Impact of measured or calculated small dense LDL cholesterol compared with apolipoprotein B or non-HDL cholesterol for long-term secondary prevention in patients with stable coronary artery disease

Abstract Background This study was aimed to investigate whether directly measured small dense low-density lipoprotein cholesterol (D-sdLDL-C) can predict long-term coronary artery disease (CAD) events compared with LDL-C, non–high-density lipoprotein cholesterol (non-HDL-C), apolipoprotein B (apoB), and estimated sdLDL-C (E-sdLDL-C) determined by Sampson’s equation in patients with stable CAD. Methods D-sdLDL-C measured at Showa University, and E-sdLDL-C were evaluated in 790 male and 244 female patients with stable CAD. CAD events defined as sudden cardiac death, onset of acute coronary syndrome, and/or need for coronary revascularization were monitored for 12 years. Cut-points of D-sdLDL-C, E-sdLDL-C, LDL-C, non-HDL-C, and apoB were determined by receiver operating characteristic curves. Results CAD events were observed in 238 male and 67 female patients. The Kaplan–Meier event-free survival curves showed that patients with D-sdLDL-C ≥32.1 mg/dL had an increased risk for CAD events (chi-square from log-rank test = 7.23), whereas risk in patients with E-sdLDL-C ≥36.2 mg/dL was not. In the group with high D-sdLDL-C, the multivariable-adjusted hazard ratio (HR) was 1.47, 95% confidence interval (CI) 1.15-1.89, and it remained significant after adjustment for LDL-C, non-HDL-C, or apoB. These results remained significant in the patients treated with statin. HRs for high LDL-C, non-HDL-C, or apoB were not statistically significant after adjustment for high D-sdLDL-C. The high D-sdLDL-C enhanced risk of high LDL-C, non-HDL-C, and apoB (HR 1.73, 95%CI 1.27-2.37). Conclusions: High D-sdLDL-C can predict long-term recurrence of CAD in stable CAD patients independently of apoB and non-HDL-C by distinguishing the patients at high risk. D-sdLDL-C is an independent risk-enhancer for secondary CAD prevention whereas E-sdLDL-C is not.Figure