Early Low-Density Lipoprotein Cholesterol Target Attainment Is Associated With Fewer Recurrent Cardiovascular Events After Acute Myocardial Infarction: A Real-World Cohort Study

Survivors of acute myocardial infarction (AMI) face high risk of recurrent atherosclerotic cardiovascular disease (ASCVD) events within the first year after discharge, yet real-world achievement of guideline-recommended low-density lipoprotein cholesterol (LDL-C) targets <55 mg/dL remains limited. We conducted a retrospective cohort study of 12,815 adults hospitalized with type 1 AMI between January 1, 2015, and December 31, 2024, within the Rush University Health System in Chicago, Illinois, to evaluate the association between LDL-C <55 mg/dL attainment at approximately 6 months post-discharge and recurrent ASCVD events within 12 months. The primary outcome was a composite of non-fatal MI, unstable angina hospitalization, ischemic stroke, or unplanned coronary revascularization. Among 12,810 patients with available follow-up LDL-C data, 999 (7.8%) achieved the <55 mg/dL target. A total of 4,692 patients (36.6%) experienced a recurrent composite event within 12 months, and all-cause mortality at 12 months was 11.8%. The elevated event rate is attributable to the inclusive composite definition and to administrative coding practices in which hospital readmissions are frequently assigned AMI ICD-10 codes in patients with recent MI history, rather than reflecting true adjudicated MI recurrence. In unadjusted analyses, LDL-C goal attainment was paradoxically associated with higher odds of recurrent events (odds ratio [OR] 1.81; 95% confidence interval [CI] 1.59-2.06; p <0.001), consistent with confounding by indication: patients receiving the most intensive lipid-lowering therapy had the highest underlying cardiovascular risk. After multivariable adjustment for age, comorbidities, statin use, and admitting hospital, LDL-C <55 mg/dL attainment was associated with lower odds of recurrent events (adjusted OR 0.84; 95% CI 0.75-0.97; p = 0.007). LDL-C goal attainment was not significantly associated with all-cause mortality at 12 months (adjusted OR 0.91; 95% CI 0.73-1.14; p = 0.41), consistent with published literature requiring longer follow-up to demonstrate a mortality signal. These findings highlight persistent underattainment of guideline-recommended lipid targets and underscore substantial clinical inertia in post-AMI lipid management, with first LDL-C reassessment occurring at a mean of 85 days post-discharge while recurrent events occurred a mean of 49 days after admission. In conclusion, achievement of LDL-C <55 mg/dL within 6 months after AMI is independently associated with a meaningful reduction in recurrent ASCVD events in real-world practice, and the temporal mismatch between early post-discharge risk and delayed lipid assessment underscores the need for proactive, multidisciplinary care models to close this implementation gap.