FFh= MPmmT!p d (Q_ d -ed �


From Vital and Health Statistics of the National Center for Health Statistics Number 80. July 22, 1982 

Medication Therapy in Office Visits for Hypertension: 

National Ambulatory Medical Care Survey, 1980 

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

According to data collected by the National 

Center for Health Statistics by means of the National 

Ambulatory Medical Care Survey, patients with essential hypertension made an estimated 25.1 million 

visits to office-based physicians in 1980. During these 

visits there were about 46.5 million mentions of 

drugs, either new or continued, for an average of 1.85 

drug mentions per visit. 

The National Ambulatory Medical Care Survey 

(NAMCS) is a probability sample survey conducted 

annually by the Division of Health Care Statistics of 

the National Center for Health Statistics. The technical notes at the end of this report provide brief information about the source of the data, sampling 

errors, and definitions of terms. A complete description of the survey including limitations and definitions was published in Vital and Health Statistics, 

Series 13, No. 44.1 

Until 1980, an item on the Patient Record form 

(figure 1) indicating whether or not medication 

therapy was offered by the physician was the only 

available information from NAMCS regarding drug 

utilization by office-based physicians. In 1980, the 

item was expanded to include the reporting of specific drugs, prescription or nonprescription, ordered 

or provided by any route of administration during. 

the visit (see figure 1, item 11). The methodology 

used to collect and process this drug information is 

described in Vital and Health Statistics, Series 2, 

No. 90.2 

Data on drugs utilized during visits with essential 

hypertension as the principal (first-listed) diagnosis 

1NationaI Center for Health Statistics, T. Ezzati rmd T. McLemore: The 

National Ambulatory Medical Care Survey, 1977 Summary, United 

States, January-December 1977. Vital and Health Statistics. Series 

13-No. 44. DHEW Pub. No. (PHS) 80-1795. Public Health Service. 

Washington. U.S. Government Printing Office, Apr. 1980. 

2Nationrd 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. Seiies 2-No. 

90. DHHS Pub. No. (PHS) 82-1364. Public Health Service. Washington. 

U.S. Government Printing Office. In press. 

are presented in this report. In order to report accurately what the physician prescribed, drug mentions 

used in this report are based on the physicians’ entries 

on the Patient Record forms. These entries may be 

brand or generic names of prescription or over-thecounter drugs. “Drug mentions” includes all drugs 

listed in item 11, parts a and b. Part b, it should be 

noted, may relate to diagnoses other than hypertension. Therefore, it is assumed that medications 

described in this report were ordered for patients 

with hypertension but may not necessarily be 

therapeutic agents for that condition. 

Medication therapy status and number 

of medications 

During 1980, hypertension was the leading illness–related principal diagnosis and accounted for 

9 percent of all visits. In about 89 percent of these 

visits patients were provided medication therapy 

(table 1). This proportion exceeded the average proportion of drug visits for all diagnoses (63 percent). 

Table 1 shows that a hypertension visit with one drug 

ordered or provided was the most likely event (36 

percent), and proportions of visits decreased as the 

number of drugs increased. This paralleled the average 

prescription pattern shown in figure 2, except that 

proportions of visits for hypertension were higher in 

every category greater than zero. 

Drug mentions r


Table 2 shows the number of visits for hypertension by sex, age, and race of the patient, and by problem status and major reason for the visit. The number 

and percent of visits in which one or more drugs were 

mentioned are shown. These two sets of visit frequencies provide the denominators for the drug mention 

rates (DMR) and the drug intensity rates (DIR). The 

numerator for both rates is the number of all-listed 

U.S. DEPARTMENT OF HEALTH AND HUMAN SERVICES, Public Health Service, Office of Health Research, Statistics, and Technology 
-----

2 

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Ik.$edto ollmr permm m usedf.. ..v OtherDurp.Se Namnd Omwr 10, HealthStatima


1. DATE OF VISIT PATlENT RECORD 

* NATIONAL AMBULATORY MEDICAL CARE SURVEY 

2, :::HOF 3mSEX & COLOR OR RACE 5. ETHNICITY & PATIENT’SCOMPLAINT(S).SYMPTOM(S),OR OTHER 

I � WHITE 

REASON(S)FOR ~VISIT [In patient’s own words] 

