Different Patterns of Statin Use in Patients with Acute Myocardial Infarction

Abstract

Statins have well-established cardiovascular benefits, and recent evidence suggests that discontinuing statin therapy after acute myocardial infarction (AMI) is harmful. Our objective was to assess the association between statin discontinuation post-AMI and 1-year all-cause mortality in a real world setting. Data on survivors of AMI between 2000 and 2007 were extracted from the hospital discharge summary database of Quebec and the provincial physician and drug claims database. Statin prescription filling was used to establish cohort groups. Previous statin use was defined as having filled a statin prescription in the 90 days pre-AMI, while post-AMI statin use was filling a prescription between discharge from hospital post-AMI and 90 days post-discharge. AMI patients who survived 90 days (n=48,229) were divided into 4 groups: i) non-users (n=11,657), did not receive statins pre- or post- AMI (reference group), ii) starters (n=22,452), received statins only post-AMI, iii) stoppers (n=488), received statins pre- but not post-AMI, and, iv) users (n=13,632), received statins pre- and post-AMI. Cox proportional hazards models were used to calculate hazard ratios (HR). Compared with non-users, stoppers had increased 1-year all-cause mortality (adjusted HR 1.36; 95% CI 1.08- 1.70, P=0.008). Starters (HR 0.65; 95% CI 0.59-0.71, P<0.0001) and users (HR 0.81; 95% CI 0.74-0.88, P<0.0001) had lower mortality than non-users. Discontinuation of statins in survivors of AMI was associated with an increase in 1-year all-cause mortality. Physicians should use caution when discontinuing statins post-AMI.