NIH Halts Niacin, Statin Cholesterol Clinical Trial

June 1, 2011

The study was stopped because the niacin treatment allegedly did not reduce the risk of cardiovascular events, including heart attacks and stroke.

A clinical trial studying the effects of adding a high-dose, extended-release niacin supplement to statin treatment in people with cardiovascular disease has been halted 18 months ahead of schedule by the National Heart, Lung, and Blood Institute (NHLBI) of the National Institutes of Health. The study was stopped because the niacin treatment allegedly did not reduce the risk of cardiovascular events, including heart attacks and stroke.

The AIM-HIGH (Atherothrombosis Intervention in Metabolic Syndrome with Low LDL/High Triglycerides: Impact on Global Health) study enrolled 3414 participants in the United States and Canada who had a history of cardiovascular disease and who were taking a statin to keep their low-density lipoprotein (LDL, or “bad”) cholesterol low. Despite having low LDL levels, the subjects also had low high-density lipoprotein (HDL, or “good”) cholesterol levels as well as high triglyceride levels and a history of cardiovascular disease-the combination of which researchers believe put subjects at an increased risk of developing cardiovascular disease. The study looked to niacin, or vitamin B3, to help raise HDL levels and lower triglycerides.

“The rationale for the AIM-HIGH study was based in part on a large number of observational studies that consistently showed that low HDL cholesterol increases the risk of cardiovascular events in men and women, independent of high LDL cholesterol,” NHLBI stated.

The researchers said that while supplementation may have increased HDL cholesterol and lowered triglyceride levels compared to subjects who took a statin alone, the combination treatment still did not reduce fatal or non-fatal heart attacks or strokes.

The niacin dose given reached up to 2000 mg/day.

Notably, the study only looked at patients with unfavorable cardiovascular conditions. NHLBI notes, “Earlier studies of niacin had shown more favorable results. Unlike AIM-HIGH, the earlier studies were not designed specifically to evaluate the impact of raising HDL on the risk of cardiovascular events while maintaining excellent LDL control. Several other trials testing this hypothesis, including a large international trial of high-dose, extended-release niacin, are still ongoing.”

“The lack of effect on cardiovascular events is unexpected and a striking contrast to the results of previous trials and observational studies,” stated Jeffrey Probstfield, MD, the study’s co-principal investigator.