 

by Beulah K. Cypress, Ph. D., Division of Health Care Statistics 

* 

o 

Introduction 

Women play an increasing role in the provision of 

medical care; young physicians of both sexes enter the 

relatively new specialty of family practice, and physicians who have been in practice for some time tend to 

delay retirement. At the same time, new discoveries in 

medication therapy are announced with great frequency. 

Therefore, it is of interest to know whether a changing 

population of physicians affects the number and kinds of 

drugs prescribed. If differences by sex and age of the 

physician do exist, are they simply the results of the 

structure of the physician’s practice? 

In this report drug utilization statistics are presented 

based on the relationship of the sex of the office-based 

physician and the year of medical school graduation to 

selected visit characteristics: sex and age of the patient, 

status and duration of the visit, major reason for the 

visit, and the type ofphysician’s practice. An examination of these data indicated that the structure of the 

practice was more likely to influence drug utilization 

than was the sex of the physician or the year of medical 

school graduation. 

The data were gathered in 1980 by the National 

Center for Health Statistics by means of the National 

Ambulatory Medical Care Survey (NAMCS), a probability sample survey conducted annually through 1981 

by the Division ofHealth Care Statistics. Brief information about the source of the data, sampling errors, and 

definitions of terms are provided in the technical notes 

at the end of this report. A complete description of the 

survey including limitations and definitions was pub 

lished in Vital and Health Statistics, Series 13, No. 

66.1 The methodology used to collect and process the 

drug information is described in Vital and Health Statistics, Series 2, No. 90.2 

Only physicians engaged in general and family practice were used in this analysis to control for the effect of 

physician specialty on the nature of drug prescription. 

General and family practitioners who have a doctor of 

osteopathy (D. O.) degree were not included because data 

on the age, sex, or year of the physician’s medical school 

graduation were not available. 

The Patient Record form used in the 1980 survey is 

reproduced in figure 1. Up to eight specific drugs, either 

new or continued during the visit may be recorded by 

the physician in item 11, parts a and b. In order to 

present accurately what the physician ordered, prescribed, or provided, drug mentions used in this report 

are based on the physicians’ entries on the Patient Record 

forms. These entries were brand or generic names of 

prescription or nonprescription drugs, though in some 

instances the physician recorded a therapeutic effec~ 

for example, ” allergy relief.” 

Visit characteristics 

Previous reports from NAMCS have demonstrated 

that drug utilization statistics vary widely with physician 

specialty and case-mix. s-s Therefore, when analyzing 

drug utilization patterns by variables such as physician 

sex and year of graduation, it is important to examine 

other factors that may contribute to differences. The 

data presented in tables 1 and 2 are for selected patient 

visit variables that could influence drug prescribing. 

U.S. DEPARTMENT OF HEALTH AND HUMAN SERVICES Public Health Service 
1

2

3

4

5

6

7

8

2 aclmncedata 

ASSURANCE OF CONFIDENTALITV-AII ,“fo,,n,,,. ” wh,. h w..,(! “.r,n,, ,dw!,,l,m,, o” 

01 ,“ cod,vld”.1, , .2(,.,8 ... 0. .“ ,Sabl),hn w”, wtl! be twl(f ,O”f,,l,”,,.1, +wll b, u,ed 0“1, 

b, P,,,.”, ,“y(yd 8“ and for the w, Po,,, 01 ,h, ,“, ”.” ,“’1 w,II “o, 1,, ,+>,cIo,w O, ,, 

1,,,,0 !. ., he, r,.,,.”, 0, used f., ,“” ah,r Pu, c.o,e 

1.	 DATE OF VIS;T 

, 

-

Month 

= 

Men, h 0,, v,,, 

1 � AW,, F’R13BLEM 

2 � CHRONIC PROBLEM, ROUTINE 

3 � CHRONIC PROBLEM, FIARELIP 

4 � F’osTs”riGmwPosT INJURY 

5 � NON.ILLN ESS CARE (ROUTINE 

Owa Ctnw”! .1 H,al Ih, 6duca,, o”, “., { WMI.,<. 

Put) ,, H(.,l, h S,,,,,,. 

O1f,<,.1 Hw,, h R,,e,,,h, S,.,, $,,,,, d,w, 1,<!),,.!<,,,” cNoodgggsZ 

N,, ,0”31 Cent,, 10. Hwlth S,.,,,,,,, 

PATlENT RECORD 

NATIONAL AMBULATORY MEDICAL CARE SURVEY 

4, COLOR OR RACE 5mETHNICITY & PATI ENT’S COMPLAINT(S), SYMPTOM(S), OR OTHER 

1 � WI+ITE 

REASON(S) FOR l+Jl&VISIT [In parienr’s own words] 

2 � BLACK L � HISpANIC a MOST IMPORTANT 

ORIGIN 

3 �A&@y&4&lFlc 2 lJNOT 

HISPANIC b OTHER 

4 � AMERICAN INOIAW 

ALASKAN NATIVE 

&	 DIAGNOSTIC SERVICES THIS VISIT 9. PHYSICIAN’S DIAGNOSES 

\Check all ordered or provided] 

I � NONE 8D EKG a PRINCIPAL OIAGNOSIWPROBLEM ASSOCiate WITH ITEM 63 

2 � LIMITEO HISTORY/EXAM. 9 � VISION TEST. 

3 � GENERAL HISTORY/ExAM. 10 � ENooscoPY 

4 � PAP TEST 11 � MENTAL STATUS 

EXAM b OTHER SIGNIFICANT CURRENT OIAGNOSES 

5 � CL, N,CAL MB7EST 

,, � OTHER (.,,,<.,,,, 

PRENATAL, GENERAL EXAM . 6 � x..,, 

WELL BABY, ETC.) 7 � OLOOO PRESSURE CHECK 

1 I . MEDICATION THERAPY THIS VISIT IJ NONE 

/ Using brand or Keneric names, reco?d all new w?d con n“nued medications ordered, injected, udminisrert’d, or orherwise 

provided at this vist. Include immunizi”~ and desensitizing ugen ts] 

a. FOR PRINCIpAL DIAGNOSES IN lTEM 9a, 

1, 

IF yk. FOR THE


CONDITION IN 2.


