recording of drug prescriptions in the county of jämtland, sweden : pattern of drug usage in 16600...

Acta Med Scand 202: 24 1-251, 1977

Recording of Drug Prescriptions in the County of Jamtland, Sweden

Pattern of Drug Usage in 16600 Individuals during 1970-75

G. Boethius

From the Department of Medicine, Ostersund Hospital, Ostersund, and the Department of Clinical Pharmacology, Karolinska Institutet, Huddinge Hospital, Huddinge, Sweden

ABSTRACT. The pattern of drug usage as obtained from a continuous recording of prescriptions in the county of Jiimtland, Sweden, is described. Of 16 600 persons monitored, about 60 % purchase prescription drugs every year. Considering all drugs, 55 % of the patients make 4 purchases or less and 21 % 10 purchases or more (mean 6.2 for men, 7.1 for women). A small portion (4%) of the patients accounts for 20 % of the total prescriptions and 21 % of the total costs. The six largest pharmacologic groups of drugs, antimicrobials (prescribed to 21 % of the population), analgesics (19 %), psychotropics (18 %), drugs used in respiratory diseases (15 %), cardiovssrular (14 %) and gastrointestinal drugs (13 %), constitute 67 % of total purchases and 73% of total costs. Evidence for the representative nature of the recorded data is presented. Women dominate in all age groups except the youngest and in all main groups of drugs. Although exposition to drugs generally increases markedly with age, prescriptions of antiallergic and ear, nose and throat drugs decrease with increasing age. As the indication for the prescription is not recorded, the relationship between prescription and incidence of disease is clear only for drugs used for a single indication, e.g. antidiabetics. With the exception of drugs such as antidiabetics, cardiac glycosides and antihypertensives, there is a marked fall in prescribing during the summer. Every year 50% of the patients receive prescriptions from one physician only, while 1% obtain drugs from 7 or more doctors. Physicians outside the county hospital (30 % of total) issue 74% of the total prescriptions. The total number of prescribed drug specialities has been little affected by the recommendations from the Drug Committee of the county but the number of recommended drugs which were prescribed by many physicians increased from 1972 to 1975. In the case of serious adverse drug reactions, the data will provide

information on the number of patients exposed to the drug, the duration of exposure and the number of physicians who prescribe the drug. At the time of its withdrawal from the market, practolol had been prescribed to 112 of the monitored individuals, who could have been reached for follow-up if necessary. Seven of the 33 physicians prescribing the drug issued their first prescription after the manufacturer’s preliminary warning about side-effects.

Since 1970 outpatient prescriptions dispensed to 1 I7 or 16600 of the inhabitants in the county of Jamt- land, Sweden, have been continuously recorded (12). Analysis of the data obtained so far includes the pattern of drug usage in various groups of patients or individuals such as pregnant women and blood donors (6,7,8,9). The longitudinal design of the project has also permitted follow-up studies of drug usage (1 1).

The purpose of this paper is to further illustrate the. kinds of data which can be derived from this project. Emphasis will be put on information which cannot be obtained from drug sales statistics or prescription studies based on non-identifiable sam- ples.

MATERIAL AND METHODS The basic methodology used to obtain prescription data as well as the geographical conditions and health care structure in the county of Jamtland have been presented elsewhere (12). Since 1970 about 16600 persons have been monitored. This corresponds to all individuals born on the same four days in each month. Data from prescriptions filled at the pharmacies are continually compiled in drug lists. These contain the patient’s identity number (denot- ing e.g. age and sex), the year and week the drug was

16-772984 Aclir Mt-d Scund 202

242 G. Boethius

Table I. Distribution of main pharmacologic drug groups in 1974 by percentages of population with at least one purchase, of total purchases, of total cost

% of % of % of popula- total total

Drugs tion purchases cost

Antimicrobial Analgesic Psychotropic Respiratory Cardiovascular Gastrointestinal Vitamins Antiallergic Ear, nose and throat Dermatologic Gynecologic Hematologic Ophthalmologic Endocrinologic Electrolytes Other Total

20.9 19.0 18.0 15.0 14.4 13.4 11.7 11.5 10.4 9.1 7.1 6.8 5.2 4.1 3.4 3.3

61.6

8.3 13.0 11.7 10.6 15.9 11.6 8.1 6.0

14.3 24.2 8.2 7.2 4.8 3.4 4.1 2.7 3.2 1.1 3.8 3.8 3.1 3.3 2.4 2.5 2.9 1.6 3.9 5.9 1.6 1.1 3.7 2.0

100.0 100.0

purchased, the prescribing doctor, the total amount and dosage of the drug and the type of prescription record. The indication for the prescription is not available. Drugs obtained without prescription are not recorded.

