title: Determinants of the range of drugs prescribed in general practice: a cross-sectional analysis.
abstract: BACKGROUND
  Current health policies assume that prescribing is more efficient and rational when general practitioners (GPs) work with a formulary or restricted drugs lists and thus with a limited range of drugs. Therefore we studied determinants of the range of drugs prescribed by general practitioners, distinguishing general GP-characteristics, characteristics of the practice setting, characteristics of the patient population and information sources used by GPs.
  
  
  METHODS
  Secondary analysis was carried out on data from the Second Dutch Survey in General Practice. Data were available for 138 GPs working in 93 practices. ATC-coded prescription data from electronic medical records, census data and data from GP/practice questionnaires were analyzed with multilevel techniques.
  
  
  RESULTS
  The average GP writes prescriptions for 233 different drugs, i.e. 30% of the available drugs on the market within one year. There is considerable variation between ATC main groups and subgroups and between GPs. GPs with larger patient lists, GPs with higher prescribing volumes and GPs who frequently receive representatives from the pharmaceutical industry have a broader range when controlled for other variables.
  
  
  CONCLUSIONS
  The range of drugs prescribed is a useful instrument for analysing GPs' prescribing behaviour. It shows both variation between GPs and between therapeutic groups. Statistically significant relationships found were in line with the hypotheses formulated, like the one concerning the influence of the industry. Further research should be done into the relationship between the range and quality of prescribing and the reasons why some GPs prescribe a greater number of different drugs than others.
authors: NIVEL Netherlands institute for health services research, PO Box 1568, Utrecht, The Netherlands. d.debakker@nivel.nl
authors: Dinny H
authors: DH
authors: de Bakker
authors: Dayline S V
authors: DS
authors: Coffie
authors: Eibert R
authors: ER
authors: Heerdink
authors: Liset
authors: L
authors: van Dijk
authors: Peter P
authors: PP
authors: Groenewegen
mesh_terms: D001291:Attitude of Health Personnel; D003430:Cross-Sectional Studies; D004345:Drug Industry; D011307:Drug Prescriptions; D017723:Drug Utilization Review; D005194:Family Practice / Q000458:organization & administration*; D005260:Female; D005569:Formularies as Topic; D019538:Health Care Surveys; D006291:Health Policy; D006801:Humans; D008297:Male; D016347:Medical Records Systems, Computerized; D009426:Netherlands; D010818:Practice Patterns, Physicians'; D011795:Surveys and Questionnaires
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