ITEM 9.>


3, 

4, 

lzm	 NON-MEDICATION THERAPY 13. v&F..:m# lCheck .1/ services ordered or provided this visit/ 

FOR THIS VISIT 

IDNDNE 6 � DIET COUNSELING 

BY A~HER 

PHYSICIAN? 

2 HpHYsIOTHERAPY 7 �F;:;W&S::;L 

3 � OFFICE SURGERV 

4 � FAMILY pLANNING 

8 HMEDICAL COUNSELING , ‘n ‘fEs 

9 � OTH.5R ,SP..UK, 

5 � psYcHOTI+ERApY/ 

THERAPEuTIC LISTENING ,UNO 

PHS-6105.C (9/79) 

Figure 1. Patient Record 

b. FOR ALL OTHER REASONS 

1. 

2, 

3. 

4, 

� NO FOLLOW.UP PLANNED


� RETuRNATspEcIFIEO TIME


� RETURN IF NEEOEO, P,R, N


lJTELEPI+ONE FOLLOW.UPPLANNEO


� R6FERRE0T00THEf+ pHwi,c,AN


� RETURNEOTO REFERRING PHYSICIAN


� AONIITTO HOSPITAL


� OTHER (SPIk //,}


15, DURATION 

OF THIS 

VISIT 

/ Time ucrzmlly 

speut wirh 

pll,rsician / 

M#n., #,\ 

OMB No. 68-R1498 

They are presented to enhance and clari~ the interpretation of drug utilization presented later. The following 

are noteworthy findings from tables 1 and 2 that maybe . 

factors contributing to drug use differences by sex of the 

physician and year of graduation from medical school. 

�	 Female patients constituted 71 percent of visits to . 

female physicians, compared with 60 percent of 

those to male physicians. 

�	 Patients under 25 years of age accounted for 46 

percent of visits to female physicians but only 29 

percent of those to male physicians. Patients 45 � 

years of age and over constituted 44 percent of visits 

to male physicians, compared with 34 percent of 

those to female physicians. 

Female physicians treated proportionately more 

new patients (27 percent) than males did (11 percent). 

Proportionately more visits involving nonillness care 

(general examinations, gynecolo~cal examinations, 

well-baby, and so forth) took place in female physicians’ offices (25 percent) than in male physicians’ @ 

offices (16 percent). 

Female physicians spent some time in face-to-face 

encounter with virtually all their patients, while 3 per-
aduancedata 3 

Table 1. Percent distribution of office visits to general	 and family practitioners (M. D.) by selected visit characteristics, according to sex of physician and year of 

medical school graduation: United States, 1980 

Sex of physician Year of graduation 

Characteristic Both Before Female Male 1947-50 195 1–60 1961-70 1971-80 sexes 794? 

Total. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 100.0 I 00.0 100.0 100.0 100.0 100.0 100.0 100.0 

Sex of patient 

Female . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 60.1 71.2 59.8 57.1 59:6 59.9 61.4 61.8 

Male . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39.9 28.8 40.2 42.9 40.4 40.1 38.6 38.2 

Age of patient 

Under 15 years . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14.4 26.9 14.1 6.7 12.1 14.0 16.8 22.0 

15–24 years . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15.2 19.1 15.1 9.5 15.1 14.1 16.4 21.1 

25-44 years . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26.7 20.5 26.9 22.9 24.8 26.5 28.1 31.0 

45–64 years . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23.9 18.5 24.1 29.5 27.1 24.9 20.9 16.0 

65 years and over . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19.8 15.0 19.9 31.4 20.9 20.5 17.9 9.9 

Visit status 

New patient . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11.4 27.3 10.9 11.9 8.2 9.3 ‘i0.4 25.9 

Oldpatient, new problem . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34.3 25.4 34.5 26.9 34.2 35.4 37.7 30.0 

Oldpatient, old problem . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 54.4 47.3 54.6 61.2 57.7 55.4 51.9 44.1 

Major reason for visit 

Acute problem . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46.6 40.7 46.8 43.8 43.4 47.1 48.7 49.6 

Chronic problem, routine . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24.6 22.2 24.7 36.6 28.1 23.7 22.9 15.3 

Chronic problem, flareup . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9.1 8.6 9.2 7.3 8.3 9.7 8.8 10.8 

Postsurgery or postinjury . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3.6 3,4 3.6 3.5 3.7 3.8 3.7 2.4 

Nonillness care . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16.0 25.1 15.8 8.8 16.6 75.7 16.0 22.0 

Duration of vis!t 

O minutesl . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.9 3.0 *1.O 2.0 3.9 3.1 2.5 

1-5 minutes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12.3 *3.2 12.5 5.3 13.5 12.1 13.8 13.4 

6-10 mmutes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38.8 29.6 39.0 30.0 38.3 41.8 39.7 34.2 

11-15 minutes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27.4 28.0 27.4 35.1 26.1 26.0 27.4 28.9 

16-30 minutes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16.5 30.5 16.1 23.0 18,5 14.7 14.5 17.7 

31 minutes or more . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.1 8.7 1.9 5.8 1.6 1.5 1.6 3.4 

Type of practice 

solo . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 61.4 32.8 62.2 92.9 85.8 61.7 44.4 21.9 

Other . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38.6 67.2 37.8 7.1 14.2 38.3 55.6 78.1 

1 F@rEsEnt$ VlSltS ,n Wh,ch there was no face-to-face encounter between Patient and physlclan. 

2[”~lude. pa fl”ershlp, group, and other wpes of practice 

Table 2. Average number of office visits per week to general and family cent of visits to male physicians were “O” rninute~ 

practitioner (M. D.) by sex of physician and year of medical school that is, patients were treated by a staff member. 

graduation United States, 1980 Male physicians spent less than 11 minutes in52 

Sex of ph ysician percent of their patient encounters; female physiYear of graduation cians spent that amount of time in 33 percent. About 

Both 

Female Male 39 percent of visits to female physicians lasted 16 sexes minutes or longer, compared with 18 percent of 

visits with the same duration to males. 

