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The Enigma of “Evidence-Based Medicine”

It is hard to imagine, but the practice of medicine was not always evidence-based. We have Archie Cochrane, the man behind the "Cochrane Review", to thank for that.

I know what you’re thinking. If not evidence-based, what else could medicine be? Well, it could be based on conjecture, hearsay, wishful thinking, anecdote or just plain flim-flam. Indeed, throughout most of our history, medicine was not evidence-based. Bloodletting, purging and various herbal treatments were practiced without any attempt to systematically determine whether they worked. Heart attack victims were put on extended bed rest, and patients after cataract surgery had to endure days of lying still with sandbags over their heads, just because this seemed logical. Total mastectomies for breast cancer were routine before evidence showed that a lumpectomy, coupled with adjuvant therapy, was as effective for many women as removal of the whole breast. If a baby was born by Caesarean section, recommending a section for the next birth was accepted practice. Evidence now indicates that this is not always necessary.

Today, most reasonable people would agree that any medical intervention should be based on the best evidence available, with that evidence coming from properly controlled trials. That’s how we get a grasp on what works and what does not, what is safe and what is not.

Archie Cochrane was instrumental in putting us on this track. Born and educated in Britain, he became a captain in the Royal Army Medical Corps. During the Second World War, Cochrane was taken prisoner by the Germans after a disastrous British campaign in Crete and served as a prisoner-of-war medical officer in a camp in Salonika. Conditions were miserable: typhoid, diphtheria and jaundice were rampant, food was scarce and many prisoners suffered from swollen legs, characteristic of starvation. Cochrane was overwhelmed and baffled about what to do. While he had the freedom to try any treatment he wished, he realized that there was no evidence that any of the available options had a chance of working. But something had to be done.

Cochrane’s medical hero growing up was James Lind, the Scottish physician who in 1747 ran what may have been the first-ever randomized controlled clinical trial, which showed that scurvy could be cured with citrus fruits. The active ingredient was later found to be vitamin C, which Cochrane had at his disposal in the prison hospital. He thought that the edema the prisoners experienced might be due to a vitamin deficiency, and vitamins C and B were, in his mind, reasonable candidates. Cochrane managed to purchase some yeast, which provided a source of B vitamins, on the black market and organized a trial.

Twenty young prisoners were recruited and randomly separated into two wards. One group received vitamin C each day; the other was treated with yeast. Each man’s liquid intake was measured, as was his urine production. By the fourth day, it had become evident that the yeast group was eliminating more fluid and that there was less edema. Cochrane presented his results to the German commander, who was impressed enough to order that yeast be made available to all prisoners. On reflection, Cochrane later admitted that the trial was too small, too short and the measurements of outcome—basically the number of buckets of urine produced—poor. But the experiment, one that Cochrane would refer to it as “my first, worst and most successful clinical trial,” produced an effective treatment. And after the war, it made him a champion of randomized clinical trials and a promoter of systematic reviews of such trials. Decisions about treatment, he maintained, should be based as much as possible on reviewing all the evidence from relevant trials. Well said. Today, “Cochrane Reviews” are one of the most highly respected sources of information for the practice of evidence-based medicine.


@JoeSchwarcz

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