The impact on community benzodiazepine prescribing of hospitalization

Journal of Psychosomatic Re~earch. Vol. 42, No. I, pp. 61-69. 1997 "opyright © 1997 Elsevier Science Inc. All rights reserved. fX~22-3999/97 $17.00 + .0~1

ELSEVIER

S0022-3999(96)00232-2

THE IMPACT ON C O M M U N I T Y B E N Z O D I A Z E P I N E P R E S C R I B I N G OF H O S P I T A L I Z A T I O N HELEN

L. M I L L A R , * F I O N A S. C L U N I E , * M A R K M. M C G I L C H R I S T , t A L E X D. M C M A H O N t a n d T H O M A S M. M A C D O N A L D t (Received 1 December 1994: accepted 9 July 1996)

Abstract--To assess the impact of both general and psychiatric hospitalization on the community prescribing of benzodiazepines, we carried out an observational study using record linkage of prescribing prior to and following hospitalization along with a review of hospital case records at four Tayside General Practices. In a population of 29,672 subjects, 2628 general hospital and 254 psychiatric hospitalizations were studied. The main outcome measure was the change in community benzodiazepine prescribing following hospitalization. We found that admission to a general hospital resulted in 59 of the 2628 subjects (2.2%) commencing and 45 subjects (1.7%) discontinuing benzodiazepines. Admission to a psychiatric hospital resulted in 17 of 254 subjects (6.7%) commencing and 40 (16.7%) discontinuing benzodiazepines. When compared to benzodiazepine prescribing in the study population these effects were trivial. We conclude that hospitalization in both general and psychiatric hospitals had a minor effect on total community prescribing of benzodiazepines. In this study general hospital admission resulted in a small net increase and psychiatric hospitalization a small net decrease in benzodiazepine prescribing. Copyright © 1997 Elsevier Science Inc. Keywords:

Benzodiazepines; Community: Drug utilization; Hospitalization: Prescribing; Record

linkage.

INTRODUCTION B e n z o d i a z e p i n e s a r e c o m m o n l y p r e s c r i b e d p s y c h o t r o p i c drugs. S o m e 10% of the p o p u l a t i o n a r e using these, t w o thirds of which a r e w o m e n [1]. M o s t b e n z o d i a z e p i n e p r e s c r i b i n g is i n i t i a t e d b y g e n e r a l p r a c t i t i o n e r s [2]; h o w e v e r , p r e v i o u s r e s e a r c h on t h e influence of h o s p i t a l a d m i s s i o n o n b e n z o d i a z e p i n e s has p r o d u c e d conflicting results. S h a n et al. [3] s t u d i e d b e n z o d i a z e p i n e p r e s c r i b i n g to p a t i e n t s w h e n t h e y w e r e in the h o s p i t a l a n d o n h o s p i t a l d i s c h a r g e for all a d m i s s i o n s o v e r a 7 - d a y p e r i o d . N o disc h a r g e p r e s c r i p t i o n s for b e n z o d i a z e p i n e s w e r e i n i t i a t e d f r o m t h e hospital. S u r e n d r a k u m a r et al. [4], i d e n t i f i e d 17 p o t e n t i a l n e w b e n z o d i a z e p i n e users f o l l o w i n g gene r a l h o s p i t a l a d m i s s i o n o v e r a 2 - w e e k p e r i o d . In n e i t h e r o f t h e s e s t u d i e s was a c o m m u n i t y f o l l o w - u p u n d e r t a k e n . E d w a r d s et al. [5] s u r v e y e d all a n x i o l y t i c a n d h y p n o t i c p r e s c r i p t i o n s in a t e a c h i n g h o s p i t a l o v e r 6 w e e k s a n d a c o m m u n i t y follow*Department of Psychiatry, University of Dundee and tMedicines Monitoring Unit, Department of Clinical Pharmacology, Ninewells Hospital & Medical School, Dundee, UK. Address correspondence to: Thomas M. MacDonald, Department of Clinical Pharmacology, University of Dundee, Dundee DDI 9SY, UK. Tel: 01382 632575; fax 01382 644972; e-maiI:T.M.MAC [email protected] 61

