IT+ 

d * d -04 d 

From Vital and Health Statistics of the National Canter for Health Statistics 

~ IiiImmmm

Number 81 � July 26, 1982 

Drug UtilizationinOffice PracticebyAge and Sexof the Patient: 

NationalAmbulatory MedicalCareSurvey, 1980 

by Hugo Koch, Division of Health Care Statistics 

The relationship between the age and sex of ambulatory patients and the drugs ordered or provided 

for them by physicians in office-based practice is explored. Data are presented using fiidings from the 

1980 National Ambulatory Medical Care Survey. 

The National Center for Health Statistics uses the 

National Ambulatory Medical Care Survey (NAMCS) 

to collect descriptive data about the medical care provided in doctors’ offices. Each year NAMCS data collectors contact a representative sample of the 

Nation’s doctors of medicine and osteopathy whose 

primary jobs are office-based, patient-care practice. 

The sampled physicians in turn complete records (figure 1) for a systematic random sample of their office 

visits over a weekly reporting period. When the sampled findings were expanded to approximate the entire universe of office-based care, the result was an 

estimated total of 575,745,000 office visits in calendar 1980. 

The year 1980 was the fmt in the 8-year history 

of NAMCS that respondents reported the number and 

names of the specific drugs they used. (See figure 1, 

item 11.) This resulted in an estimated 679,593,000 

mentions of pharmaceutical agents ordered or provided–by any route of administration-for the purpose of prevention, diagnosis, or treatment. Mentions 

included new or continued medications and nonprescription as well as prescription drugs. The methodology used to collect, classify, and process drug information for the 1980 NAMCS is reported elsewhere.1 

lNation~ centerfor He~th 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) 82-1364. Public Health Service. Washington. 

U.S. Government Printing Office. In press. 

Actual findings of drug utilization for the year have 

appeared in two prior publications.zj 3 

Since the estimates presented in this report are 

based on a sample rather than on the entire universe 

of office visits, the data are subject to sampling variability. The technical notes at the end of the report 

provide a brief explanation of sampling errors, and 

guidelines for judging the precision of estimates. 

General patterns of drug utilization 

Drug utilization may be viewed from differing 

perspectives and measured in differing ways, depending on the needs of the data user (table 1). Three 

evaluative terms require clarification at the outset. 

�	 A drug visit is an office visit at which one or more 

drugs are ordered or provided. In 1980 there were 

an estimated 363.5 million drug visits, comprising 

63 percent of the total 575.7 million office visits. 

.	 The drug mention rate is the average number of 

drugs utilized per office visit, obtained by dividing 

the number of office visits into the number of 

drug mentions. For the entire universe of 575.7 

million office visits, the overall drug mention rate 

was 1.18 drugs per average office visit. 

2Nati~n~ center for He~fi Statktics, T. McL,emore and H. Koch: 

1980 Summary, National Ambulatory Medical Care Survey. Advance 

Data From Vital and Health Statistics, No. 77. DHHS Pub. No. (PHS) 

82-1250. Public Health Service. Hyattsville, Md. Feb. 22,1982. 

3Natio~ Center for H~fi Stattiics, H. Koch: Drugs most frequently 

used in office-based practice, National Ambulatory Medical Care Survey, United States, 1980. Advance Data From Vital and Health Statistics, No. 78. DHHS Pub. No. (PHS) 82-1250. Pnblic Health Service. 

Hyattsville, Md. In preparation. 

U.S. DEPARTMENT OF HEALTH AND HUMAN SERVICES, Public Health Service, Offia? of Health Research,Statistics, and Technology 
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ASSURANCE OF CONFIDENTALITV-A!I Inl. vmwon Whwh would mrrmt tdenofwtm Dmww@nt .1 Hcallh, Educmmn. md welfare


.s+m ,ndw,d. nl.o Dcmt!m, ., . . e$wbl,sh,nml wI! be h.ld confndenml, wll b, umd only Publ,c Hmllh SW”,= A No. 001736
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lwwd m OIher persons w US@ for my other pwmm, Nam. al CQnlw for Health Smmtw 

1, DATE OF VISIT PATlENT RECORD * NATIONAL AMBULATORY MEDICAL CARE SURVEY 

2, yJyHoF & SEX & COLOR OR RACE & ETHNICITY & PATIENT’S COMPLAINT(S), SYMPTOM(S), OR OTHER 

1 � wIIITE 

R EA.%)N(S) FOR ~ VISIT [In pattenr’s own words] 

2 � BLACK I � HISPANIC a, MOST IMPORTANT 

ORIGIN 

__l_l._ :;::” ‘clA:p:fJfi’” 2 QNOT 

Month m“ Year HISPANIC b, OTHER 

~ � AMEFIICAN INDIAN 

ALASKAN NATIVE 

SERVICES THIS VISIT 9, PHYSICIAN’S DIAGNOSES 7. ~;T:~:;::eOR THIS & DIAGNOSTIC 

{Check .1/ ordered or provided/ 

, � NONE , � H@ a, PHI NCIPALDIAGNOSIS/PR OBLEMASSOCIATED WITHITEM 6.3. 

