Differential effects of simvastatin and bezafibrate on apolipoprotein-defined high-density lipoprotein subfractions in patients with hypercholesterolemia

Our study goal was to determine whether two hypolipidemic drugs, each with a different mechanism of action, have different effects on serum levels of high-density lipoprotein (HDL) subpopulations, as defined by the presence of apolipoprotein (apo) A-I (Lp A-I) and of both apo A-I and A-II (Lp A-I:A-II). Nineteen patients with primary hypercholesterolemia were treated for 3 months with simvastatin 20 mg once daily and 19 patients were treated with sustained-release bezafibrate 400 mg/d. Seventeen patients following a stable low-cholesterol, low-fat diet served as a reference group. In both the diet-only and simvastatin groups, no significant change in HDL-cholesterol (HDL-C), apo A-I, apo A-II, Lp A-I, and Lp A-I:A-II occurred; in the bezafibrate group, HDL-C increased by 10%, apo A-I by 15%, and apo A-II by 43%. Lp A-I decreased by 15% and Lp A-I:A-II increased by 33% in the bezafibrate group. The relevance to the risk of coronary heart disease of the decrease of Lp A-I after bezafibrate therapy is uncertain, although Lp A-I - but not Lp A-I:A-II - has been suggested to account for the protective role of HDL.