62

H.L. MILLAR et al.

up 4 - 8 weeks after discharge. T h e y f o u n d that hospital p r e s c r i b i n g did n o t influence c o m m u n i t y usage; however, there were p r o b l e m s with their m e t h o d of o b t a i n i n g an accurate drug history from patients. A N e w Z e a l a n d study [6] s h o w e d that, in a g e n e r a l hospital i n - p a t i e n t unit, there was a r e d u c t i o n from 23% to 8% in the n u m b e r of p a t i e n t s p r e s c r i b e d m i n o r tranquilizers f r o m a d m i s s i o n to discharge. H o w e v e r , t h e r e was n o c o m m u n i t y followup to discover what h a p p e n e d r e g a r d i n g p r e s c r i p t i o n after hospital discharge. T o clarify the i m p a c t of b o t h g e n e r a l a n d psychiatric hospital a d m i s s i o n s o n comm u n i t y p r e s c r i b e d b e n z o d i a z e p i n e s , we carried out a study which utilized d i s p e n s e d p r e s c r i b i n g data from four practices.

METHOD The study utilized the Tayside Medicines Monitoring Unit (MEMO) record-linkage database, which has been described in detail elsewhere [7]. In brief, MEMO receives all prescriptions for the Tayside area of Scotland after redemption at a community pharmacy. For each prescription, a unique patient identifier, the Community Health Number (CHNo) is allocated. This number is used in all health care transactions in Tayside. The CHNo and prescription details such as drug, dose, number dispensed, dosing instructions, and date are entered onto a database. MEMO also holds CHNo-specific records of all patients in Tayside registered with general practitioners and of all hospitalization in Tayside back to 1980. These data comprise the Tayside portion of the Scottish Morbidity Record 1 (SMR~) data, which records general hospital data, and the Scottish Morbidity Record 4 (SMR4), which records psychiatric hospitalization data. The present study utilized data on dispensed benzodiazepine prescriptions from four Tayside practices. The study utilized data for the 9-month period 1 April 1990 to 31 December 1990 for general hospital admissions and the 2-year 9-month period 1 April 1989 to 31 December 1991 for psychiatric hospital admissions. All hospitalizations that occurred during these periods were assembled. The study period for psychiatric hospital admissions was longer to increase the number of admissions studied. The community use of benzodiazepines 14 days prior to hospital admission and within 14 days after discharge from the hospital was examined for each patient. The maximum duration of dispensing on hospital discharge was 7 days. Four groups of patients were identified:

Group 1: Patients not taking benzodiazepines at the time of hospital admission and who did not receive benzodiazepines within 14 days of hospital discharge. Group 2: Patients receiving benzodiazepines at the time of hospital admission and who did redeem a benzodiazepine prescription within 14 days of hospital discharge. Group 3: Patients who received benzodiazepines at the time of admission but not after discharge from hospital. Group 4: Patients who did not receive benzodiazepines prior to admission to the hospital, but did commence benzodiazepines within 14 days of hospital discharge. The primary hospital case records were examined in those patients who either commenced or discontinued benzodiazepines following hospitalization.

Analyses The data were analyzed using a log-linear model to examine possible associations between the following factors--gender, type of hospital, and benzodiazepine status before and after hospitalization.

