High density lipoproteins and kidney function: the friend turned foe?

The crucial role of low density lipoprotein cholesterol (LDL-C) in cardiovascular disease (CVD) and mortality has been extensively demonstrated, and thus reducing LDL-C is one of the key therapeutic approaches for cardiovascular risk reduction (1). However, the exact role of high density lipoproteins (HDL) is still an enigma and as research expands it is getting even more complicated. In this scenario, the work of Bowe and co-workers (2) adds a new piece of this puzzle by demonstrating the existence of an U-shape distribution of the risk of all-cause mortality in relation to HDL-C levels with a reduced risk only in those with intermediate HDL-C levels (between 25 and 50 mg/dL). This relation between HDL-C and all-cause mortality was previously reported, specifically in hemodialysis patients (3). Nevertheless, Bowe et al. (2) have investigated patients without a previous history of end-stage renal disease (ESRD), dialysis or kidney transplant, further demonstrating the U-shape association between HDL-C levels and mortality even in the absence of established kidney disease.