Number of visits per 

physician per week � Visits to male physicians were more likely to be to 

Allyears of graduation. . . . . . . . . . . . . . . . . . . . 94 73 96 those in solo practice than in other types of practice, 

BefOre 1941 . . . . . . . . . . . . . . . . . . . . . . . . . . . . 60 43 61 while the reverse was true for females. 

1941–1950 . . . . . . . . . . . . . . . . . . . . . . . . . . . . 90 30 92 

1951–1960 . . . . . . . . . . . . . . . . . . . . . . . . . . . . 

1961 -1970 . . . . . . . . . . . . . . . . . . . . . . . . . . . . 

1971 -1980 . . . . . . . . . . . . . . . . . . . . . . . . . . . 

111 87 111 

102 45 107 

81 54 85 

� In a typical work-week the average female physician 

saw 73 patients in the officq the average male saw 

96. 
4 acklncedata 

�	 Patients under 25 years of age were more likely to 

visit physicians who graduated in recent years than 

those in practice a long time, while the reverse was 

true for patients 45 years of age and older (figure 2). 

�	 Physicians who graduated after 1970 treated proportionately more new patients than physicians who 

graduated in earlier years did. 

�	 Proportions of visits for routine chronic problems 

decreased as the year of graduation became more 

recent. Physicians who graduated in 197 1–80 saw 

proportionately more patients for nonillness care 

than older physicians did. 

�	 There were proportionately more visits lasting 16 

minutes or longer, and fewer that were shorter than 

11 minutes, to physicians who graduated before 

1941 than to those who graduated in later years. 

�	 The more recent the year of graduation, the less 

likely were visits to physicians in solo practice. A 

clear trend toward practice arrangements other than 

solo by more recent medical school graduates is 

indicated in figure 3. 

�	 The most professionally active physicians of both 

sexes were those who graduated in the period 195 l– 

60, but male physicians saw more patients in a 

typical work-week than females did, regardless of 

the year of graduation. 

— 

70 

60 

50 

40 E

al 

P 

30 

20 

10 

0 

Figure 2, 

Age of patient 

= - Under 25 years 

— 45 years snd over 

/0. 

-H -e 

0 

0 

.,0 

I I I I I 

Before 1941-50 1951–60 1961–70 1971-80 

1941 

Year of graduation 

Percent of office visits to general and family practitioners (M.D.}, 

by-sge of pstient and year of medical school graduation: United States, 1980 

100 — 

— solo 

90 - _ Other 

80 

\ / 

/ 

70 \ / 

60 

E 

: 50 z 

n 

40 

30 

20 

10 

o~ 

Before 1941–50 1951-60 1961-70 1971-80 

1941 

Year of graduation 

Figure 3. Percent of office visita to general and family practitioners (M.D.), 

by type of prsctice and year of medical school graduation: United States, 1980 

Drug utilization rates 

Two measures of drug utilization are used in this 

report the percent of drug visits and the drug intensity 

rate. The percent of drug visits refers to the percent of 

visits in which one or more drugs were ordered or provided. The drug intensity rate is the average number of 

drugs ordered during drug visits. It is obtained by dividing the number of drug mentions by the number of drug 

visits. These drug utilization rates by the sex of the physician and the year of medical school graduation (in 10-

year intervals) in terms of the same practice variables 

used to describe the visit estimates shown in table 1 are 

presented in tables 3–5. The percent distribution of drug 

mentions by the precise number of medications is shown 

in table 6. 

Sex of physician 

m 

In general. differences in the utilization rates of 

female&d male physicians were not statistically significant. Differences in rates based on the sex of the patient 

were also not statistically significant. Although female 

2 
� 

� 

dmmedaa5 

Table 3. Percent of drug visits and drug intensity rate, by sex and ege of patient, sex of general and family practitioner (M.D.), and year of medical school graduation: 

Sex and age of patiant 

Sex of patient 

Both sexes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 

Female . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 

Male . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 

Age of patient 

Under 15 years . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 

15-24 years . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 

25-44 years . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 

45-64 years . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 

65 years and over . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 

Sex of patient 

Both sexes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 

Female . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 

Male . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 

Age of patient 

Under 15 years . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 

15-24 years . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 

25-44 years . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 

45-64 years . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 

65 years and over . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 

1A “i~it in which one or more drugswere ordered. 

2Dr”g ~ention~ divided by number Ofdrug visits. 

United States, 1980 

Sex of physician 

Both 

Female Ma!a sexes 

75.7 78.7 75.0 

75.9 76.2 75.9 

74.0 85.0 73.8 

71.5 73.9 71.4 

64.4 67.0 64.3 

72.2 76.9 72.1 

80.1 84.8 80.0 

83.9 97.2 83.6 

1.92 2.01 1.92 

1.97 2.11 1.96 

1.85 1.79 1.85 

1.59 1.85 1.58 

1.58 1.71 1.57 

1.75 1.77 1.75 

2.05 2.21 2.05 

2.36 2.53 2.36 

Year of graduation 

Before 

1947 1941-50 7951-60 1961-70 1971-60 

Percent drug visitsl 

82.8 74.8 78.3 70.6 66.9 

85.1 75.2 79.4 72.0 65.7 

79.7 74.2 76.7 68.5 68.9 

73.5 68.6 77.1 69.8 64.1 

68.6 65.6 66.7 62.6 58.4 

81.8 73.5 74.5 66.6 67.1 

82.9 78.1 83.4 76.4 73.3 

89.6 82.2 85.8 78.3 BO.5 

Rate per drug visit2 

1.91 1.84 2.05 1.87 1.64 

1.97 1.85 2.11 1.94 1.65 

1.81 1.83 1.96 1.75 1.63 

1.84 1.53 1.63 1.60 1.47 

1.55 1.47 1.74 1.47 1.4B 

1.72 1.67 1.90 1.65 1.55 

1.92 1.89 2.22 2.02 1.87 

2.12 2.31 2.46 2.50 2.10 

physicians treated proportionately more female patients 

than male physicians did, they used drugs to treat female patients at about the same rate as their male counterparts. 

