Hydroxymethylglutaryl-CoA reductase inhibitors in older persons with acute myocardial infarction: Evidence for an age-statin interaction

OBJECTIVES: To characterize the relationship between hydroxymethylglutaryl-CoA reductase inhibitors (statins) and outcomes in older persons with acute myocardial infarction (AMI). DESIGN: Observational study. SETTING: Acute care hospitals in the United States from April 1998 to June 2001. PARTICIPANTS: Medicare patients aged 65 and older with a principal discharge diagnosis of AMI (N = 65,020) who did and did not receive a discharge prescription for statins. MEASUREMENTS: The primary outcome of interest was all-cause mortality at 3 years after discharge. RESULTS: Of 23,013 patients with AMI assessed, 5,513 (24.0%) were receiving a statin at discharge. Nearly 40% of eligible patients (n=8,452) were aged 80 and older, of whom 1,310 (15.5%) were receiving a statin at discharge. In a multivariable model taking into account demographic, clinical, physician and hospital characteristics, and propensity score, discharge statin therapy was associated with significantly lower 3-year mortality (hazard ratio (HR) = 0.89 (95% confidence interval (CI) = 0.83-0.96)). In an analysis stratified by age, discharge statins were associated with lower mortality in patients younger than 80 (HR = 0.84, 95% CI = 0.76-0.92) but not in those aged 80 and older (HR= 0.97, 95% CI = 0.87-1.09). CONCLUSION: Statin therapy is associated with lower mortality in older patients with AMI younger than 80 but not in those aged 80 and older, as a group. This finding questions whether statin efficacy data in younger patients can be broadly applied to the very old and indicates the need for further study of this group.