[Effect of LDL-C/HDL-C ratio on severity of coronary artery disease and 2-year long-term prognosis in elderly patients with coronary heart disease].

<b>Objective:</b> To explore the effect of low density lipoprotein cholesterol (LDL-C)/high density lipoprotein cholesterol (HDL-C) ratio on the severity of coronary artery disease and 2-year adverse events in elderly patients with coronary heart disease. <b>Methods:</b> This prospective, multicenter, observational cohort study was from the prospective observational multicenter cohort for ischemic and hemorrhage risk in coronary artery disease patients (PROMISE) study, in which 18 701 patients with coronary heart disease (CHD) were included from January 2015 to May 2019. Among them, 6 770 elderly patients with CHD were enrolled in the current study. According to the median of LDL-C/HDL-C ratio (2.1), the patients were divided into two groups: low LDL-C/HDL-C group (LDL-C/HDL-C≤2.1, <i>n</i>=3 346) and high LDL-C/HDL-C group (LDL-C/HDL-C2.1, <i>n</i>=3 424). Baseline data and 2-year outcomes (including death, myocardial infarction, revascularization, stroke) were collected and analyzed in order to found the differences of elderly CHD patients with different LDL-C/HDL-C levels, and explore the correlation between LDL-C/HDL-C ratio with the severity of coronary artery disease and prognosis using Cox multivariate regression analysis. <b>Results:</b> Patients in the low LDL-C/HDL-C group were older [(71.9±5.5) vs (71.5±5.4) years old, <i>P</i>=0.003], and there was no statistically significant difference in the proportion of males between the two groups (61.9% vs 63.4%,<i>P</i>=0.208). The indicators reflecting the severity of coronary artery lesions, including the number of target lesions, the number of coronary artery disease, preoperative SNYTAX score, and the proportion of triple-vessel disease (1.01±0.81 vs 0.88±0.78, 2.28±0.81 vs 2.14±0.83, 16.05±10.67 vs 13.59±9.49, 49.0% vs 41.0%, respectively, all <i>P</i>0.05) were higher in the high LDL-C/HDL-C group. The 2-year follow-up showed that there was no statistically significant difference in the incidence of major adverse cardiovascular and cerebrovascular events (MACCE), all-cause mortality, cardiac death, myocardial infarction, and revascularization between the high LDL-C/HDL-C ratio group and the low LDL-C/HDL-C ratio group. Compared by gender, the incidence of all-cause death and cardiac death in the high LDL-C/HDL-C group of female patients were higher than the low LDL-C/HDL-C group (6.9% vs 4.8%, 5.3% vs 3.7%, both <i>P</i>0.05, respectively); There was no statistically difference in the incidence of adverse events between the two groups of male patients. Cox multivariate regression analysis showed that, regardless of gender, the LDL-C/HDL-C ratio was not a risk factor for 2-year MACCE in elderly patients with CHD (male: <i>HR</i>=1.21, 95%<i>CI</i>: 0.87-1.69; female: <i>HR</i>=0.96, 95%<i>CI</i>: 0.65-1.43;total: <i>HR</i>=1.09, 95%<i>CI</i>: 0.85-1.39,all <i>P</i>0.05). <b>Conclusions:</b> The severity of coronary artery disease is higher in elderly patients with high LDL-C/HDL-C ratio than in those with low LDL-C/HDL-C ratio. The LDL-C/HDL-C ratio is not a risk factor for 2-year adverse cardiovascular and cerebrovascular events in elderly patients with coronary heart disease. However, the incidences of 2-year adverse cardiovascular events of female patients with high LDL-C/HDL-C ratio are higher than patients with low LDL-C/HDL-C ratio.