Male physicians had a higher proportion of patients 

over 65 years of age than female physicians did. but pr~ 

portionally fewer of those visits resulted in drug therapy 

than those to female physicians (84 percent of visits to 

male physicians, compared with 97 percent to females). 

However, the average number of drugs (drug intensity 

rate) prescribed during those visits was about the same 

for all physicians. Similarly, the drug intensity rates for 

patients under 25 years of age, who were more likely to 

be treated by female physicians than by males, were not 

statistically different by sex of the physician. 

Regardless of the sex of the physician, patients seen 

before were more likely to have drug visits than new 

patients were. However, male physicians ordered more 

drugs during drug visits by returning patients than by 

new patients. The drug intensity rates for new and returningpatients did not differ significantly when the physician was a female. However, when the major reason for 

the patient’s visit was a routine chronic problem, about 

� 91 percent of visits for such care given by female physicians resulted in a drug prescription, compared with 84 

percent of those by male physicians, a statistically significant difference. 

Female physicians also tended to prescribe one or 

more drugs proportionately more often during nonillness 

visits (69 percent] than male physicians did (49 percent). 

The drug intensity rates for the routine care of chronic 

problems and for nonillness care were also higher for 

female physicians than for males. These results may be 

due in part to the relatively larger number of female 

patients seen by female physicians. Also, a higher proportion of female physicians’ visits were for examinations (23 percent) than male physicians were (15 percent). Chronic genitourinary problems treated during 

women’s ofllce visits usually require medication therapy 

while visits for gynecological examinations are likely to 

include contraceptive prescription. Vitamins are commonly used for prenatal care, which is a leading diagnosis in the nonillness category. 

For both female and male physicians the lowest 

drug intensity rate was associated with very short visits 

(less than 6 minutes). Otherwise, the average number of 

drugs prescribed varied only slightly with the longer 

duration of the visit. Female physicians were more 

likely than males were to prescribe at least one drug 

when the visits lasted from 11 to 30 minutes. Because 

female physicians had a higher proportion of visits with 

a duration of 16 minutes or more, it may be that the utilization of drug therapy contributed to the greater visit 

length. 

In comparing drug visits by type of practice for male 

physicians only, it was found that one or more drugs 
6 &llmckw 

Table 4. Percent of drug visits and drug intensity rate, by visit status, major reason for visit, duration of visit, sex of general and family practitioner (M.D.), and year of 

medical school graduation: United Statea, 1980 

Sex of physician Year of graduation @ 

Visit status, major reason for visit, and duration of visit Both Before 

Vkit status 

All patients, . . . . . . . . . . . . . . . . . . . . . 

New patient . . . . . . . . . . . . . . . . . . . . . . . . . 

Oldpatient, new problem, . . . . . . . . . . . 

Oldpatient, old problem . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 

MBjor reason for visit 

Acute problem . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 

Chronic problem, routine. . . . . . . . . . . . 

Chronic. problem. flareup . . . . . . . . . . . . . 

Postsurgery or postinjury . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 

Nonillness care . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 

Duration of visit 

O minutes2 . . . . . . . . . . . . . . . . . . . . . . . ,. 

l-5 minutes . . . . . . . . . . . . . . . . . . . . . . . . . . 

6-10 minutas . . . . . . . . . . . . . . . . . . 

n-15 minutes . . . . . . . . . . . . . . . . . . .


16–30 minutes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .


31minutes OrmOre . . . . . . . . . . . . . . . . .


Visit status 

All patients . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 

New patient . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 

Oldpatient, new problem....,.. . . . . . 

Oldpatient, old problem . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 

Major reason for visit 

Acute problem . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .


Chronic problem, routine . . . . . . . . . . . . . . . .


Chronic problem, flweup . . . . . . . . . . . . . . . . . . . . . . . . . . . .


Postsurgery or postinjury . . . . . . . . . . . . . . . . . . . . . . . . . . . .


Nonillness care . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .


Duration of visit 

O minutes2 . . . . . . . . . . . . . . . . . . . . 

l-5 minutes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 

6-10 minutes . . . . . . . . . . . . . . . . . . . . . . . . . . 

11-15 minutes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 

16-30 minutes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 

31minutes ormOre. , ...,...,.. . . . . . . . . . . . . . . . . . . . . . . 

1A “i~it in which o“e or more drugs were ordered. 