RESULTS

Study populations T h e study p o p u l a t i o n consisted of 29,672 patients, 15,190 f e m a l e ( T a b l e 1). Bet w e e n A p r i l 1, 1990 a n d D e c e m b e r 31, 1990, the study p o p u l a t i o n used, for g e n e r a l hospital admissions, 1676 subjects (1200 f e m a l e ) a n d received 7757 p r e s c r i p t i o n s

Female Practices total study population General hospital study population Subjects Prescriptions Psychiatric hospital study population Subjects Prescriptions

Male Practices total study population General hospital study population Subjects Prescriptions Psychiatric hospital study population Subjects Prescriptions

6 26 17 44

5 22 6 39

21 88

8 15 1882

11 33

5 9

1853

2077

121 453

70 270

2248

76 618

44 281

2313

10--19 20-29

1962

0-9

145 627 214 1248

121 489 187 1035

105 375

102 313 2068

60 190

60 170

2192

2089

40-49

2187

30-39

247 1442

160 647

1518

128 860

77 368

1479

50-59

351 2556

259 1189

1545

147 1071

110 520

1301

60-69

341 2615

256 1191

1136

126 711

83 346

786

70-79

229 2032

186 992

640

57 378

39 180

259

80--89

40 380

32 186

106

5 48

29 3

29

90+

1626 11,844

1200 5639

15,190

736 4477

476 2118

14,482

Total

',a#

~..

w

~.

8

e~

~'

Table I.--The population of subjects in the four practices of the study population, the subjects who received any benzodiazepine between April 1, 1990 and December 31, 1990 comprising the general hospitalization study population and the subjects who received any benzodiazepine ~_. between April 1, 1989 and December 31, 1991 comprising the psychiatric hospitalization study population. All three populations are broken down by age and gender. ~.

64

H.L. MILLAR et al.

(5639 to females). Between April 1, 1989 and December 31, 1991, the population used, for psychiatric admissions, 2362 subjects (1626 female) received 16,321 prescriptions (11,844 to females). These data are shown by age and gender in Table I.

Prescriptions dispensed Benzodiazepines were more frequently used as hypnotics (85.6% of dispensed prescriptions) than anxiolytics. Table II shows the drugs dispensed in the community during the two study periods along with the UK prescribing of these drugs in 1989. Table III shows the utilization of benzodiazepines in the four practices between 1989 and 1993. In 1990, 53.8% of benzodiazepine users received 3 or fewer prescriptions, 15.1% between 4 and 6 prescriptions, 14.4% between 7 and 10 prescriptions, 12.5% between 11 and 15 prescriptions, 1.9% between 16 and 20 prescriptions, and 2.3% were given 21 or more prescriptions. In addition, Table III shows the utilization of the anxiolytic benzodiazepines (as defined in Chapter 4.1.2 of the British National Formulary-) for the year 1990 and the utilization of all benzodiazepines in Tayside in 1993.

General hospital adm&sions During the general hospital study period there were 2628 subjects admitted, of which 2330 (88.7%) were not prescribed benzodiazepines at any time during the study period (see Table IV); 239 (9.1%) patients were taking benzodiazepines at the time of hospital admission and 194 (7.4%) continued to receive benzodiazepines after discharge, thus 45 (1.7%) discontinued community benzodiazepine prescribing following hospitalization. Examination of the hospital case records of those that discontinued revealed that 30 (1.1%) had their medication discontinued in the hospital, 9 (0.3%) did not receive a further community prescription after discharge but continued to receive their medication in the hospital until the time of discharge. The case records of six patients could not be found. Thirteen (0.5%) of the subjects who had their medication discontinued following hospitalization had received previous benzodiazepine prescriptions for longer than 4 weeks. Four (0.2%) had received their benzodiazepines for longer than 1 year. Fifty-nine (2.2%) subjects were begun on benzodiazepines following hospital admission. Examination of the case records revealed that 30 (1.1%) commenced benzodiazepines in the hospital and 20 (0.8%) were started in the community within 14 days of discharge. No information was available for nine admissions. Twenty-one (0.8%) patients subsequently continued to receive benzodiazepines for longer than 1 year. The diagnoses of those patients prescribed benzodiazepines after discharge from the hospital included medical diagnosis in 26, surgical diagnosis in 20, malignancy in 12, and alcohol intoxication in 1.

