The association of repeatedly measured low-density lipoprotein cholesterol and all-cause mortality and cardiovascular disease in dyslipidemic patients: A longitudinal study

Background and aims: This study aimed to evaluate the association between very low levels of low-density lipoprotein (LDL) cholesterol and subsequent clinical outcomes among dyslipidemic patients. Methods: A retrospective longitudinal study was conducted at a large teaching hospital in Tokyo, Japan, from 2005 to 2018. We included all dyslipidemic adult patients who were followed up at the department of endocrinology. The primary outcome was all-cause mortality and the secondary outcome was cardiovascular disease. We compared the development of these outcomes according to LDL cholesterol categories through longitudinal analyses adjusting for potential confounders. Results: We included total of 4485 dyslipidemic patients. The mean patient age (standard deviation) was 58.4 (12.2) years, and 2286 patients were men. During a median follow-up of 5.3 (interquartile range 2.2-9.6) years, 252 (5.7%) patients died (25[0.6%] were cardiovascular deaths) and 912 (20.3%) patients developed cardiovascular diseases. Multivariable longitudinal analyses showed that the very low LDL cholesterol group (b60 mg/dl) had significantly higher all-cause mortality than the normal LDL cholesterol group (100-140 mg/ dl) (odds ratio[OR] 1.96, 95%confidence interval [CI]:1.22-3.16). Among high-risk patients for atherosclerotic cardiovascular disease (ASCVD), very low LDL cholesterol was significantly associated with increased all-cause mortality (OR 2.61, 95%CI: 1.12-6.10) but decreased incidence of cardiovascular disease (OR 0.47, 95%CI: 0.23-0.93). Conclusions: Very low LDL cholesterol is associated with increased all-causemortality but not statistically associated with cardiovascular disease incidence among dyslipidemic patients, regardless of risk. When patients were stratified according to ASCVD risk, this association was more obvious among high-risk patients. (c) 2020 Elsevier B.V. All rights reserved.