Statistics is hard, often counterintuitive, and burdened with esoteric mathematical equations. Statistics classes can be boring and demanding; students might be tempted to call it “Sadistics.” Good statistics are essential to good research; unfortunately many scientists and even some statisticians are doing statistics wrong. Statistician Alex Reinhart has written a helpful book, Statistics Done Wrong: The Woefully Complete Guide, that every researcher and everyone who reads research would benefit from reading. The book contains a few graphs but is blissfully equation-free. It doesn’t teach how to calculate anything; it explains blunders in recent research and how to avoid them.
Inadequate education and self-deception
Most of us have little or no formal education in statistics and have picked up some knowledge in a haphazard fashion as we went along. Reinhart offers some discouraging facts. He says a doctor who takes one introductory statistics course would only be able to understand about a fifth of the articles in The New England Journal of Medicine. On a test of statistical methods commonly used in medicine, medical residents averaged less than 50% correct, medical school faculty averaged less than 75% correct, and even the experts who designed the study goofed: one question offered only a choice of four incorrect definitions.
There are plenty of examples of people deliberately lying with statistics, but that’s not what this book is about. It is about researchers who have fooled themselves by making errors they didn’t realize they were making. He cites Hanlon’s razor: “never attribute to malice that which is adequately explained by incompetence.” He says even conclusions based on properly done statistics can’t always be trusted, because it is trivially easy to “torture the data until it confesses.” (more…)
In rosuvastatin should we trust?
People love the idea of preventive medicine. Preventing a disease, before it occurs, seems intuitively obvious. But when it comes to taking medicine to prevent a disease before it occurs, people tend to be much less comfortable. Not only are there the concerns about the “medicalization” of healthy people, there are good questions about benefits, risks, and costs. Cardiovascular disease will kill many of us, so there’s been decades of research studying how to prevent that first heart attack or stroke. But even if you’re born with good genes and do everything possible to prevent heart disease (e.g., don’t smoke, exercise regularly, eat a healthy diet, moderate your alcohol, and keep your weight down) you’re still at risk of heart disease. And if you have one or more risk factors for disease, your lifetime risk goes up dramatically. Once you’ve had your first heart attack or stroke, the effectiveness of medical therapy is clear. Drug therapy with medication like the “statins” class of cholesterol-lowering drugs reduces deaths from cardiovascular disease. Given their unambiguous effectiveness, and the high likelihood that many of us will eventually have cardiovascular disease of some sort, the idea of “pre-treating” otherwise-healthy people with drug therapy to possibly prevent that first event has been held out as a potential public health strategy. There’s new evidence that tests this hypothesis, and the results are surprising. (more…)
A recent article in The New England Journal of Medicine by Andrew L. Mammen, MD, PhD, reviewed statin-associated myopathies. Reading his article prompted me to revisit the subject of statin side effects.
It can no longer be disputed that statins statistically benefit patients who have cardiovascular disease or who are at high risk of cardiovascular disease. But there are still disputable issues. Which patients should be treated? The recent treatment guidelines have been widely criticized. And the actual magnitude of the benefit is small, although we know the benefits are greater for patients at higher risk. It has been argued that as many as 99% of patients who take statins will take them unnecessarily, risking side effects for no benefit. The problem is that we can’t identify which patients those are. Until we learn more, we are stuck treating the many to help the few. As with any medication, there are risks to be balanced against the benefits. What do we really know about the side effects of statins?
Lots of anecdotes, conflicting evidence
It’s very hard to pin down the truth. The Internet is full of anecdotal reports of devastating side effects from statin drugs, including cancer, dizziness, depression, anemia, acidosis, pancreatitis, cataracts, heart failure, hunger, nausea, sleep problems, memory loss, ringing in the ears, “a sense of detachment,”… the list goes on. When symptoms such as these have been evaluated in controlled studies, they have not been shown to occur more often with the drug than with placebo.
Image courtesy of www.kevinmd.com
The evidence is clear: statin drugs are effective in reducing the rate of heart attacks and death in people who have already had a heart attack as well as in people who are at high risk of having one. Some people refuse to believe that evidence; they are statin deniers, similar to the climate change deniers and AIDS deniers (and there are even germ theory deniers!) who manage to disregard the strong evidence that proves their opinions wrong. The deniers demonize statins, cherry-picking studies to minimize the benefits and exaggerate the side effects.
A new study found that negative media reports about statins were correlated with patients discontinuing statin therapy. It also found that discontinuing statin therapy was correlated with an increase in heart attacks and death.
Increasingly people are accessing healthcare information in order to make decisions for their own health. A 2010 Pew poll found that 80% of internet users will do so for health care information. This presents a huge potential benefit, but also a significant risk.
Daniel Levitin talks about the need for public information literacy, something we also discuss frequently here on SBM. If you are accessing the internet to inform your health care decisions, then you need to know how to determine the legitimacy and trustworthiness of the websites you are visiting. There is a big difference between NaturalNews (a crank site full of misinformation and conspiracy theories) and Nature News (an outlet for one of the most prestigious science journals in the world).
