Background: Many guidelines are not developed from systematic models and are not based on high-quality evidence. The existence of a guideline does not in itself lead to changes in practice and many guidelines are not used once they have been issued.
Material and methods: A questionnaire on continuing education and the use of guidelines was sent to 1500 general practitioners (GP) and GP assistants in 1321 general practices in Norway. 857 GPs and 948 GP assistants returned the questionnaire.
Results: There was a large variation in the extent to which guidelines were known and used. Many GPs and GP assistants had little knowledge of guidelines published in the Journal of the Norwegian Medical Association or by the Norwegian Medicines Agency, the Norwegian Board of Health or the Norwegian Centre for Health Technology Assessment. There were exceptions: 52% of GPs used the Norwegian College of General Practitioners' treatment programme for diabetes and 77% of GP assistants used the Norwegian quality assurance programme for laboratory services in primary care.
Interpretation: Guidelines should be based on the best available evidence but this in itself is not enough to ensure that they are adhered to. Effective strategies for implementation are also important.