Variables studied in this survey include: Number of individuals (patients). Monitored population in 1970: 8471 men, 8071 women; in 1974: 8535 men, 8 194 women. In the 5-year period 1970-74, 10213 men and 9750 women included in the study resided in the county (12). Number of purchases. Dispensed or refilled prescriptions. Number of defined daily doses (DDD) (5). DDD is the agreed average dose used for the main indication of a drug, e.g. 40 IU insulin, 1.5 g tolbutamide, etc. (1). Number of specialities. The about 1800 drugs registered in Sweden have different formulations (tablets, solution, etc.) and strength, making up a total of 2 844 specialities in 1970 and 2 618 in 1974. Number of physicians. The prescribing doctor is coded not as an individual but as the holder of a post, e.g. resident in the Department of Medicine. Since there is often more than one post of a kind at each clinic, the number of prescribing physicians may be underesti- mated. Cost caicuiated as whoiesale price at the pharma- cy. The true cost for the patient and for society has not been considered in this study. 1 Sw. cr. a0.25 US$. Sea- sonal variation in purchases. The ?-test was used to determine the significance of the variation between 13 4-week periods. Drug safes data, which include sales to hospitals (10-15%), have been obtained from Liike- medelsstatistik AB (Swedish Pharmaceutical Data).

The Drug Committee of the county of Jiimtland origi- nates from the hospital-centered committee formed in 1967. Since 1972 it covers the whole county and issues a drug formulary, “Z liikemedel”, which is revised yearly. This formulary lists about 300 drugs recommended for use unless the conditions of the individual patient indicate otherwise.

RESULTS What drugs are prescribed? The prescription of the main pharmacologic groups of drugs is presented in three ways in Table I. Evidently, the rank order of the individual drug groups varies with the mode of measurement. The six largest groups are prescribed to 13-21 % of the population and constitute 66.5 % of total purchases and 72.6% of total costs. In adults, almost 3/4 of all drug purchases concern psychotropics, cardiovascular drugs, analgesics, antimicrobials, drugs used in respiratory diseases and gastrointestinal drugs (Fig. 1). In young ages, drugs used in ear, nose and throat disorders, allergy and gynecologic conditions are quantitatively important.

To whom are drugs prescribed? Age and sex distributions of persons obtaining drugs are presented in Fig. 2. In general, drug exposition increases markedly with age (Fig. 2a) . In some drug groups, like antiallergic and ear, nose and throat drugs, there is a decrease with increasing age (Fig. 26) . Other groups, such as dermatologic drugs, respiratory tract agents and antimicrobial drugs, are rather evenly prescribed in all ages (Fig. 2c) . The majority of drugs, though, increase in use with advancing age (Fig. 2d) . Women dominate in

Psychotropic

Card.varc.

Anslgosica Ant i m i c r o b i a l Rosp i rs tory bast ro - i n t o a t .

Other drugs

Psychotropic

Csrd.vaac.

Analgo$ i c r A n t i m i c r o b i a l R e s p i r a t o r y 6sr t ro - i n toe t . Othor drugs

10 2b 30 i o so $0 i o eb b 8 1; is i s i s s’s ds i s ‘‘9.

Fig. 1 . Distribution of drug groups within each age interval in 1974. (a) Men, ( b ) women.

Acra Med Scand 202

Recording of drug prescriptions 243

' c . 0

H

A l l drugs 1974 I

-men .... women

..... ..... ........ _/ ...................... .................. "\ __.'. ............ . - /

c 0

Y

rl

.- a

5 20- a r 0 -

w

-men ..... women

40- c 0

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4

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r 0 -

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0 4 . . . . . . . . . ? 1,O 2,O 310 4,O 5,O 6,O 8,O a 9 I 9 29 39 49 59 69 79

Age

Ear-nose-throat drugs 1974

-men women

E

- men ........... .... women

............ n

C 0

c a rl 3

0 0

.- 40-

n -

: 0: w 4 1,O 2,0 3,O 4? 5,O 6,0 7,0 8,O b 9 19 29 39 49 59 69 79

Age

A n t i a l l e r g i c drugs 1974 C 0 - men .-

-men women

.......... -._.

