Background— Niacin reduces coronary heart disease morbidity and mortality when taken either alone or in combination with statins; however, the incremental impact of adding niacin to background statin therapy is unknown.

Methods and Results— This was a double-blind randomized placebo-controlled study of once-daily extended-release niacin (1000 mg) added to background statin therapy in 167 patients (mean age 67 years) with known coronary heart disease and low levels of high-density lipoprotein cholesterol (HDL-C; <45 mg/dL). The primary end point was the change in common carotid intima-media thickness (CIMT) after 1 year. Baseline CIMT (0.884±0.234 mm), low-density lipoprotein cholesterol (89±20 mg/dL), and HDL-C (40±7 mg/dL) were comparable in the placebo and niacin groups. Adherence to niacin exceeded 90%, and 149 patients (89.2%) completed the study. HDL-C increased 21% (39 to 47 mg/dL) in the niacin group. After 12 months, mean CIMT increased significantly in the placebo group (0.044±0.100 mm; P<0.001) and was unchanged in the niacin group (0.014±0.104 mm; P=0.23). Although the overall difference in IMT progression between the niacin and placebo groups was not statistically significant (P=0.08), niacin significantly reduced the rate of IMT progression in subjects without insulin resistance (P=0.026). Clinical cardiovascular events occurred in 3 patients treated with niacin (3.8%) and 7 patients treated with placebo (9.6%; P=0.20).

Conclusions— The addition of extended-release niacin to statin therapy slowed the progression of atherosclerosis among individuals with known coronary heart disease and moderately low HDL-C.