2 � BLACK 1 Q HISPANIC a. MOST IMPORTANT 

__.zl_ :::Z 3 �A::!3$FIC 2 � NOT 

Month Day Year HISPANIC b. OTHER 

ORIGIN 

4 HAMERICANINOIAN/ 

ALASKAN NATIVE 

7. MAJORREASON FOR THIS 8 DIAGNOSTICSERVICESTHISVISIT & PHYSICIAN’SDIAGNOSES 

VISITI [Check one] ‘ [Check all ordered or prov6ded] 

1 � NONE 8 DEKG a PRINCIPAL OIAGNOSIS/PROBLEM ASSOCIATED WITH ITEM Sa. 

1 � ACUTE PROBLEM 2 � LIMITEtJ HISTORY/EXAM. 9 QvIsIor4TEsT 

2 � C14RONIC PROBLEM, ROUTINE 3 � GENERAL HLSTORY/EXAM. ,0 OENOOSCOPY 

3 � ckIRON,cpROBLEM. FLAREUp ~ � pAp,EsT 11 � MENTAL STATUS 

4 � pOsTS.RGERY/POm,WURY 5 � CL!NICALUBTEST 

EXAM. b. OTHER SIGNIFICANT CURRENT OIAGNOSES 

,2 (_JOTHER(SPeC,jY) 

* � NoN.1 LLNESS CARE (ROLIT, NE 6 � X-F6AY PRENATAL. GENERAL EXAM., 

WELL BABY, ETC.) 7 � BLOOO PRESSURE CHECK 

10. &~B:::;E7 llm MEDICATIONTHERAPY THISVISIT � NONE 

[Using brand or generic names, record all new and continued mearcations ordered, injected, adtrdiistered, or otherwife 

provided at this vist. Include immunizing and desensitizing agents] 

a. FOR PRINCIPAL DIAGNOSES IN ITEM 93. b. FOR ALL OTHER REASONS. 

,DYES 2DN0 

1. L 

1 

IF YES, FOR THE 

CONOITION IN 2. 2. 

ITEM E%? 

3. 3. 

, � YES 2 � NO 

4. 4. 

12. NON-MEDICATIONTHERAPY 13. WASPATlENT 14m:$K#lll$ttl’K#SIT l& D#RV#ON 

[Chsck all servises o?de?ed or provided this visit] REFERREO 

FOR THISVISIT VISIT 1 � NO FOLLCW-UP PLANNEO BY A=HER [Time asssquy

1 � NoNE 6~OlETCOUNSELlNG PHYSICIAN? 2DR~RNATSPEC[FlEOTlME	 3pent m“th 

physician] 

2DPHYS!OTHERAPY 7 � FAMILy/sOclAL 3 � RETURN IF NEEDE13, P.R.N. 

COUNSELING 

3 � OFFICE SURGERY 

8 n MEOICAL COUNSELING I � YES 4 � Telephone FottJ3w-up pLANNEo 

4 � FAMILY PLANNING 

9DOTHER (SP&-i,,, 5 � REFERREo To OTHER PHYSICIAN 

5 � PSYCHOTHERAPY/ TOREFERRING PHYSICIAN THERAPEUTIC LISTENING ,nNO 6 �RETURNED

7 lJAOMITTO HOSPITAL 

F4n.m 8 � OTHER (Spec(/y) 

“e-e. “c- a /a J-Jo} nssm w. U%nl.lal 

“- . . . . . “-” , “-- ,.?, ? .7, ..-. 