I � AcuTE PROBLEM 2~]LlMlTEDH,STORY,EKAM. 90 VISIONTEST 

2 � CHRONIC PROBLEM, R0u71NE 3 � GENERAL HISTCIRY/eXAM, 10 n 5NooscoPY’ 

3 � CHRONIC pRo6LEM. FLAREup 4 � pAp TE57 11 Q M:;:;,, STATUS 

~ � POST5URGEFWPOST INJURY 5 QCLINICAL LAB TEST 

b, OTHER SIG NIFICANT CURRENT DIAGNOSES 

5 � NON.ILLNES$CARG (ROUTINE ~ ~x.RAy 12 D07HER (Spe.yy) 

PRENATAL, GENERAL EXAM,, 

WELL BABY, ETC.) 7 � BLOCID PRESSURE CHECK 

10.;g:~B;& 11.MEDICATION THERAPY THIS VISIT � NONE 

[Using brand or generic names, record all new and continued mealcations ordered, injected, admtrsistered, or otherwizs 

provided at this vist Include immunizing and desensitizing agen tsj 

a. FOR PRINCIPAL DIAGNOSES IN ITEM 90, 

IOYES zDNO 

1, 

+ 

IF YES, FOR THE 

CONDITION IN 2. 

ITEM%? 

3. 

I � YES 2 � NO 

4. 

~ 12.	 NON-MEDICATION THERAPY 

[Check all services orden?d or provided this visit] 

1 � NONE 6 H DIET COUNSELING 

2 � physiotherapy 7 � FAMILY/SOCIAL 

COUNSELING 

3 � OFFIcE suRGERY 

8DMEoICAL COUNSELING 

4DFAMILY PLANNING


5 � PSYCHOTHERAPYI 

9 � OTH ER (Swcjfy)


THERAPEUTIC LISTENING 

P HS.61 OE-A (9/79) 

.b. FOR ALL OTHER REASONS. 

1. 

2, 

3. 

4. 

~4”p;npy:)ry~;y ‘m. ::~y 

VISIT � NO FOLLO,V-UP PLANNEO [Time actuul~y 

� R~uRNATsPEclFIEo TIME spent with 

physician] � RETURN IF NEEOEO, P.R.N. 

� Telephone FOLLOLV.UP PLANNED 

� R EFERREO TO OTHER PHYSICIAN 

� flET”RNEoToREFERRING Physician 

� AohIITTO HospmAL 

Minutes � OTHER (Specify) 

OMB No. 6B-R149f 

FOR THIS VISIT 

BY A~HER 

PHYSICIAN? 

I � YEs 

ZDNO 

Figure 1. Patient Record from the National Ambulatory Medical Care Survey 

�	 The drug intensity rate is the average number of 

drugs utilized per drug visit, obtained by dividing 

the number of drug visits into the number of drug 

mentions. For the entire 363.5 million drug visits, 

the rate was 1.87 drugs per average drug visit. 

If simple volume of utilization is the desired 

criterion, then–depending on the degree of precision 

required–the data user may count the number of 

drug visits or drug mentions. When this simple enumeration is applied to a study of sex differences, it 

becomes readily apparent that drug visits or mentions 

for female patients substantially outnumbered drug 

visits and mentions for males. The ratio of about 6 to 

4 in favor of female patients closely parallels the ratio 

for office visits in general. However, when drug utilization by the sexes is explored from other perspectives, especially those of average usage, a different 

picture emerges. Examine, for example, the respective 

proportions of all office visits represented by the drug 

visits. For female patients it was 63.3 percent, for 

males 62.8 percent. The difference between the two 

proportions is not statistically significant, since it 

could be due to sampling error or variability. In addition, there is no significant difference between the 

average female and male patient in terms of their respective drug mention rates or drug intensity rates. 
dmcecMa3 

Table 1. Number and percent distribution of office visits and drug mentions, number of drug visits and their percent of office visits, drug mention 

rate, and drug intensity rate, by age and sex of the office patient: United States, 1980 

Office visits Drug visits~ Drug mentions 

Drug Dru.o 

Age and sex of patient Number 

in 

Percent 

distribution 

Number Percent of 

in office visits 

Number Percent 

in distribution 

ment& 

rate2 

in tens%y 

rate3 

thousands thousands thousands 

All patients . . . . . . . . . . . . . . . . . . 575,745 100.0 363,489 63.1 679,593 100.0 1.18 1.87 

Sex 

Female . . . . . . . . . . . . . . . . . . . . . 346,106 60.1 219,216 63.3 413,570 60.9 1.19 1.89 

Male . . . . . . . . . . . . . . . . . . . . . . 229,639 39.1 144,274 62.8 266,023 39.1 1.16 1.84 

Age 

Under15years . . . . . . . . . . . . . . . 109,356 19.0 71,763 65.6 115,643 17.0 1.06 1.61 

