Impact of initial very low-level low-density lipoprotein cholesterol on the prognosis of acute myocardial infarction patients

Background: Cholesterol control with statins has been shown to have beneficial effects in coronary artery disease. However, the relationship between initial very low low-density lipoprotein (LDL) cholesterol levels and long-term clinical outcomes in patients with acute myocardial infarction (AMI) remains unclear. Methods: A total of 8741 (mean age: 64.6 ± 12.7 years, men) consecutive AMI patients treated with drug-eluting stents were entered into the Korea Acute Myocardial Infarction Registry from November 2011 to December 2015. Patients were divided into six groups according to whether they were taking statins (on-statin group) or not (statin naive group) and depending on their LDL cholesterol level at admission (<70, 70-99, 100-129, 130-159, >160 mg/dl). Clinical outcomes at 24 months in patients with AMI were examined. Results: The incidence of risk factors including hypertension, diabetes, coronary artery disease and heart failure was lower as LDL cholesterol increased, except in the on-statin group. Clinical outcomes, including total mortality at 24 months, showed better outcomes in those with high LDL cholesterol than those with low LDL cholesterol, except in the statin group. In the statin-naïve group, the higher the LDL cholesterol level, the higher the rate of 24-month survival. In a Cox regression model, initial low LDL cholesterol was an independent predictor of mortality at 24 months after adjusting for baseline confounding factors. Conclusions: At admission, a very low LDL cholesterol level (<70 mg/dL) in statin-naïve AMI patients undergoing percutaneous coronary intervention was independently associated with higher mortality at 24 months.