APOA2 and chronic kidney disease: HDL capacity to promote cholesterol efflux from macrophages, a parameter inversely associated with the likelihood of coronary artery disease independently of HDL-c levels [34], is impaired in CKD patients [33,35], likely due to the HDL enrichment in SSA1 and apoC-III and the depletion in apoA-I, apoA-II, and phospholipids [20,36,37].