title: Do decision support systems influence variation in prescription?
abstract: BACKGROUND
  Translating scientific evidence into daily practice is problematic. All kinds of intervention strategies, using educational and/or directive strategies, aimed at modifying behavior, have evolved, but have been found only partially successful. In this article the focus is on (computerized) decision support systems (DSSs). DSSs intervene in physicians' daily routine, as opposed to interventions that aim at influencing knowledge in order to change behavior. We examined whether general practitioners (GPs) are prescribing in accordance with the advice given by the DSS and whether there is less variation in prescription when the DSS is used.
  
  
  METHODS
  Data were used from the Second Dutch National Survey of General Practice (DNSGP2), collected in 2001. A total of 82 diagnoses, 749811 contacts, 133 physicians, and 85 practices was included in the analyses. GPs using the DSS daily were compared to GPs who do not use the DSS. Multilevel analyses were used to analyse the data. Two outcome measures were chosen: whether prescription was in accordance with the advice of the DSS or not, and a measure of concentration, the Herfindahl-Hirschman Index (HHI).
  
  
  RESULTS
  GPs who use the DSS daily prescribe more according to the advice given in the DSS than GPs who do not use the DSS. Contradictory to our expectation there was no significant difference between the HHIs for both groups: variation in prescription was comparable.
  
  
  CONCLUSIONS
  We studied the use of a DSS for drug prescribing in general practice in the Netherlands. The DSS is based on guidelines developed by the Dutch College of General Practitioners and implemented in the Electronic Medical Systems of the GPs. GPs using the DSS more often prescribe in accordance with the advice given in the DSS compared to GPs not using the DSS. This finding, however, did not mean that variation is lower; variation is the same for GPs using and for GPs not using a DSS. Implications of the study are that DSSs can be used to implement guidelines, but that it should not be expected that variation is limited.
authors.affiliation: NIVEL-Netherlands Institute for Health Services Research, PO Box 1568, 3500 BN Utrecht, the Netherlands. j.dejong@nivel.nl
authors.forename: Judith D
authors.initials: JD
authors.lastname: de Jong
authors.forename: Peter P
authors.initials: PP
authors.lastname: Groenewegen
authors.forename: Peter
authors.initials: P
authors.lastname: Spreeuwenberg
authors.forename: Gert P
authors.initials: GP
authors.lastname: Westert
authors.forename: Dinny H
authors.initials: DH
authors.lastname: de Bakker
mesh_terms: D000328:Adult; D000368:Aged; D020000:Decision Support Systems, Clinical / Q000706:statistics & numerical data*; D011307:Drug Prescriptions / Q000706:statistics & numerical data; D004360:Drug Therapy, Computer-Assisted; D017723:Drug Utilization Review; D005194:Family Practice / Q000706:statistics & numerical data; D005260:Female; D019983:Guideline Adherence; D006801:Humans; D008297:Male; D008875:Middle Aged; D055361:Multilevel Analysis; D009426:Netherlands; D010818:Practice Patterns, Physicians' / Q000592:standards* / Q000706:statistics & numerical data; D011785:Quality Assurance, Health Care; D011795:Surveys and Questionnaires