15-24years . . . . . . . . . . . . . . . . . . 81,561 14.2 46,353 56.8 75,213 11.1 0.92 1.62 

25-44years . . . . . . . . . . . . . . . . . . 154,695 26.9 87,343 56.5 148,126 21.8 0.96 1.70 

45-64years . . . . . . . . . . . . . . . . . . 129,645 22.5 86,327 66.6 175,572 25.8 1.35 2.03 

65yearsandover . . . . . . . . . . . . . . 100,488 17.5 71,704 71.4 165,038 24.3 1.64 2.30 

Sex and age 

Female 

Under15years . . . . . . . . . . . . . 50,503 8.8 33,395 66.1 54,723 8.1 1.08 1.64 

15-24years . . . . . . . . . . . . . . . . 54,879 9.5 31,350 57.1 49;823 7.3 0.91 1.59 

25-44years . . . . . . . . . . . . . . . . 103,562 18.0 58,025 56.0 97,947 14.4 0.95 1.69 

45-64years . . . . . . . . . . . . . . . . 76,385 13.3 52,223 68.4 106,333 15.6 1.39 2.04 

65yearsandover . . . . . . . . . . . . 60,777 10.6 44,222 72.8 104,745 15.4 1.72 2.37 

Male 

Under15years . . . . . . . . . . . . . 58,852 10.2 38,368 65.2 60,920 9.0 1.04 1.59 

15-24years . . . . . . . . . . . . . . . . 26,682 4.6 15,003 56.2 25,391 3.7 0.95 1.69 

25-44years . . . . . . . . . . . . . . . . 51,134 8.9 29,318 57.3 50,179 7.4 0.98 1.71 

45-64years . . . . . . . . . . . . . . . . 53,260 9.3 34,105 64.0 69,239 10.2 1.30 2.03 

65yearsand over . . . . . . . . . . . . 39,712 6.9 27,481 69.2 60,294 8.9 1.52 2.19 

‘An office visit at which one or more drugs were’ordered or provided. 

2Theaverage number of drugs orderod or provided Per Office visit. 

3The average number of drugs ordered or providedperdrugvisit.


The same measurements maybe applied to drug 

utilization by age groups. When the criterion is a 

simple number of drug visits ormentions, the volume 

of utilization is greatest in the middle years, diminishing in the age interval over 64 years. However, applying the drug mention rate produces a different 

pattern, one showing that average utilization steadily 

increases after the 14th year, reaching its highest 

point in the age group 65 years and over (figure 2). 

For the sex-age groups (figure 3) the drug mention 

rates for female and male patients follow the general 

pattern shown in figure 2, pursuing closely parallel 

paths until they diverge for the age group 65 years 

and over where, at a rate of 1.72 drug mentions per 

office visit, drug utilization by female patients significantly exceeds that for males (1.52). 

Drug utilization: therapeutic categories 

Table 2 measures drug utilization from another 

perspective. Here the differences between the sexes 

and the age groups are described in terms of the 

therapeutic effects that the drugs were intended to 

produce. For example, an examination of total usage 

(by all patients) shows the clear preeminence of mention enjoyed by three therapeutic categories: antiinfective agents, cardiovascular drugs, and central 

nervous system drugs. Together they accounted for 

41 percent of the total 679.6 million drug mentions. 

A comparison of the sexes reveals that: 

FemaIe patients exceeded male patients in the 

proportion of their drug mentions represented by 

the following therapeutic categories: 

� Antineoplastic agents. 

�	 Central nervous system drugs (here, the difference between the sexes was very slight). 

�	 Electrolytic, caloric, and water balance substances, e.g., diuretics (again, the sex difference was slight). 

� Hormones and synthetic substances. 

� Vitamins. 

Male patients exceeded female patients in the proportion of their drug mentions represented by the 

following therapeutic categories: 

� Antihistamine drugs. 

� Anti-infective agents. 

� Cardiovascular drugs. 
---

4


— Femala 

1.70	 r 1.80 Male r 

1.60 1.70 

1.60 

1.50 

1.50 

1.40 -~ 

F 

c 1.40 .: 1.30 c 

?4 1.30 

?

1.20 & 

1.20 

1.10 

1.10 

1.00 1.00 

0.90 0.90 

Under 15-24 25-44 45-64 65 and Under 15-24 25-44 45-64 65 and 

15 over 15 over 

Age of patient Age of patient 

1Average““m&r of drugsorderedor provided PerofficeVisit. 1Avera~ number of drugsorderedor provided perofficevisit. 

Figure 2. Drug mention rate by age of patient: United States, 1980 Figure 3. Drug mention rate by sex and age of patient: United States, 

1980 
amcecMa5 

Table 2. Percent distribution of drug mentions by therapeutic category, according to sex and age of the patient: United States, 1980 

Thempeutic categow’ 

All categories . . . . . . . . . . . . . . . . . . . . . . . . . . . . 

Total . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 

Antihistaminedrugs . . . . . . . . . . . . . . . . . . . . . . . . 