Female Mala sexes 

75.1 78.7 75.0 

67.2 66.9 67.2 

76.0 80.1 75.9 

76.3 84.8 76.1 

80.5 81.3 80.5 

84.0 91.0 83.9 

83.8 “71 .7 84.1 

36.3 *57.2 35.7 

49.7 68.9 48.9 

77.4 77.4 

74.1 *81 .3 74.1 

78.6 79.4 78.6 

74.3 82.2 74.1 

71.0 79.3 70.6 

57.9 “61 .9 57.4 

1.92 2.01 1.92 

1.71 1.99 1.69 

1.80 1.78 1.80 

2.03 2.13 2.03 

1.83 1,85 1.83 

2.17 2.53 2.16 

2.21 “2.00 2,21 

1.51 *1 .56 1.61 

1.49 1.75 1.48 

1,38 1.38 

1,56 “1.14 1.56 

1.91 1.83 1.91 

2.03 1.97 2.03 

2,13 2.32 2.12 

2,02 “2.00 2.02 

1941-50 195 ?-60 7961-70 197 1–80 1947 

Percent drug visitsl 

82.8 74.8 78.3 

71.6 63.7 69.5 

78.6 75.2 80.2 

86.8 76.1 78.6 

86.6 79.6 84.4 

92.0 84.9 83.6 

88.2 86.6 88.0 

*46.9 35.0 33.3 

35.3 48.2 57.1 

*51 .4 92.8 78.9 

88.0 76.5 77.5 

83.4 79.7 81.5 

84.6 73.4 77.4 

84.8 65.3 72.2 

60.5 54.4 69.4 

Rate per drug visi@ 

1 .9t 1.84 2.05 

1.75 ‘1.54 1.88 

1.82 1.81 1.84 

1.97 1.89 2.21 

1.94 1.82 1.94 

1.90 2.01 2.30 

2.12 2.08 2.50 

“1 .61 1.30 1.67 

1.41 1.29 1.62 

*1 .60 1.02 ?.63 

1.25 1.41 1.56 

1.72 1.88 2.04 

2.05 1.98 2.17 

2.08 1.98 2.42 

1.97 1.98 2.14 

70.6 66.9 

59.5 70.2 

71.1 69.1 

72.5 63.5 

76.1 72.5 

80.1 79.2 

75.8 76.0 

38.0 “40.3 

44.8 44.3 

70.6 *69.7 

73.8 65.3 

73.9 70.4 

65.8 70.5 

69.5 67.1 

*53.9 *43.3 

1.87 1.64 

1.83 1.50 

1.77 ? .64 

1.94 1.74 

* 

1.69 1.55 

2.39 1.94 

1.9? 1.81 

1.28 “1.18 

1.21 ‘t.15 

1.18 *1 .02 

1.82 1.44 

1.83 1.62 

1.94 1.74 

2.05 1.69 

“t .87 “2.00 

2RepreSent~ “i~ita in ~hi~h there was no face-to-face encounter between Patient and physician. 

3DruQ ~enrio”~ divided by number of drug visits. 

were mentioned in proportionally more visits to those in 

solo practice (78 percent) than to those in other types of 

practice (70 percent). This difference was not statistically significant for female physicians. However, female 

physicians in multiple practices had a higher proportion 

of c$ug visits than males in multiple practice arrangements did. 

Year of graduation 

It was shown previously that older physicians tended 

to treat older patients, while recent graduates from medical school tended to treat younger patients. An earlier 

reports indicated a high correlation between the age of 

the patient and drug utilization, with rates increasing 

with increasing age. The current study results reflect 

these findings. Physicians who graduated before 1961 

were more likely to include one or more drugs than those 

who graduated in later years were. The most recent 

graduates (197 1–80) prescribed, on the average, fewer 

drugs per drug visit than their older counterparts did. 

They also had the highest proportion of visits with only 

one drug prescribed. However, their drug intensity rates 

for patients 45 years of age and over increased with 

increasing age as did those of other physicians, thus 
akmedaa7 

Table 5. Percent of drug visits and drug intensity rate, by type of physician’s practice, sex of general and family practitioner (M.D.), and year of medical school 

graduatiorx United States, 1980 

e Sex of physician Year of graduation 

Type of practice Both Before Female Male 1941-50 1951-60 1961-70 7971-60 sexes 1941 

Percent of drug visitsl 

Alltypes of practice . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 75.1 78.7 75.0 82.8 74.8 78.3 70.6 66.9 

solo . . . . . . . ... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 78.0 81.6 77.9 82.9 76.2 79.8 74.6 69.7 

Other . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 70.6 77.3 70.3 81.3 66.5 76.0 67.4 66.1 

Rate per drug visit3 

Alltypes of practice . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.92 2.01 1.92 1.91 1.8> 2.05 1.87 1.64 

solo . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.95 2.30 1.94 1.89 1.85 2.08 1.87 1.82 

Other . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.87 1.86 1.87 2.22 1.74 2.01 1.87 1.59 

1A “i~i~ in which one or more drugs were ordered. 

2 ,nclude~ pafl”ership, group. and other twes Of practice. 

3~r”g ~entio”s divided by number of drug visits. 

Table 6. Percent distribution of drug visits to general and family practitioners (M. D.) by number of medications, according to sex of physician and year of medical 

school graduation United States, 1980 

Number of medications 

Sex of physician and year of graduation 4 

Totaf 1 2 3 or 

more 

� Percent distribution

Alldrug visitsl . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 100.0 46.2 30.5 T3.3 9.9 

Sex of physician 

100.0 38.7 38.4 ‘9.0 14.0 

100.0 46.5 30.3 13.4 9.8 

Year of graduation 

100.0 42.3 33.6 16.9 7.2 

100.0 50.3 28.3 13.1 8.3 

100.0 41.6 31.3 14.1 13.0 

100.0 48.7 30.1 12.1 9.1 

100.0 56.5 29.4 9.4 4.7 

1A “Is,t ,n whjch one or more drugs were ordered. 

providing evidence that the rate of drug use depends on proportions of drug visits for nonillness care and postthe age of the patient and not the age of the physician. surgery or postinjury were lowest among all major reaFor all medical school graduates, except the 1971- sons for visit regardless of the physician’s year of grad80 group, proportions of drug visits were higher for old uation. Physicians in practice the longest (graduated 

patients returning to the same physician for care of a before 1941 ) were the least likely to have drug visits for 

continuing probIem than for new patients. On the other noniIlness care (35 percent). This was probably related 

hand, the 197 1–80 graduates were more likely to pre- to the fact that nonillness care given by older physicians 

scribe one or more drugs during initial visits (which was usually for a routine physicaI examination, while 

were likely to be made by young rather than more mature younger physicians provided more pediatric (immunipatients) than during visits by patients returning for zations, and so forth) and prenatal care. 

continuing care. Proportions of drug visits did not vary appreciably 

Physicians who graduated after 1960, and who had with changing duration intervals regardless of the year 

proportionately more patients under 25 years of age of graduation. Only very long visits (31 minutes or 

than other physicians did, had lower proportions of drug longer) had proportionately fewer drug visits than other 

visits for care of acute or chronic problems than physi- durations did. However, the average number of drugs 

cians who graduated before 1961 did. As expected, ordered during drug visits to some groups was related to 

� 
8 admncedata 

the duration of the visit. For physicians who graduated 

before 1961 the drug intensity rate for visits lasting 11 

minutes or more was higher than that for visits lasting 

less than 11 minutes. This difference was not statistically significant for physicians who graduated in later 

years. One possible explanation for this is that both visit 

duration and drug utilization increase with increasing 

patient age group, and physicians who graduated before 

1961 see proportionately more older patients than younger 

physicians do. 

Therapeutic categories 

Sex of physician 

Each drug named by the physician in NAMCS is 

classified according to its desired therapeutic effect 

based on the classification system of the American 

Hospital Formulary Service.G The distribution of drug 

mentions by therapeutic category is shown in table 7. 

