UPDATED: 02:42 GMT, 6 July 2010
Have you been left confused by expert health advice? Even people like me, with years of experience in science and medical journalism, are left scratching our heads when research is contradicted by other studies or turns out to be wrong.
In early 2008, new
guidelines for life-saving emergency heart attack treatment said you should no
longer bother with the 'mouth-to-mouth' part of CPR (cardiopulmonary
resuscitation). Instead, you should pump the chest non-stop.
Having got my Red Cross
certificate some years ago, I wanted to know more - but discovered that while
this change was endorsed by the European Resuscitation Council, the Red Cross
still trains people to give mouth-to-mouth.
So I asked Paul Schwerdt, a cardiac resuscitation expert who restarts hearts daily. He told me to forget about CPR, because even trained laypeople rarely do it well enough to make a difference.
He said the best thing is
an Automated External Defibrillator - a portable, easy-to-use device that is
increasingly available in public places.
I found an article that
said it can raise the survival rate for people having heart attacks outside
hospital from 1 per cent to 80 per cent. But then I read another study saying
such devices don't increase survival compared with CPR.
Little wonder that
'expert' health research leaves many of us confused - and that includes medics,
too.
John Ioannidis, a doctor
specialising in infectious diseases who is also a medical research analyst, has
looked at hundreds of studies and discovered that two in every three
conclusions published in medical journals are later found to be wrong.
The problem is that those
are the sorts of conclusion your doctor reads when deciding if it makes sense
to prescribe an antibiotic for your child's ear infection, or if the benefits
outweigh the risks in suggesting that middle-aged men take a small daily dose
of aspirin.
The two-out-of-three
wrongness rate Professor Ioannidis found could be worse: he examined only the
less than one- tenth of 1 per cent of research that makes it to prestigious
journals. So, what is going on?
Here
are some of the reasons why experts get it so wrong:
RESEARCHERS
MAKE UP FINDINGS
The research community
likes to say that the high-profile cases of fraud we see in the media - such as
the South Korean researcher Woo Suk Hwang's fake claims to have cloned human
stem cells in 2005 - are rare events.
Another notorious example
was that of the cancer researcher William Summerlin, who won praise for
achieving skin grafts on genetically incompatible black and white mice.
In fact, he had used a
marker pen to blacken patches of fur on white mice. But research fraud appears
to be rife.
In an anonymous survey of
3,200 medical researchers in the journal Nature, a third confessed to at least
one fraudulent act or 'massaging' research results.
In a similar survey, half
the research workers said they knew of studies that involved fraud.
The proportion that are
caught is minuscule. What motivates such surprising levels of dishonesty?
The answer is simple:
researchers need to keep on publishing impressive findings in scientific
journals in order to keep their professional careers alive, and some seem
unable to come up with them through honest work.
THEY FIDDLE THE RESULTS
Highly respected
scientists toss out data all the time. They pretty much have to. It would be
hard to justify keeping 'findings' when a key piece of equipment is faulty or
if patients in studies are caught not sticking to their drug or diet regimens.
The problem is that it's
not always clear where to draw the line between data that is bad and data that
the researcher just doesn't like. Douglas Altman, who
directs the Centre for Statistics in Medicine in Oxford, examined more than 100
drug studies, comparing raw data and published results. He found that in most
studies some data was left out - and more often than not it didn't fit the conclusions
and might raise difficult questions.
The ultimate form of data
cleansing is throwing away a whole study's worth of information by not
submitting it for publication because the results aren't the ones hoped for. Often, these 'lost'
negative results are from studies funded by drug companies - if you are trying
to get a medicine onto the market, you don't want to publish research that
makes it look bad. A study two years ago
revealed that 23 out of 74 antidepressant trials were not published. All but one had found the
drugs to be more or less ineffective compared with a sugar pill placebo. In contrast, all 37
positive studies were published.
THEY STUDY THE WRONG
PATIENTS
The reason trials may
prove untrustworthy is because they study the wrong people. A study might be
virtuous about its results, except it was assessing a drug's effects on the
wrong people - those who do not represent the patients who would need the drug.
Sometimes people in
medical studies are particularly health conscious or unusually ill. Then there
is the fact that many studies pay you to take part, which results in a high
percentages of poor people, and sometimes alcoholics, drug misusers and the
homeless. These sway the results.
Studies in the Nineties
appeared to prove hormone replacement therapy (HRT) reduced the risk of heart
disease by 50 per cent. Then a large study in 2002 seemed to prove HRT
increased the heart disease risk by 29 per cent. Why the huge discrepancy?
It turned out the groups had significantly different balances of people: the
first had relatively young women, the second older women, leading both to
produce misleading results.
THEY MOVE THE GOALPOSTS
Sheer chance means that in
a medical or psychological study, you will always see improvement in a group of
people over time - a slight loss in excess weight, for instance.
That change needn't have
anything to do with what is being tested, but the researcher can then claim it
was due to whatever was being tested by writing up the study as if that change
was what was being tested for.
'It's like throwing darts
on a wall and then drawing a dartboard around them,' says Douglas Altman.
He has compared study
proposals submitted by researchers with the published findings: 'We found the
stated focus of research was different in more than half the cases.'
In other words, half the
results were flukes that had been turned into alleged scientific fact.
THEY STUDY THE WRONG
MAMMAL
In a notorious incident
four years ago at Northwick Park Hospital, Middlesex, an experimental leukaemia
drug was given to six volunteers. They all quickly fell
seriously ill. The drug had been safety-tested beforehand and passed with
flying colours. But it had been safety- tested on animals, where it had shown no
harmful effects, even at doses up to 500 times higher than those given to the
volunteers.
Health research has become
dependent on animals. Treatment breakthroughs you see in the media frequently
turn out to be based on studies of mice. But often the results don't translate
to humans.
Three-quarters of drugs
fail human trials because of dangerous side-effects or simply failing to
provide cures.
Adapted
from Wrong: Why Experts Keep Failing Us And How To Know When Not To Trust Them
by David H. Freedman (Little, Brown, £12.99). To order a copy (P&P free),
call 0845 155 0720.
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