OBJECTIVE: To analyse the effect of guidelines accompanied by changes in reimbursement rules for the prescription of lipid-lowering drugs (LLDs).

DESIGN: Observational study focusing on LLD use before (1994-98) and after an intervention (1999).

SETTING: Guidelines were developed by the Danish College of General Practitioners and focused on prevention of cardiovascular heart disease (CHD). Guidelines were sent out and changes in reimbursement took place in December 1998. Prescriptions for LLDs were extracted from a population-based prescription database (Odense University Pharmacoepidemiological Database, OPED) covering 10% of the Danish population (470,000 inhabitants).

MAIN OUTCOME MEASURES: Incidence rate and 1 year prevalence rate (annual prevalence) of LLD use.

RESULTS: The incidence of LLD use increased significantly in the year following the intervention. Incidence rate ratio (after/before) was 1.43 (CI 1.35-1.52). The annual prevalence of LLD use in the population increased by 0.4% after the intervention (0.2% before). The corresponding figure for patients with diabetes mellitus (treated with insulin or oral anti-diabetics) was 2.3% after the intervention (1.2% before), and for patients with CHD (treated with vasodilators) 8.1% after the intervention (5.0% before).

CONCLUSION: Guidelines accompanied by a change in reimbursement rules had a significant influence on the prescribing of lipid-lowering drugs.