Saturday, 2 June 2007

Follies and fantasies in medicine

Petr Skrabanek

This is a great book, recommend you at least to read final chapter.
He demolishes many shibboleths of modern medical practice, in fact it is different only in a matter of degree from faith healing. Medicine is not science, it is an art of diagnosis resting on authority. The royal college of physicians quoting Popper is only so much rhetoric.

What's worse, while there is of good science - true science - there's also a lot of bad science related to human nature and scientific publishing.
What happens is that a correlation is considered statistically significant - rather arbitarily inthe scientific community - if there is only a five percent chance it could have happened by chance. But medical science there are an enormous number of potential causations and a large number of hypotheses tested by researchers; given the large number there will be false positives showing ineffective interventions, informative predictors, risk factors, or association - connections that do not fact exist. It may be that these studies have been replicated, but because they are show negative results they are never put forward for refereeing to the science journals: a bias towards tabloid journalism, even here.
For personal or career reasons, who wants either to replicate someone's positive - no prestige for being second - or, only slightly better, refute it. And so you have all these "links" between chocolate eating and cancer, mobile phones and brain tumours etc etc.

The difficulties arise when bad science meets the scientifically untrained doctor. A true scientist is humble. His subject is always subject to revision. He is a sceptic.
Many medical researchers are not as sceptical as they should be.
And the house doctor the least of all: not even necessarily trained in scientific method, at med school, even though he acquired a lot of scientifically-based knowledge.
Instead the doctor is a member of the new clerisy, a dispenser of authoritative gospel based on what many common people think is the new infallible dogma. This gives the doctor great power. He is not a searcher of wisdom or truth. He is an authority on providing solutions.


Some solutions work better than others. It will depend on a number of less than scientific factors. His solution is modified by personal events - a diagnosis that worked spectacularly on one rare disease in his youth which foxed others and which earnt him some approval he will continually reapply even though this may be inappropriate for new situations. It will depend on the nice dinner he received from the drugs companies, who educated him in one diagnosis that – surprise – will be cured by their drug. On the good science but sometimes the bad science he has read in the medical journals. Above all, perhaps, from the body of clinical medicine learnt from med school and which contains a surprising number of received wisdoms that haven’t sufficiently been put on trial.

An example of how follows habit, custom, received wisdom is on the issue of high blood pressure, which affects 70 per cent of the Western world’s population over fifty. Becuase it "above acerage" the reponse is that it has to be cured.
But in fact there have been studies – good, if unheeded science ths time - that show that while very high diastolic blood pressure is advisedly treated, low hypersensivity treated with diuretics such as propranolol shows no benefit in reduction in mortality while causing a whole host of other side effects, such as gout, diabetes and impotence. Those who took placebo tablets did not escape side effects, suggesting that attaching the label hypertensive has, in itself, deleterious consequences. Many people take medicines against high blood pressure on the advice of their doctors.

The lesson is that medicine, even today, is not a monolithic subject, but a mixture of more or less sound practices. Some medicine is excellent science, other bits of medicine the consequence of poor or untested scientific method; and the application of these are at the whims of a doctor whose human nature plays an important part. Doctors are not scientists or scientific thinkers who assess evidence, but people of broad scientific and medical education who apply what they know to the best of their ability and put their considerable authority behind it.
Is this authority essential to their job, since the comforting consultation has a genuine placebo effect, or are patients best served if the chaos that happens off stage - scientific process - is made public?
There's a lot of food for thought in this book, and one possible article I would like to write is how the author, Petr Skrabanek, a Czech, a Lancet leader writer and academic, had his reputation posthumously blackened by the medical establishment for his alleged links with the smoking companies. The heretic, like his countryman Jan Huus, the first protestant, burnt at the stake.