Niacin Not Beneficial in Patients at Goal With Statins: NIA Plaque

November 18, 2009

November 18, 2009 (Orlando, Florida) The addition of niacin to statin therapy in secondary-prevention patients resulted in a significant improvement in LDL- and HDL-cholesterol levels but failed to significantly alter atherosclerotic disease progression as measured by MRI, compared with statin therapy alone.

The results, from the NIA Plaque study, are in contrast with the findings from the Arterial Biology for the Investigation of the Treatment Effects of Reducing Cholesterol: HDL and LDL Treatment Strategies in Atherosclerosis (ARBITER 6-HALTS) study and with a recent imaging study showing that niacin helped with plaque regression when used on top of optimized statin therapy, but investigators say the patient populations differ significantly.

Lead researcher Dr Christopher Sibley (Johns Hopkins University Medical Center, Baltimore, MD) told heartwire that patients in NIA Plaque were older and had less diabetes mellitus and glucose intolerance, but, most important, had higher HDL-cholesterol levels when randomized to extended-release niacin than those in the ARBITER 6 study.

"Treating these high-risk patients to their target LDL-cholesterol levels based on the cholesterol guidelines results in significant reductions in the carotid arterial wall volume from baseline, but there was no significant difference between the two treatment arms," said Sibley. "It's essentially a win for the National Cholesterol Education Program Adult Treatment Panel III [NCEP ATP III] guideline, focusing on LDL lowering with statin therapy. Previous trials have certainly shown that niacin has multiple effects, and we know it affects multiple lipid parameters, but our results show that those effects were effectively dwarfed by the effects of the statin."

Secondary-Prevention Patients With Higher HDL Levels

Presenting the results at the American Heart Association (AHA) 2009 Scientific Sessions, Sibley said the trial was designed to determine whether there would be any additional benefit of raising HDL-cholesterol levels on atherosclerotic disease progression in older secondary-prevention patients, compared with optimizing statin therapy.

In total, 145 patients with clinically evident atherosclerosis were randomized to 1500 mg daily of extended-release niacin or to placebo. All patients were treated with a statin as needed to reach NCEP ATP III LDL-cholesterol targets. After 18 months of follow-up, extended-release niacin resulted in significant increases in HDL cholesterol and a significant decrease in LDL cholesterol. Statins alone resulted in significant reductions in LDL cholesterol but did not positively affect HDL-cholesterol levels.

NIA Plaque: Change in Lipid Parameters From Baseline to 18 Months

Lipid measure (mg/dL) Statin + placebo, baseline Statin + placebo, 18 mo Statin + extended-release niacin, baseline Statin + extended-release niacin, 18 mo p (between groups)
Total cholesterol 166 152 174 150 0.65
LDL cholesterol 86 77 88 67 0.03
HDL cholesterol 55 49 55 58 <0.001
Triglycerides 123 93 115 84 0.02

Regarding the primary end point, the change in the internal carotid artery wall volume, both treatment strategies resulted in significant reductions from baseline, but there was no significant difference between the two treatment arms, nor were there any significant differences between treatments for numerous secondary MRI outcomes, including measurements of the lipid core.

Niacin and HDL Cholesterol at the AHA

At the AHA meeting, there is no shortage of news on HDL cholesterol, especially given the attention garnered by the ARBITER 6-HALTS study. Another study, also reported by heartwire , showed that low levels of HDL cholesterol, even among statin-treated patients, are associated with a significantly increased risk of cardiovascular disease, particularly the risk of MI.

To heartwire , Sibley said the differences in the results are explained by the patients studied. In contrast to the ARBITER 6-HALTS study, the ARBITER 2 study, and the IMT study published by the Oxford researchers [1], there was no "HDL-cholesterol cap" in the NIA Plaque trial, and,as a result, the average baseline HDL cholesterol was 55 mg/dL, higher than the 42 mg/dL reported in ARBITER 6-HALTS. In the Oxford study, patients were included if they had baseline HDL-cholesterol levels <40 mg/dL.

"Those studies show a beneficial effect of extended-release niacin in general, but we studied patients above the low HDL-cholesterol cap," said Sibley. "In terms of expanding the use to a more general population, the results do not support it."


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