..- .._..

L I - 0

w 0 4 t,O 2,0 3,O 4,O 5,O 6,0 7,O B,O b 9 19 29 39 49 5 9 69 79

A V

Oermrtologic drugs 1974 C

.... women ........................................

w p 1,O 210 3,O 4,O 5,O 6,O 7,0 0: C 9 19 29 39 49 5 9 69 79

Age

R e s p i r a t o r y t r r c t agents 1974

- men .............

. . . . . . . . . $I 1: 2,0 3,O 4,O 5: 6,O 7: 8,O 9 19 29 39 49 5 9 69 79

H

C Age

Fig. 2. Proportion of population with drug purchases in 1974. (a) AU drugs, ( 6 ) drugs decreasing with age, (c)

A n t i m i c r o b i a l drugs 1974 1

a

-men

. . . . . . . p 1,O 2,0 3,O 4,O 5,O 6: 7,O 8: 0 4 . .

d 9 19 29 39 49 59 69 79

Age 1 Psychotropic drugs 1974

0 4 . . . . . . . . . ? i,o 2p 3p 4p 5p 6p 7p ep d 9 19 29 39 49 59 69 79

Age

Cardiovascular drugs 1974

20: 0 p 9 l1O 19 2,O 29 3,O 39 4,0 49 5,O 59 69 6,O 7: 79 8,O

d Age

drugs rather evenly prescribed in all ages, ( d ) drugs increasing with age.

Acta Med Srand 202

244 G. Boethius

60 -

c 4 0 -

8 rl

a n -

a

0 2 0 -

0

*-

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.-

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(1

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.-

a

0

$..

h

- male f e m a l e

04 . 0-4 5-9 10-14 15-19

Age

0 0 - 4 5-9 10-14 15-19

Age

Fig. 3. Proportion of population aged &I9 with purchases of ( ( I ) drugs used in urinary tract infection, and (b ) psychotropic drugs in 1974.

all age groups except the youngest and in all main groups of drugs. In young people, purchases of some drug groups

show a marked increase in females 15-19 years of age (Fig. 3). The rise in psychotropic drugs is mainly attributed to benzodiazepines and combina- tions of barbiturates and belladonna alkaloids.

In drug groups used mainly for a single indication the frequency figures may give an idea of how common a disease, condition or symptom is in the population at various ages (Fig. 4). Due to the longitudinal design of the study and the monitoring of de-

v- 0 2 1

/-

M

0 1,O 2,O 3,O 4,0 5,O 6,0 7,Q 8,O

9 1 9 29 39 49 5 9 69 79

Age

Fig. 4. Proportion of population with purchases of antidiabetic agents in 1974.

40

C 0

* I r(

.-

20 a r 0

W

0

wommn 1 --en

1970-

9 1: 2? 3? 4; 5; 6? 70 8: 9 1 9 29 39 49 5 9 69 7$

74

I I 1970-74

1974

--awn 1 women

. , . , . . , , 7 1? 2? 3,0 4,O 5? 6,0 7,O 8,O 9 19 29 3 9 49 59 69 7 9

Age

Fig. 5. Proportion of population with purchases of ( a ) drugs used in urinary tract infection, and ( b ) psychotropic drugs in 1974 and in the 5-year period 1970-74.

fined individuals, it is possible to state not only how many persons are exposed to drugs in one year, but also to find out the proportion of the population exposed during longer periods. In most drug groups the 5-year cumulative number of exposed individuals is 2-3 times greater than the number in a single year (Fig. 5) .

How many drug purchases are made? The cumulative number of prescriptions dispensed per individual in one year (1974) is seen in Table 11. Considering all drugs, 5 5 % of the patients made 4 purchases or less, while 21 % made 10 purchases or more (mean 6.2 for men, 7.1 for women). In a group like cardiovascular drugs, representing mainly chronic treatment, a greater number of prescriptions (men 4.3, women 3.9) are dispensed to the average patient compared with occasional, short- term treatment with antimicrobials (men I .6, women 1.7 purchaseslyear). Psychotropic drugs rep- resent an intermediate group with no difference between the sexes (men 3.7, women 3.6).

