Objective  To investigate the relationship between small dense low density lipoprotein cholesterol (sdLDL-C) and prognosis of elderly patients with coronary heart disease.

  Methods  A total of 80 patients with coronary heart disease from October 2019 to October 2020 in the Second Affiliated Hospital of Xinjiang Medical University were selected and divided into statin group (n=40) and non-statin group (n=40). In addition, 40 non-coronary heart disease elderly patients with physical examination at the same time were selected as control group. Serum sdLDL-C, lipoprotein associated phospholipase A2 (Lp-PLA2), total cholesterol (TC), triglyceride (TG), low density lipoprotein cholesterol (LDL-C), high density lipoprotein cholesterol (HDL-C), lipoprotein (a)Lp(a)and neutrophil to lymphocyte ratio (NLR) of the three groups were measured, the occurrence of major adverse cardiovascular events (MACE) in patients with coronary heart disease was recorded, and the risk factors of MACE in patients with coronary heart disease were analyzed.

  Results  There were significant differences in the levels of sdLDL-C, Lp-PLA2, TG, TC, HDL-C, LDL-C and Lp(a) among the statin group, the control group and non-statin group (P<0.05). Pearson correlation analysis showed that the level of serum sdLDL-C in all patients with coronary heart disease was positively correlated with LDL-C, TG and TC (P<0.05); the level of serum sdLDL-C in patients with statins was positively correlated with TC and LDL-C (P<0.05); serum sdLDL-C level was positively correlated with TC and LDL-C in patients without statins (P<0.05); the level of serum sdLDL-C in the controls was positively correlated with LDL-C, TG and TC (P<0.05). After adjusting for the effects of age, gender, TC, TG and LDL-C, the levels of serum sdLDL-C (OR=5.677, 95%CI, 1.008~31.983, P=0.049) and Lp(a) (OR=1.007, 95%CI, 1.001~1.013, P=0.015) were independent risk factors for MACE in patients with coronary heart disease.

  Conclusion  Regular administration of statins for a long time can effectively reduce the levels of serum sdLDL-C, Lp-PLA2, TG, TC, LDL-C and Lp(a) and increase the level of HDL-C in patients with coronary heart disease, in which the levels of sdLDL-C and Lp(a) can be used as independent risk factors for MACE in patients with coronary heart disease.