The bidirectional interaction of COVID-19 infections and lipoproteins.

COVID-19 infections decrease total cholesterol, LDL-C, HDL-C, and apolipoprotein A-I, A-II, and B levels while triglyceride levels may be increased or inappropriately normal for the poor nutritional status. The degree of reduction in total cholesterol, LDL-C, HDL-C, and apolipoprotein A-I are predictive of mortality. With recovery lipid/lipoprotein levels return towards pre-infection levels and studies have even suggested an increased risk of dyslipidemia post-COVID-19 infection.

Lipid and Lipoprotein Metabolism.

The exogenous lipoprotein pathway starts with the incorporation of dietary lipids into chylomicrons in the intestine. Chylomicron triglycerides are metabolized in muscle and adipose tissue and chylomicron remnants are formed, which are removed by the liver. The endogenous lipoprotein pathway begins in the liver with the formation of very low-density lipoprotein particles (VLDL).

Approach to patients with elevated low-density lipoprotein cholesterol levels.

Elevated low-density lipoprotein cholesterol (LDL-C) levels increase the risk of atherosclerotic cardiovascular disease (ASCVD) and lowering LDL-C levels reduces the risk of ASCVD. In patients with elevated LDL-C levels it is important to consider whether lifestyle, other medical conditions, medications, or genetic factors could be causing or contributing to the elevation. There are guidelines from various organizations outlining the approach to lowering LDL-C levels but while these guidelines agree on many issues there are numerous areas where recommendations are discordant.