麻豆传媒

THE strange term 鈥渆vidence-based鈥� regularly turns up in the medical journals
nowadays. It first entered the doctor鈥檚 phrase book back in the 1980s when
someone came up with the startling idea that treatments which work are better
than those which don鈥檛, and that the best way of distinguishing between them is
to look at the evidence.

You may already be scoffing, and the no-frills name鈥斺�漞vidence-based
medicine鈥濃�攊s unlikely to stop you. But selecting best-buys in healthcare
is a lot trickier than arranging Which?-style tests on washing machines
and video cameras. Yet despite this, the enterprise is making headway.

Keen to join this rising star, nurses, physiotherapists, dentists and even
health administrators are now adopting the vogue for self-scrutiny. One group,
though, seems to be foundering in its attempt to show it gives value for money:
the health promoters, whose job it is, largely at public expense, to nag us into
living more healthily. Their search for evidence reveals an embarrassing gap
between aspirations and achievements.

Finding out if people can be persuaded to live healthier lives relies on the
methods used to test drugs. You give one lot the treatment, then look for
improvements in that group compared to another lot who haven鈥檛 had it. Heart
disease is an important killer, linked to a string of avoidable risks from
cigarettes to hamburgers, so it has always been a key target for health
promotion鈥檚 self-appointed tribunes. Trying to prevent it has also been one of
the biggest flops.

A 1970s American classic of this genre was titled the Multiple Risk Factor
Intervention Trial (or 鈥淢r Fit鈥濃�攐ne of the early acronymic jokes beloved
of trial organisers). The impenetrable name can be explained in this way: 鈥渞isk
factors鈥� are things like smoking, which predispose you to heart disease; the
fact that there are several of them gives us the term 鈥渕ultiple鈥�; and
鈥渋ntervention鈥� is included because the object of the study was to change
peoples鈥� habits. Having spent around $100 million cajoling their target
group to live more healthily, the researchers were able to claim they鈥檇
prevented perhaps a dozen deaths. Hardly value for money.

To explain this failure, the group said that while the people they had worked
on were leading healthier lives, so were those on whom they had lavished no
extra attention. Because of the publicity about heart disease in the American
media at that time, everyone had been changing their habits. So the experiment
had been ruined鈥攊n one sense at least.

This was possibly true, although after so much expenditure of money and
effort, it did sound rather feeble. Still, if nothing else, lessons would have
been learnt. Or would they? Not in Wales, apparently. Undeterred by
transatlantic failure, 1985 saw the launch of a Welsh campaign to reduce heart
disease. Winsomely titled 鈥淗eartbeat Wales鈥�, the project published its final
results this year in the British Medical Journal (vol 316, p 818). In a
painfully honest analysis of their efforts, director Chris Tudor-Smith and
colleagues admitted that 鈥渘o definite conclusions can be drawn concerning the
efficacy of the Heartbeat Wales programme鈥︹�� That sentence must have caused
anguish to those who wrote it, but sympathy diminishes as you read on. Far from
conceding that no one has yet fathomed out how to persuade anyone to live more
healthily, the group writes of the need to develop 鈥渘ew evaluation
techniques鈥濃�攄esigned, presumably, to show they were doing the right
things, even though they couldn鈥檛 prove it.

Last year, Shah Ebrahim and George Davey Smith鈥攖wo of Britain鈥檚 more
sceptical epidemiologists鈥攔eviewed 14 attempts of this kind to reduce
heart disease (BMJ, vol 314, p 1666). They concluded that these
packages of advice and education were failing to prevent deaths due to heart
disease, or anything else for that matter. Alas, their findings appeared too
late to deter Heartbeat Wales鈥� organisers.

In my youth I was a smoker鈥�30 to 40 on a bad day. I knew all the risks.
The only effect of the anti-smoking adverts at the cinema was to remind me to
light up, if I hadn鈥檛 already. Providing health information to those who want it
is a valuable service. But until we understand how to change people鈥檚 behaviour,
replicating the same expensive failures again and again is futile and
wasteful.