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June 22 - June 30, 2018
We all have been, and will be, patients.
If you have followed the news about prostate cancer screening, mammography for women in their forties, hormone replacement, cholesterol-lowering medications, and stents for coronary-artery disease, you might think doctors cannot get anything straight.
flecainide, as well as a similar drug, decreased PVCs as expected but also increased patients’ chance of dying.* The
People who took losartan had fewer strokes and lived longer than those that took atenolol. At first glance it seemed that we had come up with a better antihypertensive; this seemed like an example of replacement. Somewhat surprising was that both drugs lowered blood pressure the same amount. The question was, did losartan beat atenolol because losartan is better or because atenolol is actually ineffective?
Atenolol did lower people’s blood pressure, but it did not decrease people’s risk of dying or of having a heart attack.
longer. A recent study showed that metoprolol (another beta-blocker) is no better than atenolol.
There is a long list of medical procedures whose use is based on scientific evidence that is, at best, suspect. Vertebroplasty is another great example. For years, doctors struggled to treat people (mostly women) who suffered osteoporotic fractures of the spine. These fractures can lead to chronic back pain. In the late 1990s, a couple of radiologists had a brilliant idea. Why not insert a needle into the fractured bone and inject medical-grade cement. The theory was that the cement would plump up the bone, the nerves would get some extra breathing room as the fractured bone was lifted away,
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In 2009 two groups of brave investigators put vertebroplasty to the true test. They enrolled 200 patients. Half of the patients got vertebroplasty; the other half were taken to the procedure room and prepped for the procedure; the cement was opened, so patients could smell it; and salt water was injected. Both groups of patients, those that got vertebroplasty and those that had a sham procedure, had identical improvements. Vertebroplasty, as it turned out, is no better than a placebo.
Disbelief is strongest when it comes to medical reversals that have to do with how people feel. When
Doctors often pursue treatments that improve survival while making patients miserable in the process. Patients usually have precisely the opposite goals—they value feeling better much more than living longer.
said, it does seem that the placebo effect is most common when it comes to therapies meant to reduce pain and that the effect tends to be relatively short-lived.
The objective measure of lung function was no surprise: only albuterol improved how much air patients could move. The subjective outcome results, however, were a bit of a shock. Patients reported that all three therapies were better than doing nothing and all three were equally effective.
of the reversals that we have discussed, and will discuss, occur because we have adopted therapies whose efficacy is supported by inadequate data. Surrogate end points are at the heart of a generous portion of that inadequate data.
At the end of the study, there was no difference between the groups in terms of the combined rate of death from a cardiovascular cause, heart attacks and strokes. There was one difference in outcomes between the groups: there was a clear difference between the two groups in terms of overall mortality. In one group, 4 percent of the patients died; in the other, 5 percent died. Unexpectedly, the group with a higher death rate was the intensive-treatment group.
They found that one-third of the time, when hospitalizations went down, mortality went up, or vice versa, meaning that a treatment that prevented hospitalization made you more likely to die;
have yet to see such assurance for any surrogate end point, and recent history has given us ample reason to be skeptical for the time being.
Colonoscopies are currently being tested in randomized trials, and the results should be back in the early 2020s.
This test has been shown to reduce overall death rates as well as death rates from lung cancer (goals 3 and 2, respectively). This is the only screening test to date that makes you live longer.
caveats. Most of the abnormalities that are found with this test, and thus demand evaluation, turn out to not be cancers. (In one study, 96 percent of abnormal findings were false alarms.)
all screening programs find a mix of deadly cancers and “sit and do nothing” cancers.
for prostate cancer, we end up treating around 40 cancers for every cancer that will kill.†
The best studies suggest that if a mammogram finds breast cancer, and it is treated, there is a 13 percent chance that the mammogram will have saved a life.
there is evidence that screening for prostate cancer does increase the rate of death from non–prostate cancer causes, specifically from cardiovascular death and suicide.
arms race: the Benefits of Universal Glove and Gown, or BUGG study)
There have been some major discrepancies between single-center and multiple-center (multicenter) trials.