Figure 1. Patient Record from the National Ambulatory Medical Care Survey 
ad-ceda3 

Table 1. Number and percent distribution of office visits for	 essential hypertension, by medication therapy status and number of medications: 

United States, 1980 

Medication therapy status and number of medications 

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

Medication therapy status 

With medication . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 

Withoutmedication . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 

Numberofmedications 

None . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 

1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 

2 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 

3 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 

4	 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 

5ormore . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 

40 

36.9 

35.5 

30 

27.4 

20 

14.2 

10 

0 

Number of Percent visitsin distribution 

thousands 

25.137 100.0 

22,282 88.6 

2,855 11.4 

2,855 11.4 

8,932 35.5 

6,884 27.4 

3,661 14.2 

2,040 8.1 

856 3.4 

Essential 

hypertension 

AH diagnoses m 

None 1 2 3 4 5 6 7or8 

Number of medications 

Figure2. Percent ofo~cevisi* foressential hype~ension and foralIdiagnoses bynumber ofmeti*ions: Unitad States, 1980 
4 

Table2. Number of office visits foressential hypertension, number andpercent ofdrugvisits, andnumkr ofall-listed drug mentions, drug mention 

rate, and drug intensity rate, by selected characteristics United States, 1980 

Selected characteristic 

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

Sex 

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

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

Age 

Under45years . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 

45yearsand over . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 

Race 

White . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 

Black . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 

Other . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 

Problem status 

Newproblem . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 

Oldproblem . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 

Major reason for visit 

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


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


Chronicproblem,flareup . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .


Postsurgery orpostinjury . . . . . . . . . . . . . . . . . . . . . . . . . . . . .


Nonillnesscare . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .


I A visit i~ which orie or more drugs were ordered.


2A11.1isted drugs+ number of visits.


3Al[.listed drugs + number of drug VkitS.


drug mentions. Using for the denominator the total 

number ofvisits for hypertension (25.1 million) and 

for the numerator the total number ofdrug mentions 

during hypertension visits (46.5 million) yields a drug 

mention rate of 1.85 drugs per hypertension visit. 

Using drug visits (22.2 million) for the denominator 

yields a drug interzsity rate of 2.09 drugs perhypertension visit in which a drug was mentioned. While 

the DMR providesan average drug use forhypertension visits, the DIR shows that when patients do receive medication therapy during office visits they are 

likely to receive an average of 2.09 drugs. The DIR 

is always higher than the DMR because itis basedon 

only those visits in which one or more drugs are 

utilized, except in the rare case where drug visits 

equal all visits. The DMRwashigher forhypertension 

than for the average ofalldiagnoses regardless of the 

patient’s age group. As figure 3 shows, the DMRincreased as the age group of the patient with hypertension increased. The curve for all diagnoses shows a 

similar pattern, but the rates for hypertension were 

consistently higher. The DMR was higher for females 

than for males, but other rates detailed intable2 did 

not vary significantly, probably due tothe large sampling error associated with these relatively small 

estimates. 

Office visits AllIisted Drug Drug 

visits visits1 mentions rate per rate per 

(numberin (numberin ‘~,~~ (number in visit2 visi~ 

thousands) thousands) thousands) 

25,137 22,282 88.6 46,484 1.85 2.09 

All Drug Percent drug mention intensity 

15,787 14,203 90.0 30,365 1.92 2.14 

9,350 8,079 86.4 16,119 1.72 2.00 

3,019 2,532 83.9 5,068 1.68 2.00 

22,118 19,750 89.3 41,416 1.87 2.10 

22,048 19,507 88.5 40,965 1.86 2.10 

2,940 2,637 89.7 5,245 1.78 1.90 

�148 ’138 *93.2 *274 * 1.85 + 1.99 

2,155 1,692 78.5 3,380 1.57 2.00 

22,981 20,590 89.6 43,103 1.88 2.09 

1,985 1,611 81.2 3,218 1.62 2.00 

19,209 17,339 90.3 36,471 1.90 2.10 

2,114 1,946 92.1 4,376 2.07 2.25 

*81 *63 *78.6 *197 * 2.43 *3.13 

1,748 1,322 75.6 2,221 1.27 1.68 

Drug status characteristics 

Table 3 provides information about the drugs that 

were utilized for hypertension patients. The entry 

status, or more specifically the physician’s prescribing 

mode, in about 80 percent of the 46.5 million drug 

mentions was the brand name; 18 percent were 

entered by their generic names. An example of the 

former is Hydrodiuril; the latter, hydrochlorothiazide. 

