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

Abstract

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.

Figure 1

Unadjusted Kaplan-Meier estimates of 3-year survival in patients prescribed statins at discharge versus patients not prescribed statins at discharge.

Figure 2

Adjusted hazard ratio (HR) of 3-year mortality for patients prescribed statins at discharges versus patients not prescribed statins at discharge by 5-year age increments. HR >1 indicates excess risk of death for statin prescription compared with no statin prescription; HR<1 indicates lesser risk of death.

Figure 3

Adjusted odds of 3-year mortality for patients prescribed statins at discharge versus patients not prescribed statins at discharge by age 80 and older. Odds ratio>1 indicates excess risk of death for statin prescription compared with no statin prescription; odds ratio<1 indicates lesser risk of death.