Aclu Med Scand 202


Table 11. Number of purchases per individual in 1974. Cumulative distribution (%)

Cardiovascular Antimicrobial Psychotropic All drugs drugs drugs drugs

No. of purchases Total Men Women Men Women Men Women Men Women

1 2 3 4

(5-1 9 (10-)14 (15-1 19 (20-)24 (25-)29 (30-)91

18.6 21.1 16.7 34.0 37.4 31.2 45.5 48.8 42.8 54.5 57.7 51.8 78.7 81.3 76.4 88.9 90.1 87.9 93.7 94.4 93.0 %.3 %.7 95.9 97.8 97.9 97.7

100.0 100.0 100.0

28.2 28.6 42.4 46.5 54.6 59.2 65.5 69.6 90.5 92.5 97.6 98.5 99.5 99.4 99.7 99.8 99.9 99.9

100.0 100.0

67.5 61.9 42.1 41.8 87.9 84.8 59.0 59.5 94.5 93.6 70.1 69.3 96.8 %.3 75.9 78.6 99.8 99.9 91.8 92.2 99.9 100.0 %.8 96.7

100.0 98.6 98.7 99.4 99.3 99.5 99.5

100.0 100.0 Average per person 6.7 6.2 7.1 4.3 3.9 1.6 1.7 3.7 3.6

High consumers In 1974,3.7% of the patients obtained more than 24 prescription drugs. The purchases of this group of patients represented 20% of the total amount and 21 % of the total cost of drug treatment in the county. Some characteristics of this group are given in Table 111. Psychotropic drugs seem to compose a greater part (23 %) of their purchases compared to the population as a whole (16%).

Who prescribes drugs? Every year 50% of the patients receive prescriptions from one physician only, while 1 % visit 7 doctors or more (Table IV). The average number of physicians per male was 1.8, per female 2.0 in 1974. The pattern for some drug groups representing chronic and/or acute treatment is also seen in Table IV.

Hospital physicians, making up 70% of the total number of physicians in the county, were responsible for 26% of the outpatient prescriptions in 1975. Physicians outside the hospital, i.e. district physicians (22 %) and private practitioners (8 % of total doctors), issued 52 % and 22 % of the prescriptions, respectively. The distribution within some drug groups between the physician categories is shown in Table V.

What doses are prescribed? A study of the variability of prescribed daily doses and dosage intervals in relation to pharmacokinetic principles is published elsewhere (10).

The cost of prescribing The cost per prescription differs somewhat with age and sex (Fig. 6). As the number of prescriptions per individual increases with age, the individual cost also shows a maximum in older age.

The prescribing cost differs somewhat between physician categories (Table VI). In prescriptions issued by hospital physicians, especially those in surgery and pulmonary medicine, there is a pro- nounced sex difference, male purchases being more expensive than female.

Seasonal variation in prescribing The seasonal variation in prescribing arises mainly from the morbidity pattern and vacation activities. Considering all drugs, there is a marked fall in the

Table 111. Characteristics of individuals with more than 24 prescription drug purchases in 1974

Individuals with >24 purchases

% of purchasing N total individuals

All

No. of individuals No. of purchases Cost (Sw. cr.)

Total Per purchase Per person

Females (%) Aged g j e a r s

or more I[%) Average no. of prescribing physicians

384 3.7 10 305 13 493 19.6 68 785

388 339 20.5 1894 342 29 28

I011 I84 60 55

64 29

4.3 1.9

Actti Med Scarid 202

246 G. Boethius

Table IV. Number of prescribing physicians per individual in 1974. Cumulative distribution (%)

Cardiovascular Antimicrobial Psychotropic All drugs drugs drugs drugs

No. of physicians Total Men Women Men Women Men Women Men Women

1 50.0 55.3 45.5 2 76.2 79.8 73.1 3 89.7 91.5 88.1 4 95.4 %.I 94.7 5 98.0 98.4 97.6 6 99.1 99.1 99.1 7 99.6 99.6 99.6 8 99.8 99.8 99.8 9 99.9 99.9 99.9

