Outpatient antibiotic prescriptions from 1992 to 2001 in The Netherlands

Marijke M. Kuyvenhoven*, Frank A. M. van Balen and Theo J. M. Verheij

Julius Center for Health Sciences and Primary Care, University Medical Center (UMC) Utrecht, PO Box 85060, 3508 AB Utrecht, The Netherlands

Received 17 March 2003; returned 2 June 2003; revised 27 June 2003; accepted 12 July 2003


    Abstract
 Top
 Abstract
 Introduction
 Materials and methods
 Results
 Discussion
 References
 
Objectives: Although Dutch outpatient antibiotic prescription rates are low compared with other European countries, continuing to scrutinize trends in outpatient antibiotic use is important in order to identify possible increases in antibiotic use or inappropriate increases in the use of particular classes of antibiotics.

Methods: We assessed the volume of Dutch outpatient antibiotic prescriptions from 1992 to 2001 by calculating the mean number of outpatient antibiotic prescriptions (indicating the number of times physicians decide to prescribe an antibiotic agent) per 1000 patients insured by the Dutch Sickness Fund per year, according to subgroups (narrow-spectrum penicillins, broad-spectrum penicillins, tetracyclines, macrolides, sulphonamides and trimethoprim, and quinolones). Data were obtained from the Dutch Drug Information Project/Health Care Insurance Board.

Results: The total volume of outpatient antibiotic prescriptions in 2001 was 394 prescriptions per 1000 patients insured by the Dutch Sickness Fund. Overall, the rates were stable between 1992 and 2001, with small variations across years, but with marked differences in volumes within antibiotic groups across these years: a decrease in prescribing of narrow-spectrum penicillins (–29%), amoxicillin (–23%), tetracycline (–24%), doxycycline (–19%) and trimethoprim and derivatives (–45%) was accompanied by an increase in prescribing of co-amoxiclav (+85%), macrolides (+110%) and quinolones (+86%).

Conclusions: The international trend of a decline in the use of narrow-spectrum and older penicillins and prescribing more broad-spectrum and new chemotherapeutics was shown to exist in a low prescribing country, The Netherlands. Therefore, inappropriate antibiotic prescribing should remain prominent on the research agenda in intervention studies in order to improve the appropriate selection of antibiotic class and to reduce the prescription of antibiotics.

Keywords: antibiotic prescription, broader-spectrum antibiotics, newer antibiotics, general practice, The Netherlands


    Introduction
 Top
 Abstract
 Introduction
 Materials and methods
 Results
 Discussion
 References
 
About 80% of antibiotic prescriptions for systemic use are prescribed in primary care. Respiratory tract infections are the most common indication. There is only limited evidence that antibiotics shorten the duration of symptoms in cases of common colds, acute otitis media, sore throat/tonsillitis, sinusitis and bronchitis.14 Recently, the rate of antibiotic prescribing has been decreasing in Britain5,6 and the USA.7,8 Although the Dutch antibiotic prescibing rates are low compared with other European countries and the USA,9 even in The Netherlands up to 50% of antibiotic prescriptions in respiratory cases are probably unnecessary.10 Over-prescribing unnecessarily exposes patients to risk of side effects, encourages re-consulting for similar problems and enhances antimicrobial resistance. Continuing to scrutinize trends in outpatient antibiotic use is important in order to identify possible inappropriate increases in the use of particular classes of antibiotics.6,8,11 Therefore, in this study we examined the volume of outpatient antibiotic prescriptions from 1992 to 2001 in The Netherlands.


    Materials and methods
 Top
 Abstract
 Introduction
 Materials and methods
 Results
 Discussion
 References
 
The volume of outpatient antibiotic prescriptions was estimated by calculating the mean number of outpatient antibiotic prescriptions (indicating the amount of times physicians decide to prescribe an antibiotic agent) per 1000 patients insured by the Dutch Sickness Fund per year (source: Dutch Drug Information Project/Health Care Insurance Board) according to the following groups: (i) narrow-spectrum penicillins (J01CE); (ii) broad-spectrum penicillins (J01CA/R); (iii) tetracyclines (J01AA); (iv) macrolides (J01FA); (v) sulphonamides and trimethoprim (J01E); and (vi) quinolones (J01MA). Flucloxacillin (J01CF) and cephalosporins (J01D) were excluded, because these antibiotics are hardly ever prescribed in Dutch outpatient care.1 The data are for 2 000 000 patients in 1992 and 5 550 000 patients in 2001, due to a growing number of participating regions. Two-thirds of the Dutch population are covered for their medical care by the Dutch Sickness Fund, with a maximum wage level for entitlement. This means that these patients have a lower level of education and are somewhat older compared with privately insured patients.


