Use of the statins in patients after acute myocardial infarction: does evidence change practice?

Abstract

To compare the use of lipid-lowering agents in 42 628 elderly patients (aged > or =65 years) after acute myocardial infarction, before and after the publication of the Scandinavian Simvastatin Survival Study (4S), using the Ontario Myocardial Infarction Database. Multivariate regression models were created to estimate changes in the rate of statin use over time in monthly cohorts of elderly patients after acute myocardial infarction in Ontario from April 1, 1992, to March 31, 1997. Changes in the rate of statin use over time were estimated using patient and prescriber characteristics. We found a 3.6-fold significant increase in the monthly rate of statin use after the publication of 4S compared with before the publication of 4S (P<.001); specifically, the rate of increase in simvastatin and pravastatin sodium use was higher after the publication of 4S (P<.001 for each). Before the publication of 4S, the rate of increase in statin use in younger patients (aged 65-74 years) was 2.7 times higher than in older patients (aged > or =75 years) (P =.02), while after the publication of 4S, the rate of increase in statin use was only 1.8-fold higher in the younger group (P<.001). After the publication of 4S, there was a 1.6-fold higher rate of increase in statin use in male compared with female patients (P =.006). Also after the publication of 4S, specialists (cardiologists and internists) had a 2-fold higher rate of increased use of the statins than did generalists (P<.001). It is possible to shift practice if the evidence of benefit is strong, the intervention is easy to implement, and the intervention is marketed aggressively.