Even when you can discriminate between good and bad health information websites, the challenge remains to properly interpret the scientific information to which you now have access.
The statin hypothesis is that statins reduce cardiac risk more than can be explained by the reduction in LDL cholesterol. That hypothesis has been overturned by a new study.
The consensus of mainstream medicine is that a high blood level of LDL cholesterol is a major risk factor for cardiovascular disease and that lowering high levels can help with prevention and treatment. Statins have been proven effective for lowering cholesterol levels and for decreasing cardiovascular and all-cause mortality. I recently wrote about the new guidelines for statin therapy.
Currently half of American men between the ages of 65 and 74 are taking statins, and 71 percent of adults with heart disease and 54 percent of adults with high cholesterol take a cholesterol-lowering drug.
There is still a fringe group of a few maverick “cholesterol skeptics” who think lowering cholesterol is useless or counterproductive, but the evidence shows they are wrong.
We (the authors and editors) at SBM get accused of many nefarious things. Because we deliberately engage with the public over controversial medical questions, we expect nothing less. It goes with the territory. In fact, if there were a lack of critical pushback we would worry that we were not doing our job.
Still, it is disconcerting to see the frequently-repeated ideological accusations in response to simply evaluating and reporting the evidence. That is what we do here – follow the science and evidence. When that trail leads to a conclusion that some people do not like (usually for ideological reasons) a common response is to accuse us of ideology, malfeasance, being part of a conspiracy, or having conflicts of interest or ulterior motives. That is easier, I suppose, than engaging with us on the science.
One common accusation is that we are shills for the pharmaceutical industry, and downplay or ignore the benefits of diet and “natural” treatments. A search through the SBM archives demonstrates that this accusation is false – we criticize bad science and poor-quality control, regardless of who is committing it. Sometimes pseudoscience is used to promote a drug, sometimes a nutritional supplement, and sometimes pure magic. (more…)
On November 15, the American College of Cardiology and the American Heart Association released an updated guideline for the use of statins to prevent and treat atherosclerotic cardiovascular disease (ASCVD). The full report is available online. It has already generated a lot of controversy. The news media have characterized it as a “huge departure” from previous practice and have trumpeted that it will lead doctors to prescribe statins to millions more people. As usual, the truth is much more nuanced. There are some problems with the guidelines, but on the whole they represent an improved, more rational approach to prescribing statins.
Statins have always been a source of controversy: people seem to either love them or hate them, and discussions about them generate a lot of emotion. The International Network of Cholesterol Skeptics denies that cholesterol has anything to do with cardiovascular disease. An article on HuffPo calls statins “an unsafe, unnecessary product that will now be recommended to healthy people to make them sicker.” Mercola says they can actually make heart disease worse and cause premature aging, and no one should take them unless they have the genetic defect of familial hypercholesterolemia. A website collects patient self-reports of adverse effects; but like the vaccine reports on VAERS, these are only anecdotal reports of correlation, not evidence for causation.
At one time the evidence only supported using statins for secondary prevention and for men. We now have better evidence showing that they are effective for both primary and secondary prevention in patients of both sexes and all ages, and that they are more effective for those with higher risk factors. (more…)
While much of CAM is ridiculous or implausible, herbal remedies are an exception. Plants produce pharmacologically active substances; in fact, the science of pharmacology grew out of herbalism. Some herbal remedies have not been scientifically tested, but others have been tested and are clearly effective. Nevertheless, these are seldom if ever the best choice for treatment.
One natural remedy stands out. Red yeast rice has been tested and has been shown to lower cholesterol as well as a statin drug. That’s hardly surprising when you realize that it contains the exact same ingredient as the pharmaceutical drug lovastatin.
Only it doesn’t any more.
In writing about science-based medicine, we give a lot of attention to medicine that is not based on good science. We use bad examples to show why science is important and how it is frequently misapplied, misinterpreted, misreported, or even wholly rejected. It’s a pleasure, for a change, to write about a straightforward example of the best of science-based medicine in action. The book Heart 411 is such an example.
The medical literature is a jungle of conflicting and complicated studies. It’s difficult for novices and even for sophisticated non-specialists to navigate. It’s useful to have experts as guides who can apply their knowledge, experience, and judgment to analyze the data and put everything into perspective. I can’t imagine anyone more qualified as guides to “matters of the heart” than the authors of this book. Heart surgeon Marc Gillinov and cardiologist Steven Nissen practice at the Cleveland Clinic, which has been ranked as the number one heart hospital by U.S. News & World Report for the last 15 years and is currently ranked 4th best hospital overall. They have treated more than 10,000 heart patients over 30 years of clinical practice and have also done extensive research and published hundreds of articles in peer reviewed journals. Their book contains everything they would like their patients to know about the prevention, diagnosis, and treatment of heart disease. It amounts to an owner’s manual for the heart. (more…)