Anti-infectiveagents . . . . . . . . . . . . . . . . . . . . . . . 

Antibiotics . . . . . . . . . . . . . . . . . . . . . . . . . . . . 

Antineoplasticagents . . . . . . . . . . . . . . . . . . . . . . . 

Autonomicdrugs . . . . . . . . . . . . . . . . . . . . . . . . . . 

Blood formationandcoagulation . . . . . . . . . . . . . . . 

Cardiovasculardrugs . . . . . . . . . . . . . . . . . . . . . . . 

Cardiacdrugs . . . . . . . . . . . . . . . . . . . . . . . . . . 

Hypotensiveagents . . . . . . . . . . . . . . . . . . . . . . 

Vasodilatingagants . . . . . . . . . . . . . . . . . . . . . . 

Central nervoussystemdrugs. . . . . . . . . . . . . . . . . . 

Analgesicsandantipyretics . . . . . . . . . . . . . . . . . 

Psychotherapeuticagents . . . . . . . . . . . . . . . . . . 

Sedativesand hypnotics . . . . . . . . . . . . . . . . . . . 

Electrolytic,caloric, andwater balance . . . . . . . . . . . 

Diuretics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 

Expectorants andcough preparations . . . . . . . . . . . . 

Eye, ear, nose, andthroat preparations . . . . . . . . . . . 

Gastrointestinal drugs . . . . . . . . . . . . . . . . . . . . . . . 

Hormones and synthetic substances . . . . . . . . . . . . . 

Adrenals . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 

Sarums,toxoids,andvaccines . . . . . . . . . . . . . . . . . 

Skinandmucous membrane preparations . . . . . . . . . . 

Spasmolyticagents . . . . . . . . . . . . . . . . . . . . . . . . 

Vitamins . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 

Othertherapeuticcategories . . . . . . . . . . . . . . . . . . 

Unknown . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 

Drug mentions 

Sex of patient Age of patient 

All 

patients Female Male Under 1524 

15 years years 

25-44 45-64 

years years 

65 years 

and over 

Numbarinthoueands 

679,593 413.,570 266,023 115,643 75,213 148,126 175,572 165.038 

Percent distribution 

100.00 100.00 100,00 100.00 100.00 100.00 100.00 100.00 

6.47 5.64 7.28 14.60 7.75 7.16 3.90 2.29 

15.44 14.36 17.11 28.49 26.10 17.17 8.73 6.30 

13.26 11.99 15.22 27.03 23.68 14.41 7.01 4.46 

0.79 0.99 0.47 “0.07 �0.18 ‘0.45 1.48 1.14 

3.71 3.70 3.73 2.78 3.09 4.91 4.14 3.12 

1.22 1.38 0.97 �0.46 1.42 1.19 1.18 1.75 

9.49 8.55 10.94 +0.34 “0.53 2.90 13.66 21.44 

3.87 3.23 4.87 ‘0.15 �0.36 1.09 5.28 9.08 

3.33 3.42 3.19 �0.1 1 *0.12 1.32 5.46 6.59 

2.16 1.79 2.72 “0.08 *0.05 ‘0.38 2.78 5.52 

16.29 17.06 15.09 5.84 11.55 21.75 20.72 16.16 

8.51 8.35 8.74 4.47 6.42 9.89 10.33 9.10 

2.41 2.62 2.10 �0.29 1.44 3.39 3.58 2.22 

3.68 4.05 3.12 0.70 2.25 4.76 4.98 4.09 

7.65 8.05 7.02 �0.56 1.59 4.62 11.67 13.81 

6.30 6.70 5.69 40.21 ‘0.93 3.85 9.63 11.69 

2.78 2.53 3.17 6.49 3.30 2.69 1.80 1.07 

3.84 3.58 4.24 4.01 3.10 3.46 3.28 4.98 

3.55 3.47 3.67 2.13 2.41 3.42 4.14 4.56 

8.22 9.98 5.48 1.93 9.76 9.37 10.44 8.52 

2.69 2.67 2.74 1.45 2.42 3.03 3.48 2.56 

3.49 2.94 4.34 14.50 2.52 0.81 0.99 1.28 

8.12 7.88 8.53 8.43 15.77 10.75 5.72 4.61 

1.70 1.40 2.15 1.77 ‘0.53 1.03 1.84 2.64 

3.57 4.67 1.86 0.75 6.57 4.87 2.95 3.66 

2.22 2.04 0.97 4.82 2.37 1.82 1.52 1.42 

1.47 1.49 1.45 1.03 1.47 1.64 1.84 1.25 

lBa5ed on the ph~r~~c~logic.therapeutic classification of the Amarican Society of Hospital Ph8rmecists. Selected categories reproduced with the 

Society’s permission. 

. . 
---

.

�

�

�

�

�

�

6


. Serums, toxoids, and vaccines. 

� Spasmolytic agents. 

There was no significant difference between the 

sexes in their respective utilization of drugs in the 

following therapeutic categories: 

. Autonomic drugs. 

