Niacin and the heart
Posted by medconsumers on December 11, 2011
Niacin, in very high doses, has long bridged the gap between mainstream and alternative medicine. Many people with heart disease regularly take this form of vitamin B to prevent a first heart attack or avoid having another one. Though niacin is available over the counter, the more expensive branded product called Niaspan is often prescribed by cardiologists as the better way to raise blood levels of “good cholesterol” (high-density lipoprotein). The assumption that raising HDL cholesterol with niacin will spare anyone a heart-related disaster, however, had never been put to a good scientific test. That is, until now.
In May, the first large clinical trial designed to determine whether high-dose niacin can benefit people with heart disease had to be stopped 18 months earlier than planned. Reason: The addition of Niaspan to the usual statin drug therapy given to heart patients did not lower the chances of having a heart attack or a stroke. All 3,414 study participants, whose average age was 64 years, had been randomly assigned to take either Niaspan (extended release niacin, 1500-2000 mg daily) or a placebo.
Another, more alarming, reason why this trial was stopped early can be found in the press release issued on May 26, 2011 by its funding source, the National Heart, Lung, and Blood Institute, “…a small and unexplained increase in ischemic stroke rates” was noted in the participants taking Niaspan. This might come as a surprise to many people. After all, niacin is a vitamin—vitamin B3 to be exact.
Now, the final results of this halted trial, known by the acronym AIM-HIGH, were published recently in The New England Journal of Medicine: “Among patients with atherosclerotic cardiovascular disease, … there was no incremental clinical benefit from the addition of niacin to statin therapy during a 36-month follow-up period, despite significant improvements in HDL cholesterol and triglyceride levels.” In other words, the heart patients taking Niaspan had greater improvements in their blood test results, compared to the heart patients who were not taking niacin. But there was no difference between the Niaspan group and the placebo group in terms of outcomes such as heart attack, stroke, and the need for heart surgery.
As for the increased rate of ischemic stroke shown in the study participants taking Niaspan, this was acknowledged by the authors of the AIM-HIGH trial as unexpected but possibly due to chance. “Although the number of ischemic strokes was higher in the niacin group, the overall rate was low, and we cannot be certain whether this observation reflects a causal association or possibly the statistical ‘play of chance’.”
The AIM-HIGH trial’s additional funding support was described this way in The New England Journal of Medicine: “Abbott Laboratories [maker of Niaspan] provided additional support from an unrestricted research grant. Merck donated the simvastatin [taken by all the study participants]. The companies that provided financial support or products had no role in the oversight or design of the study or in the analysis or interpretation of the data.”
You might wonder what made cardiologists so enthusiastic about niacin in the first place. A 2009 Forbes magazine article reported their reactions in response to a small clinical trial (only 208 heart patients) announced at the annual meeting of the American Heart Association. Using ultrasound in this trial funded by Abbott Laboratories, researchers showed that Niaspan was better than statins alone at clearing coronary arteries. (Niaspan, by the way, hit $254 million in annual sales in 2009. And Abbott is a “funding partner” of the American Heart Association, as noted on its website.)
Unlike the newly published AIM-HIGH trial, the statins vs. Niaspan/ultrasound trial did not look at outcomes that were meaningful to heart patients. Cleared arteries or increased HDL levels may be promising, but it is heart attack, stroke, or a heart-related early death that people are trying to avoid. The AIM-HIGH trial looked for these and other outcomes but found none; the ultrasound study did not even look at outcomes. The latter is a more common scenario.
When told to go on long-term drug or vitamin therapy, it’s a good idea ask the prescribing doctor about proven outcomes. The AIM-HIGH trial showed that raising the HDL cholesterol can only improve a lab test result. Too often doctors give their patients the impression that this is the goal. It isn’t.
Maryann Napoli, Center for Medical Consumers©
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