The influence of guidelines on the use of statins: analysis of prescribing trends 1998-2002

Aims: To monitor statin prescribing trends over time in order to determine whether prescribers were influenced by study results and/or clinical guidelines in terms of type and dosage of statin prescribed. Methods The GMS (General Medical Services) prescription database in Ireland was used to identify a cohort of patients, prescribed statins, in order to investigate prescribing trends from January 1998-December 2002. Statin prescribing rates for patients with ischaemic heart disease and diabetes were compared with rates in the general GMS population. Logistic regression analysis was used in patients with ischaemic heart disease and diabetes and adjusted odds ratios and 95% confidence intervals presented. Results Increased statin prescribing over time was noted (test for linear trend P < 0.0001). Pravastatin was the most frequently prescribed, followed by atorvastatin; simvastatin and fluvastatin showed lower rates of prescribing. Atorvastatin showed the greatest increased rate over time. An increase in the overall dose prescribed (test for trend P < 0.01) was chiefly due to increases in pravastatin dose, but doses were still below those recommended from clinical trials. Statins were prescribed more frequently in patients with ischaemic heart disease and diabetes, 44% (95% CI 43-45%) compared with the total GMS population, 7.7% (95% CI 7.6-7.8%), by December 2002. However, statins were only prescribed to 52% (95% CI 51-53%) of ischaemic heart disease patients and 40% (95% CI 39-41%) of patients with diabetes by December 2002. Patients aged 45-64 years were more likely to receive statins, compared with those aged 65 years and older. Conclusion: These findings suggest that the beneficial effects of statins shown in clinical studies may not be achieved in practice.