Long-Term Outcomes According to Absolute Value Versus Percentage Reduction in Low-Density Lipoprotein Cholesterol Levels After Acute Myocardial Infarction

KYUNG HOON CHO^1,2Jung Ho Yang¹Sang Yeub Lee³Min-Ho Shin¹Seok Oh²Min Chul Kim^1,2Doo Sun Sim^1,2Young Joon Hong^1,2Ju Han Kim^1,2Youngkeun Ahn^1,2Jang Hoon Lee⁴Ju-Seung Kwun⁵Young-Hoon Jeong³Joo-Yong Hahn⁶Jin Yong Hwang⁷Myung Ho Jeong^1,8*Weon Kim^9*

• ¹Chonnam National University Medical School, Gwangju, Republic of Korea
• ²Chonnam National University Hospital, Dong-gu, Republic of Korea
• ³Chung-Ang University Gwangmyeong Hospital, Gwangmyeong-si, Republic of Korea
• ⁴Kyungpook National University School of Medicine, Daegu, Republic of Korea
• ⁵Seoul National University College of Medicine Department of Internal Medicine, Seoul, Republic of Korea
• ⁶Sungkyunkwan University School of Medicine at Samsung Medical Center Cancer Center Library of Medicine, Gangnam-gu, Republic of Korea
• ⁷Gyeongsang National University College of Medicine, Jinju-si, Republic of Korea
• ⁸Gwangju Veterans Hospital, Gwangsan-gu, Republic of Korea
• ⁹Kyung Hee University Medical Center, Seoul, Republic of Korea

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) versus 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 6248 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% versus 9.3% versus 10.0% versus 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 6248 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