The use of certain kinds of drugs tended to follow the 

case-mix pattern of the physician groups. The leading 

category used by physicians of both sexes was central 

nervous system drugs. Serums, toxoids, and vaccines 

(13 percent) was the next largest category prescribed by 

female physicians, and it was significantly greater than 

the 3 percent of the same drugs used by male physicians. 

For male physicians the second ranking therapeutic 

group was anti-infective agents (17 percent), which 

exceeded the use of such drugs by female physicians ( 10 

percent). Other differences between therapeutic categories used by female and male physicians were not 

statistically significant. 

There were some within-category differences depending on the sex of the physician. In the central nervous 

system group, no respiratory and cerebral stimulants * 

were prescribed by females. In the hormones and synthetic substitutes group, males used proportionately 

more adrenals and androgens than females did, while 

females ordered proportionately more contraceptives. 

These results reflect the distribution of patient visits by 

sex of the patients likely to visit female and male physicians. 

Year of graduation 

As might be expected considering the age distributions oftheirpatients, physicians who graduated before 

1941 made greater use of cardiovascular drugs and 

diuretics than their younger counterparts did. Physicians 

who graduated before 1961 were more likely to prescribe 

central nervous system drugs than those who graduated 

later were. The most recent graduates were more likely 

to use antihistamines and skin and mucous membrane 

preparations, reflecting the higher proportions of young 

and female patients who visited them. 

Specific drugs 

The specific drugs most frequently prescribed by 

general and family practitioners (including doctors of 

osteopathy) were listed by age of the patient in Advance Data No. 86.4 A comparison of those data with 

the drug lists generated by the physicians grouped by � 

sex of the physician and year of graduation in the current 

analysis revealed few differences among the groups in 

the drugs named or their relative standing. 

Table 7. Percent distribution of drugs mentioned by general and family practitioners (M. D.) by therapeutic category, according to sex of physician and year of 

medical school graduation: United States, 1980 

Sex of physician Year of graduation 

Therapeutic category7 Both Before 

Female Male 7947-50 1951-60 1961-60 1971–80 sexes 1941 

Percent distribution 

Total . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 100.0 100.0 100.0 100.0 100.0 100.0 100.0 100.0 

Antihistamine drugs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6.7 5.4 6.7 6.3 6.3 5.7 7.5 11.3 

Anti-infective agents . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16.6 9.6 16.8 14.6 14.7 17.2 17.5 18.1 

Autcmomic drugs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4.6 *2.8 4.7 3.4 4.3 4.8 4.5 5.8 

Blood formation and coagulation. . . . . . . . . . . . . . . . . . . . 1.4 ‘2.8 1.4 *1.2 0.9 1.8 1.3 “1.0 

Cardiovascular drugs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10.3 7,8 10.4 14,8 11.7 9.6 9.4 7.7 

Central newoussystem druga . . . . . . . . . . . . . . . . . . . . . . . 18.2 14.5 18,3 17.1 21.4 18.3 16.0 15.8 

Electrolytic, caloric, and water balance . . . 8.6 10.4 8,5 11.1 9.9 8.0 8,2 6.7 

Expectorants and cough preparations . . . . . . . . . . . . . . 3.4 *3,8 3,4 3.7 2.9 3.8 3.0 2.6 

Eye, ear, nose. and throat preparations . . . . . . . . . . . . . . . . . . . . 1.5 ‘1,0 1.6 2.1 “0.7 1.6 1.9 *1.7 

Gastrointestinal drugs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4.8 6.7 4.7 4.6 5.0 4.8 5.1 4.0 

Hormones and synthetic substitutes . . . . . . . . . . . . . . 7.4 7.7 7,4 5.9 6.7 8.2 8.0 6.0 

Serums, toxoida, and vaccines . . . . . . . . . . . . . . . . . . . . . 2.9 13.2 2.6 2.4 3.1 2.8 3.5 2,2 

Skin and mucous membrane preparations . . . . . . . . 5.1 8.4 5,0 4.9 3.9 4.4 6.5 8.6 

Spasmolytic agents . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.8 

Vitamins . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3.8 

Another categoriesz . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.9 

‘0.5 

“3.0 

2.4 

1.9 

3.8 

2.9 

*1.3 

3.1 

3.5 

2.3 

4.0 

2.2 

1,8 

3.8 

3.4 

1.5 

3.5 

2.6 

2.0 

4.4 

2.1 � 1 ~a~ed ~n the ~las~ification system of tha American Hospital Formularv SeWiCe. See reference 13. 

.?.lnc,ude~ ~“tineoPlastic ~ge”t%, diag”~~tic agents, e“ZymeS, gold compounds, heavy metal antagonists, local anesthetics, oxytocics, unclassified therapeutic a9entS, pharmaceutics aids, 

and therapeutic category undetermined. 
&ncedata 9 

@ 

* 

Discussion 

This study was limited because of the small number 

of female physicians in the sample. Females constitute 

approximately 5 percent of the office-based general and 

family practitioners in the NAMCS universe. The female 

general and family practitioners (M. D.’s, doctors of medicine) accounted for 22 percent of all female physicians 

who reported visits in NAMC S: The males accounted 

for21 percent ofthe male physicians in the same specialty. 

However, the relatively large sampling error associated 

with the small size of the female sample made it difficult 

to detect differences. 

Most of the differences in drug utilization between 

female and male physicians can be attributed to the 

differences in the demographic characteristics of their 

patients and the diagnoses commonly associated with 

them. Although the study was restricted to only one 

specialty, it is apparent that in general and family practice, case-mix is influenced by the sex of the physician. 

Similarly, case-mix also depends on the age of the 

physician. A medical practice is built over a period of 

time and it is natural for older patients to continue 

seeking their health care from the same established 

References 

1National Center for Health Statistics, R Gagnon, J. DeLozier, 

and T. McLemore The National Ambulatory Medical Care Survey, 

1979 summary. Vital and Health Statistics. Series 13-No. 66. 

DHHS Pub. No. (PHS) 82-1727. Public Health Service. Washington. U.S. Government Printing Office, Sept. 1982. 

