It was a day of unexpected findings for the field of cardiology. First, there was the news that patients with stents did not have a longer life span or a reduced number of heart attacks compared to patients treated with statins and other heart drugs. (Only a few years ago, drug-coated stents were being hailed as an important advance for patients with heart disease.) Then came news that a new Pfizer drug designed to raise levels of so-called good cholesterol did not reduce the amount of plaque build up in arteries. (This result complicates the presumed causal relationship between levels of HDL and arterial plaque.) And if that weren't enough, there was also more evidence that the health of circulatory system is inseparable from the health of your gums:
The researchers randomly assigned 120 people with severe gum disease and no other chronic infections to ordinary care or intensive periodontal treatment. Then they measured blood vessel elasticity, a test of blood flow efficiency, at one, two and six months afterward.
At first, the blood flow efficiency declined in the periodontal group. But it improved significantly compared with the other group when tested two and six months later.
These surprising results underscore the usual moral of scientific and medical progress: we know much less than we think we do. The future is full of facts that will falsify even the most cherished hypotheses. Buffeted by such uncertainty, the best thing we can do is put on our skeptical hats and take a few generic aspirin*:
Women who take aspirin in low or moderate doses reduce their risk of dying from any cause, particularly heart disease, a study published yesterday concluded.
Women in the study who took 1 to 14 aspirin tablets a week reduced their risk of dying from heart disease by 38 percent and by 25 percent from all causes.
*Of course, this study contradicts an earlier study which found that aspirin did not prevent heart disease. Go figure.
The more medical journal papers I read, the less surprised I am by 'surprising' findings (according to the media). The majority of studies use flawed methods and statistics, which is accepted in the medical field because of the difficulty of doing proper manipulations and controls in humans. Of course I understand some limitations are just there and there isn't much we can do about them, but there are also fixable flaws in many of these papers.
The bottom line is that the data must be taken with a large brick of salt, because as you say, over time studies tend to contradict one another, due to these necessary and unnecessary methodological flaws Just because a study is more recent, doesn't make it right.
The future is full of facts that will falsify even the most cherished hypotheses.
Sounds like someone's been reading John Ioannidis' papers.
I put up a great NIH grand rounds of his up at my site. It's really one of the best talks I've ever seen given, and I'm guessing based on that statement you'll love it.
The lack of benefit of stents refers to the COURAGE trial. Some of the criticisms on the COURAGE trial are that it did not use drug eluting stents and there was a 32.6% cross over from one group to another.