Optimal low-density lipoprotein cholesterol target level in Korean acute myocardial infarction patients (<70 mg/dL vs. <55 mg/dL): Based on Korea acute myocardial infarction registry-National Institute of Health

Background: Current treatment guidelines for acute myocardial infarction (AMI) recommend lowering low density lipoprotein cholesterol (LDL-C). However, previous clinical studies among East Asian AMI patients failed to prove its clinical efficacy of lipid lowering therapy based on Western target LDL-C level. Thus, the purpose of this study is directly to compare the clinical outcomes of target LDL-C < 70 mg/dL and < 55 mg/dL and identify optimal target LDL-C level and in Korean AMI patients.

Methods and results: A total of 2198 AMI patients in Korea AMI Registry - National Institute of Health were enrolled. Patients were initially divided into LDL-C non-target group (n = 1115) and target group (n = 1083). Successful achievement of follow up target LDL-C was defined as <70 mg/dL and ≥ 50% reduction from baseline. Target group patients were additionally divided to <70 mg/dL group (n = 698) and <55 mg/dL group (n = 385). Propensity score matching analysis was done in non-target vs. target group and <70 mg/dL vs. <55 mg/dL group. In the matched population, the risk of 3 years major adverse cardiac event (MACE) (13.0% vs 9.8%, HR: 0.73; 95% CI: 0.56-0.96; p = 0.025) was higher in non-target group patients. However, the risk of MACE was similar in <70 mg/dL and < 55 mg/dL group patients (10.0% vs 8.1%, HR: 0.75, 95% CI: 0.46-1.22; p = 0.247).

Conclusion: In the present study, target LDL-C level of <70 mg/dL and ≥ 50% reduction from baseline level was associated with better clinical outcomes in Korean AMI patients. However, further lowering target LDL-C level of <55 mg/dL showed no additional benefits.