Both entries represent the same drug. The proportion 

designated by brand names during hypertension visits 

(80 percent) exceeded the average of71 percent similarly entered during visits for all diagnoses.3 

Most drugs (92 percent) were prescription drugs 

(Rx) with nonprescription or over-the-counter (OTC) 

drugs accounting for only 6 percent. (Table 4 shows 

that of all drugs entered by brand names, 95 percent 

were prescription drugs and 5 percent were OTC 

drugs.) About 73 percent of the drugs mentioned 

consisted of a single ingredient, suggesting the poten3Natjon~ Centel for He~th Statistics, H. Koch: Drugs most frequently 

used in office-based practice: National Ambulatory Medical Care 

Survey, 1980. Advance Data From Vital and Health Statistics, No. 78. 

DHHS Pub. No. (PHS) 82-1250. Public Health Service. Hyattsville, Md., 

May 13,1982. 
ackmdaa5 

2.0 r


1.9 Essential 

t hypertension

1.8 

t 

1.7 

k 

.E 1.6 

.; 

b 1.5 

Q I 

o~ 

15-24 25-44 45-64 65 years 

years years years and over 

Age of patient 

Figure 3. Drug mention rate per office visit for essential hypertension 

and for all diagnoses, by age of patient: United States, 1980 

tial for ordering by generic name. On the average, 69 

percent of drugs mentioned for all viiits regardless of 

diagnosis were single ingredient drugs. 

Only 6 percent of the total-drug mentions during 

hypertension visits consisted of drugs under the regulatory control of the Drug Enforcement Administration, compared with 9 percent dufing visits for all 

diagnoses. 

Most frequently mentioned drugs 

The 30 drugs listed in table 5 accounted for about 

60 percent of all drug mentions in office visits for 

hypertension. The reader is cautioned that the ranking may be somewhat artificial because some estimates do not differ significantly from other near 

estimates due to sampling variability. 

As may be expected, 2 therapeutic categories, 

hypotensive agents and diuretics, were predominant 

among drug mentions when patients visited for hypertension. (In NAMCS, therapeutic categories were 

based on the classification system of the American 

Hospital Formulary Service.A) Of the 30 listed drugs, 

4Ameficm Society of Hospital Pharmacists, Inc., i’%eA mericanHospital Formulary Service. Washington. Jan. 1980. 

10 are hypotensive agents, 9 are diuretics, 4 are cardiac drugs, and 2 are replacement solutions 

(potassium). Only one is a tranquilizer. 

The most frequently utilized generic substances 

are shown in table 6. The data in this table represent 

the utilization of the generic substance regardless of 

whether the substance was prescribed by brand or 

generic name. The form of use indicates whether the 

substance was used as a single ingredient or in combination with other substances. Hydrochlorothiazide 

(10.5 million) was clearly the most frequently used 

generic ingredient. About 53 percent of its use was 

in combination with other drugs. Some generic drugs 

such as diazepam, digoxin, furosemide, ibuprofen, 

metoprolol, metalozone, nadolol, and prazosin were 

never prescribed in combination with another substance. Others, such as spironolactone and triamterene, were ahnost always found in combination 

prescriptions. 

Additional data on medication therapy in office 

visits for hypertension, as well as for other diagnoses, 

will appear in a future Vital and lifealth Statistics publication. Questions regarding this report may be 

directed to the Ambulatory Care Statistics Branch by 

calling 301436-7132. 

4 
6 admcecw. 