(10-)13 100.0 100.0 100.0 Average per person 1.9 1.8 2.0

57.9 62.2 81.4 78.8 84.3 87.1 %.2 94.9 95.4 %.6 99.1 99.1 98.3 98.7 99.8 99.8 99.4 99.7 r00.0 100.0 99.8 99.9

100.0 100.0

1.7 1.6 1.2 I .3

66.9 66.7 86.7 87.4 95.7 95.0 98.6 97.9 99.4 99.1 99.7 99.5

100.0 99.7 99.8 99.9

100.0

1.5 1.5

Table V . Distribution (%) of drug prescriptions and cost between physician categories in I975

A. Internal B. All hospital C. District D. Private Total medicine physicians physicians practitioners (B-D)

Drugs Cardiovascular Gastrointestinal Antimicrobial Vitamins Endocrinologic Psychotropic Analgesic

15.4 24.0 60.5 15.5 100.0 5.4 18.7 59.3 22.0 100.0 2.7 22.4 58.3 19.3 100.0 3.8 23.9 44.3 31.8 100.0

26.9 46.8 42.1 11.1 100.0 5.4 29.9 45.0 25.1 100.0 3.2 17.9 54.2 27.9 100.0

All 6.7 26.2 52.2 21.6 100.0 Cost of drugs prescribed by each category (%) 10.6 29.7 49.8 20.5 100.0

Physicians in each category (%) 8.3 69.5 22.2 8.3 100.0

number of prescriptions dispensed to county residents during the summer (p<O.Ool), compensated to some extent by an increase in drug purchases by tourists (p<O.Ool) (Fig. 7a) . No significant seasonal variation is noted in some drug groups mainly representing chronic treatment, such as antidiabetics, cardiac glycosides and antihypertensives. This also applies to drugs used in urinary tract in- fections (sulfonamides , nitrofurantoin, nalidixic acid and methenamine mandelate), while antibiotics and respiratory tract agents, not unexpectedly, show a decrease in summer @<0.001) (Fig. 7b).

A change in indications for the use of a drug may be revealed by the seasonal pattern of prescribing. As expected, a high level of antihistamine use is seen during the season of allergens from trees, flowers and grasses in the 1970 figures (Fig. 8) . During the next few years an increase occurred in the prescribing of the antihistamines cinnarizine

(Rhomar@) and brompheniramine (Lunerin3 for nasal decongestion in common cold. In 1974 the seasonal distribution of these two preparations re- sembles that of other common cold drugs more than that of other antihistamines.

I *._ ... ... , c

I n .- L u U

L e n

o n 1c

C . O 0 .- z+

A D @

Fig. 6. Mean cost per individual (0) and per prescription (0) and mean number of prescription drug purchases per individual (*) in relation to age and sex in 1974.

A r m Med Scand 202


R inomar Q

o o t h e r ant ih is tamines

L a a Lunerin? Rinomar@

2 d 0; i 9 17 25 33 41 49 reek

Fig. 7. Seasonal distribution of (a) prescription drugs dispensed to county residents (0) and non-residents (O), and (6) respiratory tract agents (O), antibiotics (0) and drugs used in urinary tract infection (0) in 1974.

Trends in prescribing New drugs or new indications for drugs already on the market may modify the prescribing pattern. This is clearly illustrated by the sharp increase in the use of preceptor blocking agents during recent years and the concomitant rise in the use of hydralazine in hypertension (Fig. 9).

Clonidine (Catapresan") was introduced as an antihypertensive drug in Sept. 1970 and was used increasingly in the county from March 1971 with the approval of the Drug Committee (Fig. 10). All three parameters of usage (number of purchases, patients and DDD) show, however, a marked decline after 1973, with few new patients being started on the drug.

Table VI. Cost (Sw. cr.) per prescription issued by different physician categories in 1974

Physician category Men Women Total

Internal medicine Pulmonary medicine Surgery Pediatrics Psychiatry Geriatric All hospital physicians District physicians Private practitioners

43 38 41 so 32 43 38 22 29 23 18 20 26 22 24 30 29 30 36 29 32 27 27 27 23 24 24

'c o o t h e r ant ih is tamines

t " . . . . . . . . . , . . ,

1 9 17 25 33 41 4 9 reek Fig. 8. Seasonal distribution of purchases of antihistamines in 1970 and 1974.