2National Center for Health Statistics, H. Koch The collection and 

processing of drug information, National Ambulatory Medical Care 

‘Survey, United States, 1980. Vital and Health Statistics. Series 2-

No. 90. DHHS Pub. No. (PHS) 82–1 364. Public Health Service. 

Washington. U.S. Government Printing Office, Mar. 1982. 

3National Center for Health Statistics, H. Koch Drug utilization in 

office-based practice by age and sex of thepatient, National Ambulatory Medical Care Survey, United States, 1980. Advance Data 

From Vital andHealth Statistics, No, 81. DHHS Pub. No. (PHS) 

82-1250, Public Health Service. Hyattsville, Md. July 26, 1982. 

physicians. The caseload of the newly graduated physician, on the other hand, typically consists of young 

patients, many of them seeing a physician for the first 

time for preventive care or for self-limiting conditions. 

These differences in visit characteristics were noticeable in the distribution of drugs by therapeutic category. 

As expected, there was a strong correlation between 

case-mix and the categories of drugs most frequently 

used. It is noteworthy, however, that in the choice of 

specific drugs, the age of the physician had no apparent 

effect. Physicians who graduated over 40 years ago 

prescribed the same brand name drugs, many of them 

only recently developed, as those who graduated in 

more recent decades did. Continuing medical education 

courses and seminars, often required for board certification, is one factor in the updating of the physician’s 

medical knowledge. But pharmaceutical discoveries 

proliferate at a rapid pace, and the manufacturers also 

contribute to the modernization of the physician’s treatment arrnarnentarium through their representatives and 

literature. One conclusion that might be drawn from the 

results of this study suggests that the motivation to 

acquire new drug information is common to all age 

physicians. 

4National Center for Health Statistics, B. K. Cypress: Drug utilization in ofFicevisits to primary care physicians, National Ambulatory 

Medical Care Survey, 1980. AdvanceDataFrom VifalandHealfh 

Statistics, No. 86. DHHS Pub. No. (PHHS) 82-1250. Public 

Health Service, Hyattsville, Md. Oct. 8, 1982. 

5Nationa1 Center for Health Statistics, B. K. Cypress Medication 

therapy in office visits for selected diagnoses, National Ambulatory 

Medical Care Survey, 1980. Vital andHealth Stafisfics. Series 13-

No. 71. DHHS Pub. No. (PHS) 82–1 732. Public Health Service. 

Washington. U.S. Government Printing Office, Jan. 1983. 

6American Society of Hospital Pharmacists, Inc.: The A men-can 

Hospifal Formulary Service. Washington. Jan. 1980. 
10 adwncedata 

Technical notes 

Source of data and sample 

design 

The information presented in this report is based on 

data collected by the National Center for Health Statistics (NCHS) through its National Ambulatory Medical 

Care Survey (NAMCS) during 1980. The target universe of NAMCS includes.office visits made within the 

coterminous United States by ambulatory patients to 

nonfederally employed physicians who are principally 

engaged in ofilce practice, but not in the specialties of 

anesthesiology, pathology, or radiology. Telephone contacts and nonofllce visits are excluded. 

NAMCS utilizes a multistage probability sample 

design that involves samples of primary sampling units 

(PSU’S), physicians’ practices within PSU’S, and patient 

visits within physician practices. For 1980 a sample of 

2,959 non-Federal, office-based physicians was selected 

from master files maintained by the American Medical 

Association and the American Osteopathic Association. The physician response rate for 1980 was 77.2 

percent. Sampled physicians were asked to complete 

Patient Records (figure 1) for a systematic random 

sample of ofllce visits taking place during a randomly 

assigned weekly reporting period. During 1980, responding physicians completed 46,081 Patient Records, on 

which they recorded 51,372 drug mentions. Charac-. 

teristics of the physician’s practice, such as primary 

specialty and type of practice, were obtained during an 

induction interview. The National Opinion Research 

Center, under contract to NCHS, was responsible for 

the survey’s field operations. 

For a more detailed discussion of the limitations, 

qualifications, and definitions of the data collected in 

the NAMCS, see Vital and Health Statistics, Series 

13. No. 66.1 

Estimates presented in this report differ from the estimates reported in the National Medical Care Utilization 

and Expenditure Survey (NMCUES), another program of NCHS. The variation in estimates is due to 

differences in survey populations, data collection methodology, and definitions. The NMCUES, cosponsored 

by NCHS and the Health Care Financing Administration 

(HCFA), is a national panel survey of households in 

which information on visits to physicians’ ofilces and 

hospital outpatient departments was collected. Preliminary survey data as well as a discussion of the survey 

methodology are forthcoming from NCHS and HCFA. 

Sampling errors and rounding 

of numbers 

The standard error is primarily a measure of the 

sampling variability that occurs by chance because only 

NOTE: A list of references follows the text, 

9 

a sample, rather than the entire universe, is surveyed. 

The relative standard error of an estimate is obtained by 

dividing the standard error by the estimate itself and is 

expressed as a percent of the estimate. Relative standard 

errors of selected aggregate visit statistics are shown in 

Table I. Standard errors for estimated percents of visits 

are shown in table II. Similar standard errors for drug 

statistics and percents are shown in tables III and IV. 

Tables I and II should be used to obtain the standard 

error of a specific drug mention (e.g., Dyazide). Tables 

III and IV should be used to obtainthe standard error of 

a group of drug mentions (e.g., all drugs prescribed for 

hypertension). 

Estimates of office visits have been rounded to the 

nearest thousand. For this reason detailed figures within 

tables do not always add to totals. Rates and percents 

were calculated on the basis of original, unrounded 

figures and will not necessarily agree precisely with 

percents calculated from rounded data. 

Definitions 

An ambulatory patient is an individual presenting 

himself for personal health services who is neither bedridden nor currently admitted to any health care institution on the premises. 

A physician eligible for NAMCS is a duly licensed 

doctor ofmedicine(M.D.) ordoctorofosteopathy (D. O.) 

currently in ofilce-based practice who spends time in 

caring for ambulatory patients. Excluded from NAMCS 

are physicians who are hospital based, physicians who 

specialize in anesthesiology, pathology, or radiology; 

physicians who are federally employe~ physicians who 

treat only institutionalized patients; physicians employed full time by an institution; and physicians who 

spend no time seeing ambulatory patients. 