. Blood formation and coagulation agents. 

. Expectorants and cough preparations. 

� Eye, ear, nose, and tlmoat preparations. 

� Gastrointestinal drugs. 

. Skin and mucous membrane preparations. 

Table 2 also shows the effect of advancing age on 

the utilization of the therapeutic categories. Figure 4 

graphically pictures this effect by tracing an age curve 

for the three, most mentioned, therapeutic categories. 

All three are age sensitive. The utilization curve for 

the anti-infective agents shows a steady descent with 

advancing years while the curve for cardiovascular 

drugs rises gradually till the 45th year, then steeply to 

a peak in the age group over 64. The utilization curve 

for central nervous system drugs shows its steepest 

ascent at ages 15-44 years, levels off for the rest of 

the middle years, and finally begins a gradual descent 

in the older years of life. 

Drug utilization: specific drugs 

The data user will note that–in its attempt to 

explore differences related to sex and age of the patient–this report has moved progressively in the 

direction of increasing specificity. The exploration 

ends with the descriptive data in table 3, which list in 

rank order the 10 drugs most frequently mentioned 

for each of the sex-age groups. (Inclusion of trade 

names is for identification only and does not imply 

endorsement by the Public Health Service or the 

United States Department of Health and Human 

Services.) 

The drugs are listed by entry name, that is, by the 

trade or generic name that the doctor recorded on the 

— Anti-infective agents 

.-...s Cardiovascular drugs 

\ Central nervous system drugs 

/ 

/

/’

/’ 

/ “ 

* 

“ 

/ .“ 

.“ 0’ :

.*.* 

. *.*”” 

�*,*..** ........... � I I I 

Under 15-24 25-44 45-64 65 years 

15 years years years years and over 

Age of patient 

Figure 4. Utilization of three therapeutic categories of drugs by age of 

patient, based on percent of drug mentions within respective age 

groups: United States, 1980 

NAMCS visit record (figure 1). (Note: NAMCS respondents were instructed to use the same entry 

name on the NAMCS visit record that they used on 

the patient’s medical recor~ and/or on any prescription written.) 

A superscript following a listed drug indicates a 

drug family; a grouping of drugs whose members have 

the same core name and the same or a closely similar 

therapeutic effect. For example, the drug family 

Aristocortf includes the following members: Aristocort, Aristocort A, Aristocort Forte, Aristocort HP, 

Aristocort Intralesional, and Aristocort R. 
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7

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8

9

10

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9

10

adHxeda7 

Table 3. Number of drug mentions and drug mention rate per 1,000 visits for the 10 drugs most frequently ordered or provided to patients in 

selected sex-age groupx United States, 1980 

Number Drug Number Drug 

Rank Entry name and generic 

of drug 

name(s) of 

mentions 

in 

men tion 

rate per Rank 

1,000 

Entry name and generic 

of drug 

name(s) of 

men tions 

in 

mention 

tate per 

1,000 

thousands visits thousands visits 

Female patients under 15 years Male patients under 15 years 

polio vaccine . . . . . . . . . . . . . . . . . . 3,114 61.7 1 Polio vaccine . . . . . . . . . . . . . . . . . . . . . 3,067 52.1 

Diphtheria tetanus toxoid pertussis . . . . 3,028 60.0 2 Diphtheria tetanus toxoid pertussis . . . . 2,835 48.2 

Amoxicillin . . . . . . . . . . . . . . . . . . . . . . 1,906 37.7 3 Allergy relief, unspecified . . . . . . . . . . . . 2,511 42.7 

Tuberculin tine test . . . . . . . . . . . . . . . . 1,752 34.7 4 Amoxicillin . . . . . . . . . . . . . . . . . . . . . . 2,462 41.8 

Ampicillin . . . . . . . . . . . . . . . . . . . . . . . 1,648 32.6 5 Dimetapp (brompheniramine, phenylPeniciliinf . . . . . . . . . . . . . . . . . . . . . . . . 1,646 32.6 eplwine, phenylpropanolamine) . . . . . . 2,21,2 37.6 

Dimetapp (brompheniramine, phenyl- 6 Penicillinf . . . . . . . . . . . . . . . . . . . . . . . . 1,720 29.2 

ephrine, phenylpropanolamine) . . . . . . 1,471 29.1 7 Tuberculin tinetest . . . . . . . . . . . . . . . . 1,696 28.8 

8 Allergy relief, unspecified . . . . . . . . . . . . 1,325 26.2 8 Ampicillin . . . . . . . . . . . . . . . . . . . . . . . 1,635 27.8 

9 Aspirin . . . . . . . . . . . . . . . . . . . . . . . . . . 1,096 21.7 9 Aspirin . . . . . . . . . . . . . . . . . . . . . . . . . . 1,324 22.5 

10 E.E.S . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1,041 20.6 10 Amoxil(amoxicillin) . . . . . . . . . . . . . . . 1,230 20.9 

