(dailyRx)
Heart experts at Johns Hopkins are calling premature the early end of a study by researchers at Walter Reed Army Medical Center and Washington Hospital Center on the benefits of combining extended-release niacin, a B vitamin, with cholesterol-lowering statin medications to prevent the narrowing of blood vessels.
Cardiovascular atherosclerosis, as the condition is also known, is believed responsible for one in three deaths in the U.S. each year.
The study, HDL and LDL Treatment Strategies (HALTS), involved 363 men and women and was shut down after only 208 study participants had completed the full treatment timeline of 14 months. Results showed prescribed niacin worked better in combination with a statin than another double-cholesterol-lowering drug combo, ezetimibe (Zetia) and a statin, in reducing carotid arterial wall thickness in the neck, the measure used as a gauge of atherosclerosis. An average wall reduction of 0.014 of a millimeter with niacin was observed. By contrast, the ezetimibe group showed no significant change.
Study participants, of whom nearly half were taking niacin and the rest were taking ezetimibe, were at high risk of heart disease or already had it; the average bad (low-density lipoprotein, or LDL) blood cholesterol level was 82 mg/dl. All participants had already been prescribed statin therapy.
Results in both groups showed improvements in LDL levels, which dropped by an average 18 mg/dl in the ezetimibe group, and by an average of 10 mg/dl in the niacin group. But only the niacin group showed a significant increase in good (high-density lipoprotein, or HDL) blood cholesterol levels: The average was 8 mg/dl, whereas the ezetimibe group dropped an average 3 mg/dl.
Citing the apparent benefits of niacin therapy when combined with a statin, the researchers halted the study last month.
In an editorial to be published alongside the study in The New England Journal of Medicine and presented jointly at a news conference at the American Heart Association’s annual Scientific Sessions in Orlando, Hopkins cardiologist Roger Blumenthal, M.D., says that the HALTS study has “too many limitations” for other physicians, at this time, to change the way they treat high-risk patients.
“Although study results are provocative, I am not convinced,” says Blumenthal. “These early results offer no conclusive evidence that niacin along with a statin will actually lower the number of deaths and incidents of heart attack from coronary artery disease down the road.”
Among the key study limitations, he says, are that 40 percent of study participants were not monitored for the full study duration and were left out of the final analysis.
Measuring the thickness of the inner, or intima, layer of the carotid artery, in the main blood vessel in the neck, Blumenthal adds, may not be the best predictor of actual atherosclerosis. He points out that newer techniques for measuring actual unstable plaque volume or area are considered more reliable models. Also, changes in the carotid artery may not be directly tied to changes in other arteries.
Blumenthal says observed reductions in cholesterol levels were “not that surprising” in light of other, larger studies that showed combination therapy was more effective at reaching reduced-cholesterol targets than statins alone. But stronger doses of statins might have achieved the same result, he adds, noting the HALTS study average starting LDL levels did not even meet accepted goals of less than 70 mg/dl.
The latest study results are not sufficient to merit a change in current treatment guidelines, he says, for people with coronary artery disease, namely, recommending statin therapy alone as a first step in treatment. And if statin therapy does not help patients reach their target cholesterol levels, “only then should add-on therapy, such as niacin be considered.” However, the HALTS study along with a recently published study from Oxford University supports the add-on use of niacin “as a preferred second, cholesterol-lowering agent.”
Coeditorial author and cardiologist Erin Michos, M.D., M.H.S., also at Hopkins, says that several large, ongoing international studies on the long-term vascular benefits of niacin and ezetimibe–in particular studies called AIM-HIGH and IMPROVE-IT–should provide more definitive data about whether these drugs lower rates of heart attack and stroke when used with a statin, or if statin therapy works better alone. Hopkins is participating in that research, as well.
Indeed, Michos says, preliminary results from another Johns Hopkins study, also being presented at the Scientific Sessions, show that niacin does not help reduce the volume buildup of plaque inside the arterial wall in people taking statin therapy who already had higher HDL levels. “Further research is needed still, as we have a lot to find out about the real and long-term effects of niacin on the heart and arterial blockages, she says.
She points out that extended-release niacin used in this study is a prescription medication and that it is not sold over the counter like many other vitamin B products.
Michos says the study results, regardless, do not change the fundamental basics of preventing coronary heart disease in the first place. She advocates that people stick with the everyday healthy lifestyle choices, known as the A, B, C, D, E and Fs:
- Taking antiplatelet drug therapy, such as taking daily aspirin if they are at high risk)
- Monitoring blood pressure and cholesterol levels and taking drugs as needed to control them
- Ceasing to smoke, or never smoking in the first place
- Watching one’s diet to avoid weight gain
- Exercising regularly
- Knowing one’s family history for developing such potentially fatal heart disease
Contact:
David March
410-955-1534
[email protected]