Long-term outcomes according to absolute value vs. percentage reduction in low-density lipoprotein cholesterol levels after acute myocardial infarction

Backgrounds/aims Real-world data are limited regarding long-term outcomes in terms of absolute follow-up values of low-density lipoprotein cholesterol (LDL-C) vs. percentage reductions from baseline after LDL-C-lowering therapy for patients with acute coronary syndrome. We aimed to investigate the associations between 5-year clinical outcomes and absolute follow-up LDL-C levels or percentage reductions from baseline using a nationwide Korea Acute Myocardial Infarction Registry (KAMIR). Methods Of 13,662 patients from the KAMIR–National Institutes of Health database, we identified 6,248 patients who had documented LDL-C levels at baseline and during 18 months of follow-up. The primary outcome was major adverse cardiovascular events (MACE; a composite of nonfatal stroke, nonfatal myocardial infarction, repeat revascularization, and all-cause death) at 5 years. Results In the analysis of absolute follow-up time-weighted average LDL-C levels (<55, 55–69, 70–89, and ≥90 mg/dL), there was a U-shaped trend of MACE incidence (10.8% vs. 9.3% vs. 10.0% vs. 13.2%, P = 0.003). In the analysis of the percentage LDL-C reduction from baseline, greater reductions were associated with lower MACE risk. In a multivariable Cox time-to-event analysis with LDL-C < 50% reduction from baseline as the reference, ≥50% LDL-C reduction from baseline was independently associated with a decreased incidence of MACE (adjusted hazard ratio, 0.76; 95% confidence interval, 0.62–0.92). Conclusion This study involving 6,248 AMI patients demonstrated that the greater the LDL-C reduction from baseline, the lower the risk of MACE. However, there was no clear decreasing trend in the risk of MACE when absolute follow-up LDL-C levels were lowered from around 70 mg/dL