Female patients 15-24 years Male patients 15-24 years 

1 Tetracyclinef . . . . . . . . . . . . . . . . . . . . . 1,642 29.9 Tetracyclinef . . . . . . . . . . . . . . . . . . . . . 1,394 52.2 

2 Ampicillin . . . . . . . . . . . . . . . . . . . . . . . 1,291 23.5 Penicillinf . . . . . . . . . . . . . . . . . . . . . . . . 828 31.0 

3 Penicillin . . . . . . . . . . . . . . . . . . . . . . . . 1,183 21.6 Allergy relief, unspecified . . . . . . . . . . . . 801 30.0 

4 Ortho-Novum (rrorethindrone, Cieocinf (clindamycin) . . . . . . . . . . . 773 29.0 

mestranol) . . . . . . . . . . . . . . . . . . . . . . 1,000 18.2 Ampicillin . . . . . . . . . . . . . . . . . . . . . . . 664 24.9 

5 Prenatal vitamins . . . . . . . . . . . . . . . . . . 972 17.7 Aspirin . . . . . . . . . . . . . . . . . . . . . . . .. . . 473 17.7 

6 Cleocinf (clindamycin) . . . . . . . . . . . . . . 969 17.7 Minocin (minocyciine) . . . . . . . . . . . . . . *376 *14.1 

7 Lo/Ovral (norgestrel, ethinyl, Tetanustoxoid . . . . . . . . . . . . . . . . . . . . *326 *12.2 

estradiol) . . . . . . . . . . . . . . . . . . . . . . . 796 14.5 Erythromycin . . . . . . . . . . . . . . . . . . . . . ’313 *11.7 

8 Allergy relief, unspecified . . . . . . . . . . . . 725 13.2 Desquam-Xf (benzoyl peroxide, 

9 Materna (multivitamins prenatal) . . . . . . 692 12.6 disodium edetate, etc.) . . . . . . . . . . . . . *299 *11.2 

10 Monistatf (miconazole) . . . . . . . . . . . . . 682 12.4 

Female patients 25-44 years Male patients 2544 years 

Tetracyclinef . . . . . . . . . . . . . . . . . . . . . 1,961 18.9 Allergy relief, unspecified . . . . . . . . . . . . 1,062 20.8 

Allergy relief, unspecified . . . . . . . . . . . . 1,579 15.2 Penicillin . . . . . . . . . . . . . . . . . . . . . . . . 1,022 20.0 

Ampicillin . . . . . . . . . . . . . . . . . . . . . . . 1,565 15.1 Tetracyclinef . . . . . . . . . . . . . . . . . . . . . 987 19.3 

Penicillin . . . . . . . . . . . . . . . . . . . . . . . . 1,370 13.2 Ampicillin . . . . . . . . . . . . . . . . . . . . . . . 971 19.0 

Lasix(furosemide) . . . . . . . . . . . . . . . . . 1,209 11.7 Valium (diazepam) . . . . . . . . . . . . . . 644 12.6 

Prenatal vitamins . . . . . . . . . . . . . . . . . . 1,109 10.7 Aspirin . . . . . . . . . . . . . . . . . . . . . . . . . . 607 11.9 

Vitamin B-12 . . . . . . . . . . . . . . . . . . . . . 1,095 10.6 Erythromycin . . . . . . . . . . . . . . . . . . . . . 585 11.4 

Valium (diazepam) . . . . . . . . . . . . . . . . . 1,091 10.5 Keflex (cephalexin) . . . . . . . . . . . . . . . . 571 11.2 

Monistatf (miconazole) . . . . . . . . . . . . . 1,069 10.3 Actifed (tripolidine, pseudoephedrine) . . 552 10.8 

Chorionic gonadotropin . . . . . . . . . . . . . 1,001 9.7 Darvocet-N (acetaminophen, propoxyphene napsyIate) . . . . . . . . . . . . . 549 10.7 

Female patients 45-64 years Male patients 45-64 years 

Inderal (propranoloi) . . . . . . . . . . . . . . . 1,904 24.9 Inderal (propranolol) . . . . . . . . . . . . . . . 2,295 43.1 

Lasix(furosemide) . . . . . . . . . . . . . . . . . 1,804 23.6 Dyazide (triamterene) . . . . . . . . . . . . . . 1,258 23.6 

Premarin (conjugated estrogens) . . . . . . . 1,704 22.3 Lasix(furosernide) . . . . . . . . . . . . . . . . . 1,157 21.7 

Dyazide (triamterene) . . . . . . . . . . . . . . 1,675 21.9 Valium (diazepam) . . . . . . . . . . . . . . 1,105 20.7 

Motrin (ibuprofen) . . . . . . . . . . . . . . . . . 1,652 21.6 Hydrochlorothiazide . . . . . . . . . . . . . 1,000 18.8 

Valium (diazepam) . . . . . . . . . . . . . . . . . 1,594 20.9 Insulin. . . . . . . . . . . . . . . . . . . . . . . . . . 950 17.B 

