Correlation study between small dense low density lipoprotein cholesterol and its ratio to high density lipoprotein cholesterol and acute coronary syndrome

Abstract

Objective To investigate the predictive effects of small dense low density lipoprotein cholesterol (sdLDL-C) level and sdLDL-C/high density lipoprotein cholesterol (HDL-C) ratio on the occurrence in patients with acute coronary syndrome (ACS). Methods Two hundred and sixty-eight patients with acute chest pain and diagnosed as ACS according to the clinical symptoms, changes in electrocardiogram and myocardial enzymes, and coronary angiography from November 2017 to April 2018 were enrolled. One hundred and thirty-four cases of unstable angina (UA) and 134 cases of acute myocardial infarction (AMI) were included. Meanwhile, 66 patients with non-ACS were selected as the control group. They baseline data were matched with those of ACS in the same period. Results The sdLDL-C levels and sdLDL-C/HDL-C of ACS patients were significantly increased [0.88(0.70, 1.09) mmol/L vs. 0.61(0.41, 0.84) mmol/L, 0.98(0.72, 1.30) vs. 0.58(0.40, 0.86)]. The sdLDL-C levels and sdLDL-C/HDL-C of AMI group were higher than those of UA group [0.94(0.82, 1.21) mmol/L vs. 0.78 (0.61, 0.98) mmol/L, 1.10(0.79, 1.40) vs. 0.86 (0.62, 1.19)], while those of UA group were also higher than those of the control group [0.78(0.61, 0.98) mmol/L vs. 0.61(0.41, 0.84) mmol/L, 0.86(0.62, 1.19) vs. 0.58(0.40, 0.86)]. There were significant differences (P<0.01). Logistic regression analysis showed that sdLDL-C level was an independent risk factor for ACS prediction. Compared with those of the control group, the OR values of ACS group, UA group and AMI group were respectively 26.85, 15.19 and 74.40. Correlation analysis showed that sdLDL-C was significantly positively correlated with TC and LDL-C levels (r=0.697, 0.684, P<0.01), while it controlled TC and LDL-C levels, and sdLDL-C levels were still significantly positively correlated with ACS (r=0.185, P=0.001). ROC analysis revealed that sdLDL-C ≥ 0.613 mmol/L had a sensitivity of 86.6% and specificity of 51.5%, and a sdLDL-C/HDL-C ≥ 0.938 mmol/L had a sensitivity of 53.7% and specificity of 87.9%. ROC curve was used to analyze AMI in ACS group, and the best threshold sdLDL-C=0.732 mmol/L divided the cases into low-risk groups and high-risk groups. Logistic regression analysis showed that, compared with the low-risk groups, the relative risk estimates of the AMI in the high-risk group was 4.84, after other indicators were adjusted. Conclusions sdLDL-C levels and sdLDL-C/HDL-C are closely related to the occurrence of ACS. As independent risk factors, they are risk assessment predictors for ACS. Key words: Coronary disease; Small dense low density lipoprotein cholesterol; High density lipoprotein cholesterol