An office is a place that the physician identifies as a 

Table 1. Approximate relative standard’errors of estimated number of office 

visits baaed on all physician specialties, NAMCS, 1980 

Relative 

Estimated number of office visits standard 

in thousands error in 

percent 

500.. . . .. .. . .. .. . . .. .. . .. .. .. .. .. . . .. .. . .. .. . . .. . 27.3 

1,000. . .. .. . .. .. . . .. .. .. .. .. . .. .. .. .. .. . .. .. .. .. . 19.5 

2,000. . .. .. . .. .. . . .. .. . . .. .. . .. .. .. .. .. . .. .. .. . . . ?4.1 

5,000 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9.4 

10,000 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7.3 

20,000 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5.9 

50,000 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4.9 

100.000 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4.5 

550,000 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4.1 

Example of use of tab/e; An aggregate estimate of 75,000,000 visits has a relative 

standard error of 4.7 percent, or a standard error of 3,525,000 visits (4.7 percent of 

75,000,000). 
achtancedata 11 

Table Il. Approximate standard errors of percents of estimated numbers of office visits based on all physician specialties: NAMCS, 1980 

Estimatesfpercent Base of percent 

{number of office visits in thousands) 7 or 99 5 or 95 10 or90 20 or 80 30 or 70 50 

* 

* 

Standard error in percent 

8.1 10.8 

5.7 7.6 

4.0 5.4 

2.6 3.4 

1.8 2.4 

1.3 1.7 

0.8 1.1 

0.6 0.8 

0.3 0.3 

12.4 13.5 

8.7 9.5 

6.2 6.7 

3.9 4.3 

2.8 3.0 

2.0 2.1 

1.2 1.3 

0.9 1.0 

0.4 0.4 

2.7 5.9 

1.9 4.2 

1.3 2.9 

0.8 

0.6 

0.4 

0.3 

0.2 

0.1 

Example ofuseoftable:An estimate of 30 percent based on an aggregate of 15,000,000visitshas 

percent). 

Table Ill. Approximate relative standard errrors of estimated number of 

drug mentions based on all physician specialties: NAMCS, 1980 

Relative 

Estimated number of drug mentions standard 

in thousands error in 

percent 

1,000 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27.3 

2,000 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19.7 

5,000 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13.2 

10,000 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10.1 

208000 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8.2 

50.000 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6.8 

100,000 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6.2 

300,000 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5.8 

650,000 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5.7 

Example of use of table: An aggregate estimate of 75,000,000 drug mermons has a relatwe standard error of 6.5 percent, ora standard error of 4,875,000 mentions [6.5 percent 

of 75,000,000]. 

Table IV. Approximate standard errors of percents of estimated numbers 

8ase of percent 

(number of drug mentions in thousands] 1 

1.9 

1.3 

0.9 

0.6 

0.4 

0.2 

a standard error of 2.4 percent, ora relative standard error of 8 percent (2.4 percent + 30 

location for his ambulatory practice. Responsibility 

over time for patient care and professional services 

rendered there generally resides with the individual 

physician rather than an institution. 

A visit is a direct personal exchange between an 

ambulatory patient and a physician or a stti member 

working under the physician’s supervision, for the purpose of seeking care and rendering health services. 

A drug mention is the physician’s entry of a pharmaceutical agent ordered or provided—by any route of 

administration-for prevention, diagnosis, or treatment. 

Generic as well as brand-name drugs are included, as 

are nonprescription as well as prescription drugs. Along 

with all new drugs, the physician also records continued 

medications if the patient was specifically instructed 

during the visit to continue the medication. 

of drug mentions based on all physician specialties NAMCS, 1980 

Estimated percent 

or 99 5 or 95 10 or 90 20 or 80 30 or 70 50 

Standard error in percent 

7,000 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.7 5.8 8.0 10.7 12.2 ~3.3 

2,000 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.9 4.1 5.7 7.6 8.7 9.4 

5.000 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.2 2.6 3.6 4.8 5.5 6.0 

20,000 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0.6 1.3 1.8 2.4 2.7 3.0 

100,000 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0.3 0.6 0.8 1.1 1.2 1.3 

600,000 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0.1 0.2 0.3 0.4 0.5 0.5 

Example of use of table: An estimate of 30 percent based on an aggregate of 12,500,000 drug mantions has a standard error of4.1 percent, ora relative standard error of 13.7 percent (4.1 

percent +30 percent), 
12 acklnceckta


Symbols 

.-. Data not available 

. . . Category not applicable 

Quantity zero 

0.0 Quantity more than zero but less than 

0.05 

z	 Quantity more than zero but less than 500 

where numbers are rounded to thousands 

* Figure does not meet standards of 

reliability or precision 

#	 Figure suppressed to comply with 

confidentiality requirements 

Recent Issues of Advance Data From Vital and Health Statistics 

No. 86. Drug Utilization in Oftice Visits to Primary Care Physiciasw National Ambulatory Medical Care Survey, 1980 (Issued 

October 8, 1982) 

No. 85. Summary Data From the National Inventory of Pharmacistsx United States, 1978-79 (Issued October 8, 1982) 

No. 84. Blood Pressure Levels and Hypertension in Persons Ages 

6-74 Years: United States, 1976-80 (Issued October 8, 1982) 

SUGGESTED CITATION 

National Center for Health Statistics,


B, K. Cypress: Drug utilization in general and


family practice by characteristics of physicians


and office visits, National Ambulatory Medical


Care Sum’ey, 1980. Advance Data From Vital


and Health Statistics, No. 87. DHHS Pub. No.


(PHS) 83-1250. Public Health Service,


Hyattsville, Md. March 18, 1983. 

U.S. DEPARTMENT OF HEALTH


AND HUMAN SERVICES


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No. 83. Deliveries in Shoti-Stay Hospitals: United States, 1980 

(Issued October 8, 1982) 

No. 82. Contraceptive Use Patterns, Prior Source, and Pregnancy 

History of Female Planning Patientx United States, 1980 (Issued: 

June 16, 1982) 

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DHHS Publication No. (PHS) 83–1250