Table 3. Number and percent distribution of all-listed drug mentions in office visits for essential hypertension, and percent distribution for all 

diagnosix, by drug status characteristic= United States, 1980 

All Hypertension diagnoses 

Drug Watus characteristic Numbar in Percent Percent 

thousands distribution distribution 

Total . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46,484 100.0 100.0 

Entry status 

Genericname . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8,495 18.3 24.2 

Brand name . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37,067 79.7 71.2 

Therapeuticeffect . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 649 1.4 3.2 

Undetermined . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . *272 �0.6 1.5 

Prescription status 

Prescription (Rx)drug . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42,664 91.8 82.6 

Nonprescription (OTC)drug . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2,899 6.2 12.6 

Undetermined . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 921 2.0 4.9 

Composition status 

Singleingredient . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34,037 73,2 69.0 

Combination . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11,038 23.8 24.4 

Multivitamin . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . �487 *1.1 2.0 

Undetermined . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 921 2.0 4.6 

Federal corrtrol status 

Controlled . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2,673 5.8 8.6 

Uncontrolled . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42,889 92.3 86.5 

Undetermined . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 921 2.0 4.9 

Table4. Permntdisttibution of brand name drugmentions ino~cevisits forhypetiension bydrug Wauscharactetisti= United States,l98O 

Drug status characteristic 

Percent 

distribution 

Prescription status 

Prescription (Rx)drug . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 95.4 

Nonprescription (OTC)drug . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4.6 

Composition status 

Single ingredient . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 70.9 

Combination . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28.0 

Multivitamin . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ....... 1.1 
admcdaa7 

Table 5. Number and percent distribution of most frequently mentioned drugs in office visits for essential hypertension, described by principal 

generic ingredient(s) and principal therapeutic category: United States, 1980 

Name of drug~ 

All drug mentions . . . . . . . . . . . . . . . . 

Dyezide . . . . . . . . . . . . . . . . . . . . . . . 

Hydrochlorothiazide . . . . . . . . . . . . . . 

Aldomet . . . . . . . . . . . . . . . . . . . . . . 

Inderal . . . . . . . . . . . . . . . . . . . . . . . 

Hydrodiuril . . . . . . . . . . . . . . . . . . . . 

Hygroton . . . . . . . . . . . . . . . . . . . . . 

Lopressor . . . . . . . . . . . . . . . . . . . . . 

LaSix . . . . . . . . . . . . . . . . . . . . . . . . 

Aldoril . . . . . . . . . . . . . . . . . . . . . . . 

Diuril . . . . . . . . . . . . . . . . . . . . . . . . 

Ser-ep-as . . . . . . . . . . . . . . . . . . . . . . 

Aldactezide . . . . . . . . . . . . . . . . . . . . 

Reserpine . . . . . . . . . . . . . . . . . . . . . . 

Apresoline . . . . . . . . . . . . . . . . . . . . . 

Potassium . . . . . . . . . . . . . . . . . . . . . 

Slow-K . . . . . . . . . . . . . . . . . . . . . . . 

Esidrix . . . . . . . . . . . . . . . . . . . . . . . 

Valium . . . . . . . . . . . . . . . . . . . . . . . 

Motrin . . . . . . . . . . . . . . . . . . . . . . . . 

Minipres . . . . . . . . . . . . . . . . . . . . . . 

Corgerd . . . . . . . . . . . . . . . . . . . . . . . 

Lenoxin . . . . . . . . . . . . . . . . . . . . . . . 

lnfksenzavimsveccinetype A,B . . . . . . 

Enduron . . . . . . . . . . . . . . . . . . . . . . 

Cetapres . . . . . . . . . . . . . . . . . . . . . . 

Aspirin . . . . . . . . . . . . . . . . . . . . . . . 

Dioxin . . . . . . . . . . . . . . . . . . . . . . . 

Enduronyl . . . . . . . . . . . . . . . . . . . . . 

Diabtnese . . . . . . . . . . . . . . . . . . . . . 

Vitamin B-12 . . . . . . . . . . . . . . . . . . . 

Residual . . . . . . . . . . . . . . . . . . . . . . 

Number 

in 

thousands 

Percent

distribution Principal generic ingredient 

46,484 100.0 . . . 

