Age-dependent associations of high-intensity statin therapy with 3-year clinical outcomes after acute myocardial infarction: longitudinal LDL-C profiles in a nationwide registry

High-intensity statin therapy is an important strategy for secondary prevention after acute myocardial infarction (AMI), but its clinical benefit in very elderly patients remains uncertain. We aimed to evaluate whether the association of high-intensity statins with clinical outcomes differs by age in older AMI patients undergoing percutaneous coronary intervention (PCI).

Using the Korean Acute Myocardial Infarction Registry–National Institutes of Health (KAMIR-NIH), we compared outcomes of high-intensity versus non–high-intensity statins among 4,147 patients aged ≥ 65 years treated with PCI and discharged on statins, stratified by age (65–74 years, n = 2,316; ≥75 years, n = 1,831), in overall and propensity score–matched cohorts (matched on age, sex, body mass index, Killip class, comorbidities, left ventricular ejection fraction, estimated glomerular filtration rate, baseline LDL-C, discharge medications, and procedural characteristics). The primary endpoint was 3-year major adverse cardiovascular events (MACE: all-cause death, recurrent myocardial infarction, or any coronary revascularization); the death/MI composite was a key secondary outcome. Post-discharge statin persistence, LDL-C target attainment, and longitudinal LDL-C profiles were additionally examined.

High-intensity statins were prescribed at discharge in 748 (32.3%) patients aged 65–74 years and 520 (28.4%) aged ≥ 75 years. In the 65–74-year group, high-intensity statins were associated with lower risks of MACE (overall cohort: 13.6% vs. 18.9%, adjusted HR 0.69, 95% CI 0.55–0.87, p < 0.01; matched: 13.7% vs. 18.1%, HR 0.71, 95% CI 0.54–0.92, p = 0.01) and the death/MI composite (overall: 7.9% vs. 11.3%, adjusted HR 0.69, 95% CI 0.51–0.94, p = 0.01; matched: 8.0% vs. 10.9%, HR 0.70, 95% CI 0.49–0.99, p = 0.04). In patients aged ≥ 75 years, neither composite outcome showed a statistically evident association with statin intensity. Post-discharge high-intensity statin persistence was comparable by age. Measured-only LDL-C < 70 mg/dL attainment was similar between age groups within each statin-intensity stratum, but when missing values were treated as non-attainment, lower attainment emerged in patients aged ≥ 75 years compared with those aged 65–74 years within each statin-intensity stratum, paralleling lower follow-up measurement rates. LDL-C separation and reductions in variability were also less distinct in this age group.

Discharge high-intensity statin therapy was associated with lower risks of the principal composite outcomes in patients aged 65–74 years but not in those aged ≥ 75 years. In very elderly patients, this attenuation may reflect residual geriatric confounding, incomplete LDL-C ascertainment, and uncertainty in sustained treatment exposure rather than absence of benefit, underscoring the need for prospective evaluation of target-oriented strategies in this population.