Low-Density Lipoprotein Cholesterol is Inversely Associated with All-Cause Mortality of Patients in the Coronary Care Unit

Yingbei Weng, Ripeng Yin, Lala Qian, Zhi Chen, Jie Wang, Huaqiang Xiang, Yangjing Xue, Kangting Ji, Xueqiang Guan Department of Cardiology, The Second Affiliated Hospital and Yuying Children’s Hospital, Wenzhou Medical University, Wenzhou, 325000, Zhejiang, People’s Republic of ChinaCorrespondence: Kangting Ji; Xueqiang GuanDepartment of Cardiology, The Second Affiliated Hospital and Yuying Children’s Hospital, Wenzhou Medical University, Xueyuanxi Road, No. 109, Wenzhou, 325000, Zhejiang, People’s Republic of ChinaEmail jikt@wzmc.edu.cn; wzsgxq@163.comObjective: The aims of this study were to investigate the relationship between low-density lipoprotein cholesterol (LDL-C) levels and all-cause mortality in coronary care unit (CCU) patients, adjusting for a wide range of potential confounding factors, to examine the potential of LDL-C in predicting the prognostic value of CCU patients.Methods: Clinical data were extracted from Medical Information Mart for Intensive Care-III database (MIMIC-III database version v.1.4). Baseline data were collected within 24 hours after the patient was first admitted to the hospital. The primary endpoint of our study is 30-day all-cause mortality. The secondary endpoints are 90-day and one-year all-cause mortality and infections. Cox proportional hazard regression and propensity score-matched (PSM) analysis were used to analyze the association between LDL-C levels and prognostic value of CCU patients.Results: We included a total of 1476 patients with an average age of 66.7 ± 14.1 years (66% male). For 30-day all-cause mortality, the hazard ratio (95% confidence interval) of high LDL-C level group (≥ 55 mg/dl) was 0.42 (0.29, 0.62), which was compared with low LDL-C level group (< 55 mg/dl) in unadjusted model. After adjusting for age, gender and race, the association still existed (P < 0.05), and the HR (95% CI) was 0.49 (0.33, 0.72). Further adjustment of possible covariates showed similar correlation (P < 0.05), and HR (95% CI) was 0.65 (0.43, 0.97). Similar correlations were observed for 90-day and one-year all-cause mortality. The relationship between all-cause mortality and LDL-C levels in CCU patients was further verified by propensity score-matched (PSM) analysis. In addition, the higher the LDL-C level, the lower the risk of infection, odds ratio (OR) values in the three models were less than 1 (P < 0.05).Conclusion: Our data suggest that high LDL-C level is associated with a reduced risk of 30-day, 90-day, and one-year mortality of patients in the CCU. And this result is still stable in the PSM model. The results need to be verified in prospective trials.Keywords: low-density lipoprotein cholesterol, coronary care unit, all-cause mortality, cardiovascular diseas