Another example is given in Fig. 11. Glibenc- lamide, introduced in Nov. 1971, was 4 years later the most frequently used oral antidiabetic agent in the county. Of the two simultaneously registered preparations, Daonil", having been on clinical trial in the County Hospital, was recommended for use by the local Drug Committee.

I b r t r - b l o c k r r s c a r d i a c glyco- r i d r s

t h i r r i d r r + c h l o r t h r l i d o n r other d i u r r t i c s

.-

51 + - c o r o n a r y a n t i r r r y thm v r s o d i l . i c s .- v-

" ~ . . . . . . a 1910 11 1 2 1 3 1 2 1 5 y r r r

I , h y d r a l r z i n r

c l o n i d i n r

r r u m o l f i r 0 o t h r r r

,1 6 1070 71 72 13 12 15 y r r r

Fig. 9. Prescribing of (a) all cardiovascular drugs, and (6) antihypertensive drugs in 197675.

Acta Med Scand 202

248 G. Boethius

0 0 0-

... 8

1

General effect of local recommendations on prescribing The total number of prescribed drug specialities has been affected little by the recommendations from the Drug Committee, a decline being seen from 728 in 1970 to 705 in 1974. However, in most pharmacologic groups the number of recommended drugs being prescribed by many physicians increased from 1972 to 1975. Still, 45% of all prescribed cardiovascular specialities are used by 1 4

Cardiac glycos ides I 0 1 912

u)

I 0) I I I Ill I V Total a

Lc Analgesics 0 ,

I I I I l l I V Total

Fig. 12. Percentage of prescriptions issued in compliance with the recommendations of the Drug Committee in 1972 and 1975. Physician category I=internal medicine, / I =all hospital physicians, III=district physicians, IV=private practitioners.

level of compliance. With regard to analgesic drugs, on the other hand, with 10 times as many specialities as in the cardiac glycoside group, there is a small decrease in the proportion of prescriptions of recommended preparations. A lower level of compliance among physicians outside the hospital is seen in most pharmacologic groups.

physicians only (Table VII). Compliance with the recommendations differs with drug group and physician category (Fig. 12). In the cardiac glycoside group, a trend towards uniformity in prescribing is seen among all physicians regardless of

Effect of warnings of side-effects The fall in the use of rauwolfia derivatives in 1975 illustrated in Fig. 9 was most probably related to the reports in 1974 on a suspected link between long- term reserpine use (in hypertension) and breast

4 . 0 400 100

3.0 300 75

2.0 200 50

1.0 100 25

0 0 0

Daon i 1 2 5

-.

1971 7 2 7 3 74 i 5

cancer. In Oct. 1974 a recommendation was issued by the Swedish health authorities to restrict the use of these drugs.

A more detailed example is given in Fig. 13.

Table VII. Percentage of all prescribed cardiovascular specialities being used by variorrs num- bers of physicians in 1972 and 1975

% of prescribed drug specialities

No. of prescribing physicians 1972 I975

Year 1 4 45 45

Fig. I I . Prescribing of two glibenclamide preparations 5-19 41 28

100 100 daily doses, number of purchases and number of patients on drug. Symbols as in Fig. 10.

(Daonil", Eugluconm) measured in, number of defined 204112) 14 21 ~ ~ ~ a l

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1 2 3 4 5 6 7 . 1 1 1 1 1 1 1 ,

C (II

0

2, r

.- 40 .;

20 ," 0

o d z 11 3 3 4 9 13 29 45 9 meek

+ .P I

C

n n - fl 0

2, r

40 .;

20 ," 0

o d 5 11 3 3 4 9 13 29 45 9 meek

1973 1974 1975

Fig. 13. Number of dispensed prescriptions of practolol (bars) and cumulated number of prescribing physicians (curve). Arrows indicate data for registration of drug (I), drug information in county by manufacturer (2), evalua- tion of drug in Swedish medical press (3). letters to physicians from manufacturer about adverse effects (4-3, information about adverse effects and recommendations from Swedish Adverse Drug Reaction Committee (6) . withdrawal of drug (for oral use) (7).

