EVALUATION OF COMPUTER SUPPORT FOR PRESCRIBING (CAPSULE) USING SIMULATED CASES

Objective: To evaluate the potential effect of computer support on gen eral practitioners prescribing, and to compare the effectiveness of th ree different support levels. Design: Crossover experiment with balanc ed block design. Subjects: Random sample of 50 general practitioners ( 42 agreed to participate) from 165 in a geographically defined area of Oxfordshire. Interventions: Doctors prescribed for 36 simulated cases constructed from real consultations. Levels of computer support were control (alphabetical list of drugs), limited support (list of preferr ed drugs), and full support (the same list with explanations available for suggestions). Main outcome measures: Percentage of cases where do ctors ignored a cheaper, equally effective drug; prescribing score (a measure of how closely prescriptions matched expert recommendations); interview to elicit doctors' views of support system. Results: Compute r support significantly improved the quality of prescribing. Doctors i gnored a cheaper, equally effective drug in a median 50% (range 25%-75 %) of control cases, compared with 36% (8%-67%) with limited support a nd 35% (0-67%) with full support (P<0.001). The median prescribing sco re rose from 6.0 units (4.2-7.0) with control support to 6.8 (5.8 to 7 .7) and 6.7 (5.6 to 7.8) with limited and full support (P<0.001). Of 4 1 doctors, 36 (88%) found the system easy to use and 24 (59%) said the y would be likely to use it in practice.Conclusions: Computer support improved compliance with prescribing guidelines, reducing the occasion s when doctors ignored a cheaper, equally effective drug. The system w as easy to operate, and most participating doctors would be likely to use it in practice.