Total cholesterol/HDL-cholesterol ratio discordance with LDL-cholesterol and non-HDL-cholesterol and incidence of atherosclerotic cardiovascular disease in primary prevention: The ARIC study

AIMS: The total cholesterol (TC)/high-density lipoprotein (HDL) cholesterol ratio may carry additional information not available in more commonly used single cholesterol measures. Analysis of discordance between lipid parameters might help assess the impact of such additional information on the risk of atherosclerotic cardiovascular disease. We aimed to investigate the role of the TC/HDL-cholesterol ratio in determining atherosclerotic cardiovascular disease risk when discordant with low-density lipoprotein (LDL) cholesterol and non-HDL-cholesterol. METHODS: We studied 14,403 Atherosclerosis Risk in Communities (ARIC) study participants who were free of atherosclerotic cardiovascular disease at baseline. TC/HDL-cholesterol discordance with LDL-cholesterol (estimated by the novel Martin/Hopkins method) and non-HDL-cholesterol was assessed at five visits and determined by being at or above the median for each lipid parameter. We constructed Cox proportional hazard models to estimate the risk for incident atherosclerotic cardiovascular disease events associated with each lipid concordance/discordance category using a time-varying approach. RESULTS: Mean age of participants was 54.1 years, 56% women and 25% black. There were 2634 atherosclerotic cardiovascular disease events over a median (interquartile range) follow-up of 24.2 (16.0-25.4) years. Among individuals with LDL-cholesterol and non-HDL-cholesterol less than the median, 26% and 21% had discordant TC/HDL-cholesterol at or above the median, respectively. These individuals had a 24% (hazard ratio (HR) 1.24, 95% confidence interval (CI) 1.09, 1.41) and 29% (HR 1.29, 95% CI 1.13, 1.46) greater risk of incident atherosclerotic cardiovascular disease, respectively, compared to those with TC/HDL-cholesterol less than the median after multivariable adjustment. In individuals with diabetes with LDL-cholesterol or non-HDL-cholesterol less than the median, discordant TC/HDL-cholesterol at or above the median was more prevalent at 48% and 38%, respectively. CONCLUSION: Clinically significant discordance exists between TC/HDL-cholesterol, available from the standard lipid profile, and the routinely used non-HDL-cholesterol and LDL-cholesterol. Such discordance may help inform atherosclerotic cardiovascular disease risk management, particularly in individuals with diabetes in whom discordance is more common.