Impact of local evidence-based clinical guidelines--a Danish intervention study

We aimed to evaluate whether a cheap and less labour-intensive regional implementation strategy for guidelines was sufficient to change knowledge and behaviour among GPs. The model studied was the implementation of anticoagulant therapy to prevent stroke in atrial fibrillation.

The intervention took place in the county of Viborg (149 GPs), Denmark, with the county of Ringkøbing (166 GPs) as control. A local interdisciplinary steering group modified national college-based guidelines, followed by a regional dissemination and implementation strategy. The effect of the intervention was evaluated during a follow-up period by a repeated questionnaire and by monitoring prescriptions for oral anticoagulants in 1993 and 1995 in the Danish National Health Service.

Adherence to the guidelines was higher after the intervention but, considering secular trends and baseline differences, the guidelines had no significant effect. The use of oral anticoagulants increased substantially in both counties during the 2-year follow-up period, but the difference in relative change between the counties was negligible. Adherence to the guidelines could not be predicted by any of the reported practice characteristics or attitudes to guidelines.

Despite solid scientific documentation and regional modification to establish ownership of nationally agreed guidelines, the impact of guidelines on GPs' knowledge and behaviour was disappointing.