Every few years, new information emerges that fundamentally alters how doctors care for patients. Subtle improvements occur constantly. Major improvements occur less commonly. Two significant clinical trials have just been reported and should alter how doctors treat patients who have established coronary artery disease. Whether doctors will be able to do so is another question I will address in future columns.
The Heart Protection Study was reported at the recently concluded American Heart Association meeting. There has been substantial uncertainty about the long-term benefits of cholesterol-lowering drug therapy and of antioxidant vitamin supplementation for certain categories of patients with heart disease. 20,536 individuals in 69 UK hospitals were randomized in various disease categories. These included coronary disease, other occlusive arterial disease, diabetes, hypertension, women, patients over 70, and those with "low" cholesterol levels. Half received a statin and half received placebo tablets. Within each of these two groups, half received vitamins (E, C, beta-carotene) and half placebo capsules. Treatment and follow-up continued for an average of five and a half years.
The study found that cholesterol lowering with statin treatment reduces the risk of heart attacks and of strokes by at least one-third in a very wide range of high-risk patients for whom there had previously been uncertainty about using cholesterol-lowering therapy. The Heart Protection Study provides the first direct evidence that cholesterol-lowering therapy cuts the risk of heart attacks and strokes by at least one third not just in people who already have coronary disease but also in those who have diabetes, narrowing of arteries in their legs or a previous history of stroke. It shows that for high-risk patients, cholesterol-lowering therapy produces substantial benefits even among those considered to have ‘low' cholesterol levels. It also demonstrates clear evidence of benefit in women and in patients over 70. The study's size and the wide range of high-risk patients mean that doctors now have evidence that is clear and credible. Moreover, the benefits increased throughout the study treatment period so more prolonged therapy might be expected to produce even bigger benefits.
Worldwide, if an extra 10 million high-risk people worldwide go onto statin treatment, about 50,000 lives each year could be saved, or about a thousand people a week.
Additionally, the Heart Protection Study did not provide any evidence that antioxidant vitamins could prevent deaths, heart attacks, strokes or other vascular disease outcomes in any of the groups studied. This observation leads us to the next report.
The second study is a smaller, but nonetheless hugely important, report that adds interesting and potentially worrisome observations. The HDL-Atherosclerosis Study, called HATS, studied 160 men and women with clinical coronary disease and documented closure of coronary arteries. All had low HDL cholesterols, only minimally elevated bad cholesterols (LDL) and no more that moderate elevation of their triglyceride levels. They were assigned to one of four treatments, comprised of a statin, antioxidant vitamins (Vitamin E, C, beta carotene and selenium), a combination of statin plus antioxidants, or just placebos.
The patients on the combination of a statin and niacin had an astonishing 60 to 90 percent reduction in major clinical events clinical compared to the placebo group. But the effect of the supplemental antioxidants was negative, actually blunting the benefit of the statin. The reason may be related to the observation that antioxidants lower levels of the good HDL cholesterol.
Additionally, these data show that in patients who have had heart disease, statin therapy reduces further the risk of subsequent cardiovascular events, even if the bad LDL cholesterol levels are normal. This effect may be even more beneficial when combined with niacin, which further increases the good HDL cholesterol. In both of these landmark studies, antioxidant supplementation showed no benefit and perhaps even some detriment in that they seemed to blunt the benefit of the cholesterol lowering regimen.
If you are taking supplemental antioxidant vitamins to prevent heart disease, you may want to consider the accumulating objective evidence that they might not be helping. If you have had coronary disease, ask your doctor if the data from the Heart Protection Study and HATS apply to you.