    Results
 Top
 Abstract
 Introduction
 Materials and methods
 Results
 Discussion
 References
 
About 85% of prescriptions in all the above groups of antibiotics were prescribed by general practitioners (GPs) and ~15% by medical specialists. The total volume of outpatient antibiotic prescriptions in 2001 was 394 prescriptions per 1000 Dutch Sickness Fund patients, which is equivalent to 3397 defined daily doses (DDD) per 1000 patients per year and 9.3 DDD per 1000 patients per day. The total volume was rather stable between 1992 and 2001, with small variations across years (see Table 1), but with marked differences in prescribed volumes within antibiotic groups across these years. There was a steady decrease in the number of prescriptions of narrow-spectrum penicillins, tetracyclines (doxycycline, –19%; tetracycline, –24%), and sulphonamides and trimethoprim (especially trimethoprim and derivatives, –45%). The volume of broad-spectrum penicillins was about the same across the years, with a decrease in the use of amoxicillin (–23%) and an increase in the use of co-amoxiclav (+85%). The volume of macrolides (especially clarithromycin and since 1994 azithromycin) and quinolones doubled across these years. In 1992, one out of every 10 prescriptions (12%) related to macrolides or quinolones, while in 2001 nearly one out of every four (23%) did. Further inspection of the data using subgroup analyses showed that these trends were a result of prescriptions by GPs as well as prescriptions by medical specialists.


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Table 1. Outpatient antibiotic use in The Netherlands in 1992–2001
 

    Discussion
 Top
 Abstract
 Introduction
 Materials and methods
 Results
 Discussion
 References
 
The data used in this study concerned ~30% of the Dutch population in 2001, and are assumed to give a reliable indication of the total amount of prescriptions in Dutch outpatient care for Dutch Sickness Fund patients.2 Overall, the Dutch outpatient antibiotic prescription rates have been rather stable since the early 1990s. They have not declined as in the UK and USA.58 Because of yearly variations, we think it is sensible to use figures relating to periods of several years when monitoring of national figures, to prevent invalid conclusions owing to random yearly variation.

The decrease in the use of narrow-spectrum penicillins and the increasing use of co-amoxiclav, macrolides and quinolones indicates that the international trend of declining use of narrower spectrum and older penicillins and of prescribing more broad-spectrum and new chemotherapeutics8,11 is also present in a low prescribing country, i.e. The Netherlands, among GPs as well as medical specialists. The increase in the prescription of co-amoxiclav, macrolides and quinolones is noteworthy, because these drugs are seldomly first-choice treatments in Dutch national guidelines for respiratory and urinary tract cases in primary care, and the resistance patterns in The Netherlands do not justify their use as a first choice of drug.

The reasons for these trends are unknown. However, recently, pharmaceutical marketing activities in The Netherlands relating to 11 therapeutic markets have been shown to make doctors less sensitive to costs and quality in prescribing drugs, and to reduce the choice of competing drugs.12 This finding might explain the increase of newer (i.e. broader spectrum) antibiotics, like macrolides, to the detriment of older (i.e. narrower spectrum) antibiotics. Such a trend is unwanted, because growing use of newer and broader spectrum drugs like macrolides has been accompanied by growing resistance of important pathogens like Streptococcus pneumoniae and Helicobacter pylori to macrolides in The Netherlands.13,14

More emphasis on implementation of guidelines aimed at prescribing narrower spectrum and older penicillins in respiratory tract infections and especially lower respiratory tract infections seems to be needed, in addition to developing and implementing specific consultation strategies to promote more appropriate use of antibiotics in primary care.15 Inappropriate antibiotic prescribing should therefore remain prominent on the research agenda, aiming at intervention studies to improve the appropriate selection of antibiotic class and to reduce the prescription of antibiotics, as well as studies to identify patients at greater risk of complications or a long-lasting disease course.16,17


    Acknowledgements
 
We thank Ilias de Graaf (medical student) for statistical analysis. We are grateful to the Dutch Drug Information Project/Health Care Insurance Board for supplying the data. None of us had any conflicting interests.


    Footnotes
 
* Corresponding author. Tel: +31-30-253-8198; Fax: +31-30-253-9028; E-mail: m.m.kuyvenhoven{at}med.uu.nl Back


    References
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 Abstract
 Introduction
 Materials and methods
 Results
 Discussion
 References
 
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13 . Debets-Ossenkopp, Y. J., Herscheid, A. J., Pot, R. G. J. et al. (1999). Prevalence of Helicobacter pylori resistance to metronidazole, clarithromycin, amoxycillin, tetracycline and trovafloxacin in The Netherlands. Journal of Antimicrobial Chemotherapy 43, 511–5.[Abstract/Free Full Text]

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16 . Coenen, S., Kuyenhoven, M. M., Butler, C. C. et al. (2001). Variation in European antibiotic use. Lancet 358, 1272.

17 . De Meyere, M., Guillemot, D. & Verheij, T. (2001). Interventions in the community related to antibiotic use. In Final Report of the European Conference on Antibiotic Use in Europe, November 15–17, pp. 38–43. European Surveillance of Antimicrobal Consumption (ESAC), Brussels, Belgium.