Practolol, a cardioselective preceptor blocking drug, was registered in April 1973, and four months later prescribing started in the county. Coinciding with the first reports to physicians about ocular and cutaneous side-effects, the prescribing curve level- led off and, after recommendations to restrict its usage, fell drastically. There was no significant increase in the proportion of refill dispensations after the warnings and thus no indication that the patients themselves were mainly responsible for continuing treatment. On the contrary, 7 of the 33 physicians prescribing practolol issued their first prescription after the preliminary warning from the manufacturer. Altogether 112 patients (850 when ex- trapolated to the whole county population) were exposed to the drug before it was withdrawn 2 years after its introduction.

DISCUSSION

An important question is whether the county of Jamtland is representative of the country as a whole as far as drug prescription is concerned. For several important drug groups there is good agreement between the prescription data in the county on the one hand and wholesale figures for the whole of Sweden as well as for the county on the other (Fig. 14). Within individual drug groups, differences are found depending on local traditions in prescribing (Table VIII).

Data from a 1/288 sample of all prescriptions in Sweden (13) also confirm the representative nature

Prescr ibed i n county o f

Sales i n Sweden 8 Sales t o )Jamt l a n d

c a r d i a c bet.- hypoten-

Fig. 14. Comparison between prescription data and sales data in 1974. "Sales in Sweden" figures include sales to hospitals (1045%).

glycos ides b lockera s ives

of the Jamtland figures as regards the distribution between the main pharmacologic groups. The level of prescribing in the county seems to be slightly lower than in the country as a whole, 4.2 against 4.7 prescriptions per inhabitant.

In a similar project in Tierp, a more southern area of Sweden (4), a slightly higher prescription rate than in Jamtland was found in 1972 for respiratory tract agents, cardiovascular drugs, vitamins and psychotropics, while the reverse was observed for antihistamines. In 1975 the differences were smaller with the exception of cardiovascular drugs (14).

Prescribing in the county of Jamtland thus seems to be comparable to that in the country as a whole. As has been shown above and in other studies ( I 1 ), drug sales figures expressed in DDD often agree satisfactorily with variables such as number of purchases or number of tablets prescribed. In other instances, knowledge of the individual use of drugs

Table VIII. Number of defined daily doses (DDD) of Preceptor blocking agents sold in Jamtland and the whole of Sweden in 1974

~

Jamtland Sweden DDD

Drug (mg) No. % No. "2

Alprenolol 300 5.7 24.2 10.1 44.1 Propranolol 160 15.1 64.3 11.0 48.1 Practolol 300 2.6 11.1 1.4 6.1 Pindolol 15 0.1 0.4 0.4 1.7 Total 23.5 100.0 22.9 100.0

250 G . Baethius

in a defined population is desirable or necessary. A most important measurement for medical purposes is the proportion of the population exposed to cer- tain drugs.

There have been small changes from 1970 to 1974 in the prescription of the main pharmacologic groups. Psychotropic drugs have decreased their share, with a corresponding increase of 2-3% in cardiovascular and antihistamine drugs.

Whether the level of prescribing is rational cannot be judged from these prescription figures alone. Other investigations based on our data illustrate this fact (6, 11). Moreover, it is not known to what extent the drugs obtained were actually ingested.

As the indication for prescribing is not recorded in this study, the relationship between prescription and incidence of disease may be complex. Excep- tions are drugs used solely for a single indication, e.g. antidiabetics, although not all diabetics are treated with drugs. The prevalence of hypertensive patients on drug treatment, on the other hand, is more difficult to state from our data. To the number of patients using “specific” antihypertensive drugs such as methyldopa or hydralazine should be added an unknown proportion of patients on diuretics and @receptor blocking agents, which are used on other indications as well (6). In a Swedish population study in 1968-69 on 1462 women aged 38-60 years (2), 64% of those treated with diuretics stated that they were prescribed for hypertension (3). With regard to preceptor blocking drugs in Jamtland, it may be noted that 3040% of the patients are on doses usually used in hypertension.

Even with these limitations, the rough prevalence figures obtained on morbidity may be of value for the planning of health services, such as the organi- zation of specialized (outpatient) clinics for hypertension or diabetes or setting up new methods for drug analysis in body fluids. Other potential uses of the prescription data have been discussed elsewhere (12).