2,583 5.6 

2,449 5.3 

2,284 4.9 

2,090 4.5 

1,836 4.0 

1,779 3.8 

1,569 3.4 

1 J25 2.9 

910 2.0 

869 1.9 

7B7 1.7 

786 1.7 

730 1.6 

650 1.4 

644 1.4 

619 1.3 

588 1.3 

578 1.2 

557 1.2 

529 1.1 

479 1.0 

447 1.0 

415 0.9 

402 0.9 

402 0.9 

*362 “0.8 

*353 *0.8 

*344 �0.7 

�319 ‘0.7 

*303 *0.7 

18,496 39.8 

triamterene, hydrochlorothiezide


hydrochlorothiez ide


meth yldopa


proprenolol


hydrochlorothiazide


chlorthalidone


metoprolol


furosemide


methyldopa, hydrochlorothiazide


chlorothiazide


reserpine, hydralazine, hydrochlorothiazide


spironolactone, hydrochlorothiazide


reserpine 

hydralazine 

potassium replacement solution 

potassium replacement solution 

hydrochlorothiez ide 

diazepam 

ibuprofen 

prazosin 

nadolol 

digoxin 

influenza virus vaccine 

methyclothiazide 

clonidlne 

aspirin 

digoxin 

methyclothiazide, deserpidine 

chlorpropamide 

vitamin B-12 

. . . 

Principal therapeutic 

catagory3 

. . . 

diuretics 

diuretics 

hypotensive agents 

cardiac drugs 

diuretics 

diuretics 

hypotensive agents 

diuretics 

hypotensive agents 

diuretics 

hypotensive agents 

diuretics 

hypotensive agents 

hypotensiveagents 

replacement solution 

replacement sohstion 

diuretics 

sedatives or hypnotics 

hypotensive agents 

hypotensive agents 

cerdiacdrugs 

cardiac drugs 

vaccines


diuretics


hypotensive agents


analgesics and antipyretics


cerdiacdrugs


hypotensive agents


anti-diabetic agents


vitamin Bcomplex


. . .


lBa~ed~n thephYsician~entry on the patient Rwordform. Theentry may beabrand organeric name. Inclusion oftradenamasfor identification 

only and doesnotirnply endorsementbythe U.S. Public Health Serviceorthe Departmentof Heelthand HumenSemices 

Zlfonewneric ingredient islisted, theph~icianJs enmyisthe ~nericdrug orthephysician's entiyis aWandname drUgwhich COnsi5* chieflY of a 

single generic ingredient. 

3Based on the classification system of the American Hospital Formulary Service (A. H. F.S.). 

, 
---

8 

Table6. Number andpercent distribution ofdrugs used inoffice visits foressential hypertension by form ofuse, according tomost frequently 

used generic substances: United States, 1980 

Generic substance 

Aspirin . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 

Chlorothiazide . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 

Chlorthalidone . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 

Clonidine . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 

Diazapam . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 

Digoxin . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 

Furosemide . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 

Hydralazine . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 

Hydrochlorothiazide . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 

Ibuprofen . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 

Metoprolol . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 

Methyclothiazide . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 

Methyldopa . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 

Nfetolazone . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 

Nadolol . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 

Prazosin . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 

Propranolol . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 

Rauwolfia . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 

Reserpine . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 

Spironolactone . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 

Triamterene . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 

Symbols 

Data notavailable 

. . . Category not applicable 

Quantity zero 

Number Form of use 

in 

thousands 

Total Single In 

ingredient combinations 

Percent distribution 

730 100.0 65.6 33.4 

1,304 100,0 69.2 30.8 

2,435 100.0 78.5 21.5 

737 100.0 62.4 37.6 

588 100.0 100.0 

800 100.0 100.0 

1,325 100.0 100.0 

1,763 100.0 44.5 55.5 

10,536 100.0 46.8 53.2 

557 100.0 100.0 

1,583 100.0 100.0 

784 100.0 53.8 46.2 

3,410 100.0 68.2 31.8 

405 100.0 100.0 

479 100.0 100.0 

542 100.0 100.0 

2,379 100.0 94.1 5.9 

437 100.0 61.2 38.8 

2,665 100.0 30.7 69.3 

847 100.0 7.1 92.9 

2,612 100.0 1.1 98.9 

0.0 Quantity more than zero but lessthan 

0.05 

z	 Quantity more than zero butless than 

500 where numbers are roundedto 

thousands 

* Figure does not meet standards of 

reliability or precision (more than 

30 percent relative standard error) 

# Figure suppressed to comply with 

confidentiality requirements 

L I 
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 through its National Ambulatory Medical 

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

the contenninous United States by ambulatory patients to nonfederally employed physicians who are 

principally engaged in office practice, but not in the 

specialties of anesthesiology, pathology, or radiology. 