Hydrochlorothiazide . . . . . . . . . . . . . . . 1,548 20.3 Lanoxin(digoxin) . . . . . . . . . . . . . . . . . 947 17.8 

Vitamin B-12 . . . . . . . . . . . . . . . . . . . . . 1,348 17.6 Tagamet (cimetidine) . . . . . . . . . . . . . . . 936 17.6 

Aldomet (methyldopa) . . . . . . . . . . . . . . 1,295 17.0 Lopressor (metoprolol) . . . . . . . . . . . . . 877 16.5 

Thyroid . . . . . . . . . . . . . . . . . . . . . . . . . 1,246 16.3 Hydrodiuril (hydrochlorothiazide) . . . . . 871 16.4 

Female patients 65 years and over Male patients 65 years and over 

Lanoxin (digoxin) . . . . . . . . . . . . . . . . . 3,089 50.8 Lasix (furosemide) . . . . . . . . . . . . . . . . . 2,247 56.6 

Lasix(f,~rosemide) . . . . . . . . . . . . . . . . . 2,931 48.2 Lanoxin (digoxin) . . . . . . . . . . . . . . . . . 2,078 52.3 

Dyazide (triamterene) . . . . . . . . . . . . . . 2,613 43.0 Inderal (propranolol) . . . . . . . . . . . . . . . 1,609 40.5 

Irrderal (propranolol) . . . . . . . . . . . . . . . 2,576 42.4 Digoxin . . . . . . . . . . . . . . . . . . . . . . . . . 1,512 38.1 

Aldomet (methyldopa) . . . . . . . . . . . . . . 2,067 34.0 Isordil (isosorbide) . . . . . . . . . . . . . . . . . 1,143 28.8 

Vitamin B-1 2 . . . . . . . . . . . . . . . . . . . . . 1,987 32.7 Dyazide (triamterene) . . . . . . . . . . . . . . 956 24.1 

Digoxin . . . . . . . . . . . . . . . . . . . . . . . . . 1,793 29.5 Aspirin . . . . . . . . . . . . . . . . . . . . . . . . . . 765 19.3 

Motrin (ibuprofen) . . . . . . . . . . . . . . . . . 1,467 24.1 Hydrochlorothiazide . . . . . . . . . . . . . . . 761 19.2 

Insulin . . . . . . . . . . . . . . . . . . . . . . . . . . 1,382 22.7 Hydrodiuril (hydrochlorothiazide) . . . . . 742 IB.7 

Hydrochlorothiazide . . . . . . . . . . . . . . . 1,340 22.0 Prednisone . . . . . . . . . . . . . . . . . . . . . . . 715 18.0 

Superscriptf denotes drug family. 

A , 
Symbols 

. . . Data not available 

. . . Category not applicable 

Quantity zero 

0.0	 Quantity more than zero butless 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 (more than 

30 percent relative standard error) 

# Figure suppressed to comply with 

confidentiality requirements 

I 
Technical notes 

Source of data and sample design 

The estimates presented in this report are based 

on data collected during 1980 by the National Center 

for Health Statistics by means of the National 

Ambulatory Medical Care Survey. The target universe 

of NAMCS comprises office visits made by ambulatory patients to non-Federal physicians who are 

principally engaged in office-based, patient care practice. Visits to physicians practicing in Alaska and 

Hawaii are excluded from the range of NAMCS, as are 

visits to physicians who specialize in anesthesiology, 

pathology, and radiology. 

NAMCS uses a multistage probability sample design that involves a step-wise sampling ofi primary 

sampling units (PSU’S), physicians’ practices within 

PSU’S, and patient visits within physicians’ practices. 

For 1980 a sample of 2,959 physicians was selected 

from master fdes maintained by the American Medical Association and the American Osteopathic Association. The physician response rate was 77.2 percent. 

Sampled physicians were asked to complete Patient 

Records (figure 1) for a systematic random sample of 

office visits made during a randomly assigned weekly 

reporting period. Telephone contacts were excluded. 

During 1980, responding physicians completed 

46,081 Patient Records, on which they recorded 

51,372 drug mentions. Characteristics 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 the National Center for Health Statistics, was 

responsible for the survey’s field operations. 

For a more detailed discussion of the limitations, 

qualifications, and definitions of the data collected 

by NAMCS, see Vital and Health Statistics, Series 13, 

Number 44. 

Sampling errors and rounding of numbers 

The standard error is a measure of the sampling 

variability that occurs by chance because only a sample, rather than an entire universe, is surveyed. The 

relative standard error of the estimate is obtained by 

dividing the standard error by the estimate itself and 

is expressed as a percent of the estimate. Tables I 

and II apply these measurements to office visits; 

Tables III and IV apply them to drug mentions. 

Estimates 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 from original, unrounded figures and will not 

necessarily agree precisely with rates or percents 

calculated from rounded data. 