The prescribing pattern of different physician categories naturally reflects the morbidity pattern of the diseases they are treating. The sex ratio and mean age (4446 years) of their patients do not differ significantly between hospital physicians, district physicians and private practitioners. The more expensive prescriptions to men issued by physicians in e.g. internal medicine, pulmonary medicine and surgery, are all attributed to the age groups above 40 years. Cardiovascular drugs to these men

are more expensive than drugs prescribed to women. The prescribing of expensive antituberculous drugs almost exclusively to men and the surgeons’ prescriptions of hormones to patients with prostatic carcinoma explain the sex difference in drug cost.

The lower level of compliance with local drug committee recommendations among physicians outside the hospital is not unexpected since the drug committee up till recent years was active mainly among hospital physicians. Knowledge of the prescribing habits in the county is fundamental for the local drug committee in several ways. First- ly, the local tradition in prescribing will influence the choice between two or more preparations otherwise considered equivalent. The presciption data will tell whether one doctor is responsible for most of the prescriptions or several doctors occa- sionally prescribe the drug in question. Secondly, the effects of the recommendations of the prescribing pattern can be followed. Thirdly, knowledge about local habits of prescribing may help to design relevant training programs in pharmacotherapeutics for physicians.

In the case of serious adverse drug reactions, our data will provide information on the number of patients exposed to the drug, the duration of exposure and the number of doctors who prescribe the drug. These variables may also be followed in an attempt to measure the effect of national information pro- gram on side-effects. The main reason for storing data on fully identifiable individuals for long periods is the desirability of being able to follow up potential late effects of any drug. This should be in the interest of the individual as well as society.

ACKNOWLEDGEMENTS The project is sponsored by grants from the National Corporation of Swedish Pharmacies and the County Council of Jamtland.

REFERENCES Baksaas-Aasen, I., Lunde, P. K . M., Halse, M., Halvorsen, I. K. , Skobba, T. J. & Stremnes, B.: Drug dose statistics. List of defined doses for drugs registered in Norway. Edited by Norsk Medisinaldepot, Oslo 1975. Bengtsson, C.: Ischaemic heart disease in women. Acta Med Scand (Suppl) 549: 43, 1973. - Personal communication. Berfenstam, R. & Smedby, B.: Sjukvtirdskonsumtion i Tierpsomddet 1971 (English summary). SPRI rap- port 9, 1974.

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5. Bergman, U., Elmes, P., Halse, M., Halvorsen, T., Hood, H., Lunde, P. K. M., Sjoqvist, F., Wade, 0. L. & Westerholm, B.: The measurement of drug con- sumption. Drugs for diabetes in Northern Ireland, Norway and Sweden. Eur J Clin Pharmacol 8:83, 1975.

6. Boethius, G.: The treatment of hypertension- analysis of drug prescription data. Acta Med Scand (Suppl) 602: 120, 1976.

7. - Recording of drug prescriptions in the county of Jamtland, Sweden. 11. Drug exposure of pregnant women in relation to course and outcome of pregnan- cy. Eur J Clin Pharmacol. In press 1977.

8. - Recording of drug prescriptions in the county of Jamtland, Sweden. 111. Drugs presented for blood donors during a 5 years' period. Eur J C h Pharmacol. In press 1977.

9. Boethius, G., Nordgren, L. & von SchCele, C.: A five-year survey of purchases of antacids, anti-

cholinergic, and psychotropic drugs. J Psychosom Res. In press 1977.

10. Boethius, G. & Sjtiqvist, F.: Doses and dosage intervals of drugs-clinical practice versus pharmacokinetic principles. Clin Pharmacol Ther. To be published.

11. Boethius, G. & Westerholm, B.: Purchases of hypno- tics, sedatives and minor tranquillizers among 2566 individuals in the county of Jamtland, Sweden-a 6 years' follow up. Acta Psychiatr Scand. To be published.

12. Boethius, G. & Wiman, F.: Recording of drug prescriptions in the county of Jamtland, Sweden: I. Methodological aspects. Eur J Clin Pharmacol. In press 1977.

13. Granzell, A., Kristoferson, K. & Wessling, A.: Kontinuerlig kartlaggning av liikemedelskon- sumtionen i Sverige. Svensk Farm Tidskr 79:483, 1975.

14. Smedby, B.: Personal communication.

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