Psychiatric hospital admissions During the psychiatric hospital admission study period, 254 subjects (130 females) were admitted to a psychiatric hospital (see Table IV). Of these, 152 (59.8%) were not prescribed benzodiazepines at any time during the study period. Eightyfive (33.5%) patients were taking benzodiazepines at the time of admission and, of this group, 45 (17.7%) remained on this medication after discharge and 40 (15.7%) were discontinued. Examination of hospital records revealed that 32 (12.6%) pa-

Total

Lormetazepam Nitrazepam Temazepam Triazolam Chlordiazepoxide Diazepam 1,orazepam Oxazepam

Females

Males

Females

Psychiatric hospital study population 4/1/89-12/31/91

2 61 215 129 6 161 4 1

2118

11 230 748 589 15 493 22 1

5 188 450 377 21 391 15 1 5639

29 814 1671 1769 75 1190 84 7

2 81 349 237 12 262 5 1 4477

21 514 1548 1336 45 943 47 1

6 232 667 513 30 637 20 2

11,844

54 1784 3623 3549 162 2447 206 19

Subjects Prescriptions Subjects Prescriptions Subjects Prescriptions Subjects Prescriptions

Males

General hospital study population 4/1/90-12/31/90

Insomnia Insomnia Insomnia -Anxiety Anxiety/insomnia Anxiety/insomnia Anxiety

Indication

0.2 4.2 7.1 -0.8 4.1 1.7 0.5

No. of prescriptions (millions)

UK 1989

Table II.--The individual drugs prescribed in the general hospital and psychiatric hospital study populations. Note that, because subjects may receive more than one type of prescription, the subject totals do not add up to those given in Table I. Also shown are the indications and 1989 UK prescription totals (where available [9]) for these drugs.

r3~

"3

G

g

_=. ,7

e"

¢3 O

,g

1989 1990 1991 1992 1993 1993 all of Tayside 1990 anxiolytics

Number of subjects in year

8583 9907 9924 9151 8528

148,513

2353

26,116

640

Total prescriptions

1738 1865 1729 1652 1628

Total subjects

315

8764

614 650 576 610 594

1

91

2618

215 222 180 167 170

2

40

1683

131 132 108 96 114

3

26

1393

111 103 97 86 90

4

26

1302

103 98 83 63 66

5

19

1660

92 80 95 78 75

6

22

1281

68 90 82 80 69

7

18

930

69 72 80 58 56

8

11

810

39 56 63 47 60

9

11

774

44 51 48 50 54

10

51

3596

197 234 224 246 219

11-15

3

644

29 35 49 38 32

16-20

Number of subjects receiving the number of prescriptions in 1 year

7

661

26 42 44 33 29

21+

Table III.--AII benzodiazepine prescribing shown as the number of patients and the number of prescriptions received in the years 1989 to 1993. Also shown are anxiolytics (chlordiazepoxide, clobazam, diazepam, lorazepam, oxazepam) for 1990 and all prescribing for all benzodiazepines for the whole of the Tayside region for 1993 (population 383,848) [15].

7~

t>

Hospitalization and communitybenzodiazepine prescribing

67

Table IV.--Subjects admitted to general and psychiatric hospitals and their community benzodiazepine prescribing prior to and following hospitalization. General hospital

Group 1: No benzodiazepines Group 2: Benzodiazepines both before and after admission Group 3: Benzodiazepines before admission only Group 4: Benzodiazepines after discharge only Total