Table 1. Approximate relative standard errors of estimated number 

of office visits based on all physician specialties NAMCS, 1980 

Relative 

Estimated number of office standard 

visits in thousands error in 

percent 

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

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

2,000 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14.1 

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 table: An aggregate of 75,000,000 visi~ hes a 

relative standard arror of 4.7 percent or a standard arror of 3,525,000 

visie (4.7 percent of 75,000,000). 
10 

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

Base of percent 

Estimated percent 

(number of office visits in thousands) 1 or 99 5 or 95 100r90 20 or 80 30 or 70 50 

Standard error in percent 

500 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.7 5.9 8.1 10.8 12.4 13.5 

1,000 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.9 4.2 5.7 7.6 8.7 9,5 

2,000 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.3 2.9 4.0 5.4 6.2 6.7 

5,000 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0.8 1.9 2.6 3.4 3.9 4.3 

10,000 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0.6 1.3 1,8 2.4 2.8 3.0 

20,000 . . . . . . . . . . . . . . . . . . . . . . . . ! . . . . . . . . . . . 0.4 0.9 1,3 1.7 2.0 2.1 

50,000 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0.3 0.6 0.8 1.1 1.2 1.3 

100,000 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0.2 0.4 0.6 0.8 0.9 1.0 

500,000 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0.1 0.2 0.3 0<3 0.4 0.4 

Examole of use of table: An estimate of 30 percent based on an aggregata of 15,000,000 visits has a standard error of 2.4 nercent. or a relative 

stendard error of Spercent (2.4 percent +30 percent). 

Table Ill. Approximate reletive standard errors of estimated number 

ofdrugmentions based onall 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 

20,000 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8.2 

50,000 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6.8 

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

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

650.000 . . . . . . . . . . . . . . . . . . . . . . .. s........ 5.7 

Exampla of usa of table: An aggregate estimate of 75,000,000 drug 

mantions has arelative standard error of 6.5parcent ora standard error 

of4,875,000 mentions (6.5 percent of 75,000,000). 

Definitions 

An ambulatory patient is an individual seeking 

personal health service who is neither bedridden nor 

currently admitted to any health care institution on 

thepremises. 

A physician eligible forNAiVCS is a duly licensed 

doctor ofmedicine or osteopathy currently in officebased practice whose primary job is caring forambulatory patients. Excluded from NAMCS are: physicians who are hospital based; physicians who 

specialize in anesthesiology, pathology, or radiology; 

physicians who are Federally employed; physicians 

who treat only institutionalized patients; physicians 

employed full time by an institution; and physicians 

who spendno time seeing ambulatory patients. 

An office is a place that the physician identifies 

as alocation forhis ambulatory practice. Responsibility overtime for patient care and professional services 

rendered there generally resides with the individual 

physician rather than aninstitution. 

A visit is a direct personal exchange between an 

ambulatory patient andaphysician ora staff member 

working under the physician’s supervision, for the 

purpose of seeking care or 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. 
admceda 11 

Table IV. Approximate standard errors of percents of estimated numkers of drug mentions based on all physician specialties NAMCS, 1980€

Base of percent 

Estimated percent 

(number of drug mentions in thousands) 1 or 99 5 or 95 10 or 90 20 or 80 30 or 70 50 

1,000 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.7 5.8 

2,000 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.9 4.1 

5,000 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.2 2.6 

20,000 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0.6 1.3 

100,000 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0.3 0.6 

600,000 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0.1 0.2 

Standard error in percentage points€

8.0 10.7 12.2 13.3€

5.7 7.6 8.7 9.4€

3.6 4.8 5.5 6.0€

1.8 2.4 2.7 3.0€

0.8 1.1 1.2 1.3€

0.3 0.4 0.5 0.5€

Exampla of use of table: An astimata of 30 parcent based on an aggregate of 12,500,000 drug mentions has a atanderd error of 4.1 percant or a 

ralativa standard error of 13.7 parcent (4.1 percent + 30 percent). 
12
 . 

Recent Issues of Advance Data From Vital and Health Statistics 

No. 80. Medication Therapy in Office Visits for Hypertension: No. 77. 1980 Summary: National Ambulatory Me@ical Care 

National Ambulatory Medical Care Survey, 1980 (Issued: Survey (Issued: February 22, 1982) 

No. 79. Blood Lead Levels for Persons 6 Months-74 Years of No. 76. Blood Carbon Monoxide Levels in Persons 3-74 Years 

Age: United States, 1976-80 (Issued: May 12, 1982) of Age: United States, 1976-80 (Issued: March 17, 1982) 

No. 78. Drugs Most Frequently Used in 0ffice4iased Practice: 

National Ambulatory Medical Care Survey, 1980 (Issued: May 

., 

12, 1982) 

., 

SUGGESTED CITATION 

National Center for Health Statistics, H. Koch: 

Drug utilization in office practice by age and sex 

of the patient: National Ambulatory Medical Care 

Survey, United States, 1980. Advance Data From 

Vita/ and Health Statistics, No. 81. DH HS Pub. No. 

lPHS) 82-1250. Public Health Service, Hyattsville,


Md.


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