Niacin Therapy Increases High-Density Lipoprotein Particles and Total Cholesterol Efflux Capacity But Not ABCA1-Specific Cholesterol Efflux in Statin-Treated Subjects

OBJECTIVE—We investigated relationships between statin and niacin/statin combination therapy and the concentration of high-density lipoprotein particles (HDL-P) and cholesterol efflux capacity, 2 HDL metrics that might better assess cardiovascular disease risk than HDL-cholesterol (HDL-C) levels. APPROACH—In the Carotid Plaque Composition Study, 126 subjects with a history of cardiovascular disease were randomized to atorvastatin or combination therapy (atorvastatin/niacin). At baseline and after 1 year of treatment, the concentration of HDL and its 3 subclasses (small, medium, and large) were quantified by calibrated ion mobility analysis (HDL-PIMA). We also measured total cholesterol efflux from macrophages and ATP-binding cassette transporter A1 (ABCA1)–specific cholesterol efflux capacity. RESULTS—Atorvastatin decreased low-density lipoprotein cholesterol by 39% and raised HDL-C by 11% (P=0.0001) but did not increase HDL-PIMA or macrophage cholesterol efflux. Combination therapy raised HDL-C by 39% (P