Psychiatric hospital

Males

Females

Total

Males

Females

Total

1168

1162

2330

77

75

152

58

136

194

19

26

45

16

29

45

19

21

40

19 1261

40 1367

59 2628

9 124

8 130

17 254

tients had their medication discontinued in the hospital, 4 (1.6%) continued to receive their medication in the hospital but did not have it continued by their general practitioner in the community, and case records could not be found for 4 patients. Seventeen (6.7%) subjects were not taking benzodiazepines prior to admission but commenced benzodiazepines during hospital admission. All these prescriptions were continued in the community for longer than 4 weeks. The diagnoses of the 17 patients started on benzodiazepines during admission were depression (n =8), senile dementia (n=3), alcohol problems (n=2), paranoid psychosis ( n = l ) , severe mental handicap (n = 1), anxiety (n = 1), and brain damage (n--1). The most frequent diagnosis was thus depression, with only one patient suffering from anxiety. Overall, the number of patients receiving benzOdiazepines fell from 33% on admission to 24% on discharge. In the log-linear analyses, females were more likely to be prescribed benzodiazepines after discharge from either type of hospital (chi-square = 29.85, p<0.001). There was also a significant association between type of hospital benzodiazepine status before hospitalization and benzodiazepine status after hospitalization (chisquare = 50.85, p<0.001). When compared to a psychiatric hospital, subjects admitted to a general hospital were less likely to commence benzodiazepines (odds ratio 0.23; 95% CI 0.14-0.38), but were also less likely to discontinue benzodiazepines (odds ratio 0.20; 95% CI 0.15-0.26). Of these subjects receiving benzodiazepines at any time, a higher proportion received them both before and after hospitalization in the general hospital group (odds ratio 3.83; 95% CI 2.28-6.44). However, a much smaller proportion of the total number of subjects in the general hospital group received benzodiazepines at any time (11.3% of general hospital subjects versus 40.2% of psychiatric hospital subjects). DISCUSSION The principle findings of the present study are that general hospital admission has a minor effect on total benzodiazepine prescribing with only 59 of a population of 2628 subjects admitted to a general hospital commencing treatment, 21 of which continued treatment for more than 1 year. Balancing this small increase, 45 subjects discontinued benzodiazepine treatment and, of these, 4 had previously been treated

68

H.L. MILLAR et

aL

for more than 1 year and 13 for more than 1 month. Thus, admission to a general hospital increased the percentage of admitted subjects receiving benzodiazepine prescriptions by 0.65%. When this is viewed in the light of the 1865 subjects receiving benzodiazepines in the study population, this increase is triVial. Admission to a psychiatric hospital had a more marked effect mainly because a much higher proportion of admissions (40%) received benzodiazepine at any time. Seventeen subjects of the 254 admitted commenced benzodiazepine treatment and all continued these for more that 4 weeks. This was balanced by 40 subjects discontinuing these drugs. The net effect of a psychiatric hospitalization was a reduction in benzodiazepine use by 9% in those hospitalized. Once again, however, this effect is small when compared to the total burden of benzodiazepine prescribing in the population. The results of the present study puts into perspective the previously published work in this area. Surendrakumar and colleagues [4] examined discharge prescriptions in one hospital over a 2-week period and excluded psychiatric cases. They concluded that the 17 new users of benzodiazepines they found represented an unacceptable increase in prescription rate. Although we found a small net increase in prescribing of these drugs, a significant proportion were given to patients with newly diagnosed malignancy in whom anxiety and insomnia may understandably be a problem. In addition, 20 of 59 had their benzodiazepine treatment initiated after hospital discharge. In our view, the impact on benzodiazepine prescribing of admission to a general hospital is minimal. Psychiatric hospital admission has not previously been studied. We have found that psychiatric hospitalization reduces community benzodiazepine prescribing from high baseline but, perhaps not surprisingly, patients discharged from a psychiatric hospital are much more likely to receive community benzodiazepine prescribing than patients admitted to a general hospital. Wright et al. [8] found a point prevalence of 65 subjects taking long-term daytime benzodiazepines among their practice population of 13,000 patients. They did not define long-term drug use, but if we take greater than six prescriptions per year as a reasonable definition of longterm use, then we find 123 axiolytic benzodiazepine users in the present study population (from Table III), which is approximately twice the size of theirs. Therefore, it would appear that our study population is not dramatically different from theirs. Our data also agree very well with those of van der Waals et al. [1] who found that 4231 of 61,249 subjects (6.9%) received one or more benzodiazepine prescriptions, and that one third were given long-term treatment. We found that 26,116 subjects (see Table 3) of the approximately 383,848 [9] in Tayside (6.8%) received one or more prescriptions for a benzodiazepine and that long-term users (greater than six prescriptions per year) accounted for 33.3% (calculated from Table III). Our study has a number of weaknesses. We did not know the prescribing indication in the community. We did not differentiate community prescribing initiated by general practitioners and that prescribed on the advice of a hospital out-patient consultation. Our data are also somewhat historical and practice may have changed more recently. In addition a proportion of the hospital case records could not be accessed. Against these weaknesses are the strengths of a population-based approach which allowed the overall effect of hospitalization to be put into the context of the total burden of prescribing. We also know that the prescriptions were dispensed and thus primary noncompliance was eliminated [10].

