In the trial, more than 3,400 patients averaging 64 years of age were randomly assigned to high-dose niacin or a placebo. Those in the niacin arm of the trial took Abbott Laboratories' Niaspan, a time-released form of niacin that contains a much higher dose of niacin than is found in over-the-counter supplements.
All of the participants also took the cholesterol-lowering statin drug Zocor (simvastatin).
As expected, participants who took Niaspan for the 32 months of the trial saw their blood levels of HDL cholesterol rise and their triglycerides lower, compared with those who took a statin alone.
But the boost in HDL failed to translate to any reduction in heart attacks or strokes, the team said. Nor did it lower the rate of hospitalizations for heart disease or procedures to open blocked cardiac arteries, according to the NHLBI.
Worse, more people taking niacin had strokes than those on a statin alone, the researchers found. In fact, 28 participants taking Niaspan suffered strokes, compared with 12 in the placebo group. Nine of the strokes in the Niaspan group happened to participants who had stopped using the drug at least two months and up to four years before their stroke.
Earlier studies had not shown any connection between high-dose niacin and stroke risk, Shurin said. Why the uptick in strokes was seen in this study isn't clear, she said.
Shurin cautioned people who take supplemental niacin not to stop taking it. They might want to talk with their doctor, she said. But this study is no reason to change what they are doing, she added.
All those in the study have been notified of the results and will be scheduled for clinic visits within the next several months. They will also be followed for 12 to 18 months.
The trial was funded by the NHLBI with support from Abbott Laboratories, which provided the Niaspan. Drug maker Merck Pharmaceuticals
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