Telephone contacts and nonoffice 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 fdes 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 office 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. 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 in 

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

Number 44. 

Estimates presented in this report differ from the 

estimates reported in the National Medical Care 

Utilization and Expenditure Survey (NMCUES), 

another program of the National Center for Health 

Statistics (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 which collected information on visits to 

physicians’ offices and hospital outpatient departments. 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 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 

statistics are shown in tables I and 111.Standard errors 

for estimated percents of visits are shown in table II 

and IV. Tables I and 11 should be used to obtain the 

standard emor of a specific drug mention (e.g., 

Dyazide). Tables III and IV should be used to obtain 

the 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 origimd, unrounded figures and will not necessmily agree preciseIy with percents calculated from rounded data. 

Definitions i

\ 

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 eligz”blefor NAMCS is a duly licensed 

doctor of medicine (M.D.) or doctor of osteopathy 

(D.O.) currently in office-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 

employed; physicians who treat only instutionaked 

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 location for his ambulatory practice. ResponsibilTable 1. Approximate relative standard errors of estimated numbers 

of office visits based on all physician specialties: NAMC8, 1980 

Relative 

Estimated number of office visits standard 

in thousands error in 

percent 

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

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

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

58000 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9.4 

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

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

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

100,000 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4.5 

550,000 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4.7 

Example of usa of table: An aggregate of 75,000,000 visits has a 

ralative standard error of 4.7 percent, or a standard error of 3,525,000 

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

Table II. Approximate standard errors of percents Of estimated numbars of office visits based on all physician specialties: NAMCS, 1980 

Base of percen t Estimated percent 

(number of office visits in thousands) 1 or 99 5 or 95 10 c-r 90 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 I 

Example of use of table An estimate of 30 percent based on an aggregate of 15,000,000 visits hasastandard error of 2.4percent, or a relative / 

standard error of 8 percent (2.4 percent+ 30 percent). 

ityovertimefor patientcareand professional services 

rendered there generally resides with the individual 

physician rather than an institution. 

A visit is adirect personal exchange between an 

ambulatory patient and aphysician orastaffmember 

working under the physician’s supervision, for the 

purpose of seeking care andrendering 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 spectilcally instructed during the visit to 

continue the medication. 

, 

Table II 1. Approximate relative standard errors of estimated numlx?r 

of drug mentions besed 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 ~ 

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

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

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

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

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

Example of usa of table: An aggregate estimate of 75.000,000 drug 

mentions has arelative standard error of 6.5 percent ora standard error 

of 4,875,000 mentions (6.5 percent of 75,000,00@. 

I 
aklmdaa 11 

TabIelV. Approximate wandard errors ofpercents ofeWimated num&mof drug mentions ksedonall physician specialties NAMCS,1860 

Base ofpercent 

Estimated percent 

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

Standard error in percentage points 

1,000..................................... 2.7 5.8 8.0 ‘10.7 12.2 13.3 

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 mentions hese standard error of 4.1 percant ora 

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


Recent Issues O(Advance Data From Vital and Health Statistics 

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, 1976-1980 (Issued: March 17, 1982) 

No. 78. Drugs Most Frequently Used in Office-Based Practice: No. 75. Expected Principal Source of Payment for Hospital 

National Ambulatory Medical Care Survey, 1980 (Issued: Discharge: United States, 1979 (Issued: February 16, 1982) 

May 12, 1982) 

No. 77. 1980 Summary: National Ambulatory Medical Care 

Survey (Issued: February 22, 1982) 

SUGGESTED CITATION 

National Center for Health Statistics, B. K. Cypress: 

Medication therapy in office visits for hypertension: 

National Ambulatory Medical Care Surveyr 1980. 

Advance Data From Vital and Health Statistics, 

No. 80. DHHS Pub. No. (PHS) 82-1250. Public


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