Niacin and statin combination therapy for atherosclerosis regression and prevention of cardiovascular disease events: reconciling the AIM-HIGH (Atherothrombosis Intervention in Metabolic Syndrome With Low HDL/High Triglycerides: Impact on Global Health Outcomes) trial with previous surrogate endpoint trials.

Despite substantial risk reductions targeting low-density lipoprotein cholesterol with statins, there remains significant residual risk as evidenced by incident and recurrent cardiovascular disease (CVD) events among statin-treated patients. Observational studies have shown that low levels of high-density lipoprotein cholesterol (HDL-C) are associated with increased CVD risk. It remains unclear whether strategies aimed at increasing HDL-C in addition to background statin therapy will further reduce risk. The AIM-HIGH (Atherothrombosis Intervention in Metabolic Syndrome With Low HDL/High Triglycerides: Impact on Global Health Outcomes) trial, which compared combined niacin/simvastatin with simvastatin alone, failed to demonstrate an incremental benefit of niacin among patients with atherosclerotic CVD and on-treatment low-density lipoprotein cholesterol values <70 mg/dl, but this study had some limitations. Previously, small randomized, clinical trials of niacin plus statins showed that modest regression of carotid atherosclerosis is possible in individuals with CVD, CVD risk equivalents, or atherosclerosis. This viewpoint summarizes these imaging trials studying niacin and places them in the context of the failure of AIM-HIGH to support the HDL-C-increasing hypothesis.