The Hawthorne effect is a psychological principle stating that people perform differently (usually better) when they know they are being watched.
Then in 2005, the MERIT trial was conducted at 23 hospitals in Australia. The investigators randomized hospitals to either adopt the RRT model or not. They found that although the RRT was well utilized, the number of cardiac arrests, unplanned ICU admissions, and unplanned deaths did not change.
The MERIT trial demonstrated both that RRTs do not work and that we are getting better at treating these patients.
This study found that strict blood-sugar reduction actually increased deaths by 2.6 percentage points at 90 days.
10 different trials concluded that neither glucosamine, chondroitin, nor their combination improve joint pain.
In 2013, the latest and most extensive review of the randomized trials that have studied multivitamin use found no clear benefit on overall survival, heart disease, or cancer.
analyses of randomized trials find that calcium and vitamin D supplementation does not reduce the risk of fractures among healthy women.
For years we have known that calcium and vitamin D supplementation has an important adverse effect: an increase in kidney stones. In 2010 a group of researchers identified another potential side effect: heart attacks.
In 2011 the same group examined studies of vitamin D plus calcium, and again they found the risk of heart attack
If you want a sense of how rare these syndromes are now, ask your doctor to describe the symptoms of pellagra or beriberi—and prepare for an uncomfortable silence.
National Institutes of Health’s National Center for Complementary and Alternative Medicine (NCCAM). NCCAM’s website is one of our favorite places to while away a few hours.
Available evidence suggests that the lay population is even slower to abandon ineffective therapies than the medical field—in fact, we seem to be totally unaffected by negative data.
Cognitive dissonance is the psychological theory that proposes that we have difficulty making sense of information that contradicts our worldview.
You had to treat about 90 people with the diet for five years to prevent one stroke. Given the flow of this book, you probably think that we are telling you about PREDIMED because it was later contradicted. It was not. We are writing about it because it shows just how difficult it is to do a study of a diet that proves anything.
We would need such large studies, of so many combinations, over so many years, that we would run out of people to randomize.
Ioannidis considered all the highly cited papers published in key medical journals during the years 1990 to 2003. Of those, 45 found that a medical intervention was effective. He then tracked all reports of these interventions’ efficacy over the years to come. He found that seven (16 percent) were later found to be ineffective, another seven (16 percent) were found less effective than initially believed, 20 (44 percent) were supported in future studies, and 11 (24 percent) were never tested again.
The study suggested that 16 percent of the most widely cited medical literature is later contradicted.
Of the 35 studies that did examine the current standards of care, 16 (46 percent) showed that the standard of care was ineffective.
Of these, 363 articles reported the results of studies that tested the efficacy of an established practice. Reversals were found in 146 (40 percent) of these studies, 138 (38 percent) of the studies reaffirmed the benefit of the new practice, and 79 (22 percent) were inconclusive. The
“Half of what you are taught in medical school is wrong. The trouble is, we do not know which half.”
the group that had received the stents was having more strokes. After an average follow-up of one year, 20 percent of the patients in the stent group had strokes, compared with only 12 percent of those in the medicine-only group. That is an increased absolute risk of 8 percentage points, or, in news-report language, a 64 percent increase in the rate of stroke.
Medical practices, however, are like freight trains—they do not stop quickly.
They tracked citations to three major practices that were found not to work: beta-carotene to prevent cancer; estrogen to prevent Alzheimer’s disease; and vitamin E to lower cardiovascular risk. They found that 10 years passed before the research community stopped referencing the flawed practice.
The important question here, and this is really key, is whether doing something different changes the outcome. Does screening for postpartum depression really help people feel better?
Every day you hear that the stock market went up (or down) because of some report or event. If the relationship were really that predictable, would anybody lose money in the market?
