Association Between Time of Statin Initiation After Hospital Discharge from Acute Myocardial Infarction and Risk of Recurrence and Mortality in Patients ≥65 Years of Age

Abstract

Clinical studies have shown the benefit of statin use after acute myocardial infarction (AMI). However, it is uncertain how this benefit relates to the timing of statin initiation after AMI. We created a retrospective cohort (from 1996 to 2001) using health care databases in Quebec, Canada, to study patients (> or =65 years of age) who had AMI and differed in time of statin initiation within the first 90 days after discharge. Rates of recurrent AMI and mortality were compared between patients who initiated statins at discharge (early group) and those who initiated statins 1 month later and up to 90 days after discharge (delayed group). A multivariate Cox's regression model was used in the comparison. We used prescription time distribution matching to control for survival difference between groups. The early and delayed groups consisted of 3,075 and 1,187 patients, respectively. During the 1-year follow-up, there was no evidence to suggest a difference in outcome between groups. Adjusted hazard ratios for early versus delayed initiation were 1.03 (95% confidence interval 0.56 to 1.87) at 3 months and 1.24 (95% confidence interval 0.96 to 1.62) at 1 year. Analyses that were restricted to first-time statin users or excluded patients who had severe co-morbidity or were > or =85 years old did not change the results. Our findings were not affected by changing the definition of delayed use within the 90-day period. In conclusion, delay of statin initiation up to 30 to 90 days after discharge after AMI does not appear to lead to a difference in the rates of recurrent AMI and mortality compared with statin initiation at discharge.