Hospitalization and community benzodiazepine prescribing

69

In addition, because our data were person-specific, linkage of community prescribing with hospitalization was complete, thus eliminating any possible sampling errors. It is clear that long-term prescribing of benzodiazepines in the community has a high prevalence. Such prescribing carries a significant rate of morbidity [11]. Benzodiazepines tend to be given to patients with more comorbidities, who have more instances of coprescribing, and who consequently have more consultations [12]. Benzodiazepine overprescribing is recognized by general practitioners as a problem [13] and strategies to reduce this have been proposed [14]. Hospitalization has previously been cited as one possible cause for such over prescribing [4]. The results of the present study suggest that the effects of hospitalization are likely to be very minimal. Acknowledgments--MEMO is supported by the Medicines Control Agency.

REFERENCES 1. van der Waals FW, Mohrs J, Foets M. Sex differences among recipients of benzodiazepines in Dutch general practice. BMJ 1993;307:363-366. 2. Catalan J, Gath DH. Benzodiazepines in general practice: time for a decision. BMJ 1985:290: 1374-1376. 3. Shan K, Nolan JA, Turner P, Jackson SHD. Prescription of benzodiazepines in a London teaching hospital. J R Soc Med 1990;83:366-367. 4. Surendrakumar D, Dunn M, Roberts CJC. Hospital admission and the start of benzodiazepinc use. BMJ 1993:304:881. 5. Edwards C, Bushnell JL, Ashton CH, Rawlins MD. Hospital prescribing and usage of hypnotics and anxiolytics. Br J Clin Pharmacol 1991:31:190-192. 6. Brayley J, Rafalowicz E, Yellowlees P. Psychotropic drug prescribing in a general hospital inpatient psychiatric unit. Austral NZ J Psychiatry 1989;23:352-356. 7. MacDonald TM, McDevitt DG. The Tayside Medicines Monitoring Unit (MEMO) In: Strom BL. ed. Pharmacoepidemiology, 2nd ed. Chichester, UK: John Wiley & Sons L994:245-255. 8. Wright N, Chapter R, Payne S. Community survey of long term daytime use of benzodiazepincs. BMJ 1994;309:27-28. 9. General Registrar Office for Scotland 1991. Census report for Fayside region: 1. Edinburgh: HMSO 1993. 10. Beardon PHG, McGilchrist MM, McKendrick AD, McDevitt DG, MacDonald TM. Primary noncompliance with prescribed medication in primary care. BMJ 1993:307:846-848. 1 I. Ray WA, Griffin MR, Downey W. Benzodiazepines of long and short elimination half-life and the risk of hip fracture. JAMA 1989;262:303-307. 12. Simpson RJ, Power KG, Wallace LA, Butcher MH, Swanson V, Simpson EC. Controlled comparison of the characteristics of long-term benzodiazepinc users in general practice. Br J Gen Pract 1990;40:22-26. 13. Hamilton IJD, Reay LM, Sullivan FM. A survey of general practitioners attitudes to benzodiazepinc overprescribing. Health Bull (Edinburgh) 1990;46:299-303. 14. Tiller JWG. Reducing the use of benzodiazepines in general practice. BMJ 1994;309:3~J, 15. The Mental Health Foundation guidelines for the prevention of treatment of benzodiazepine dependence. Lader M, Russell J, eds. London: The Mental Health Foundation 1993.