Trick or Treatment—The Undeniable Facts about Alternative Medicine (Electronic book text)

First, the trial was carefully controlled, which means that the separate groups of patients were treated similarly except for one particular factor, namely bloodletting. This allowed Hamilton to isolate the impact of bloodletting. Had the bloodletting group been kept in poorer conditions or given a different diet, then the higher death rate could have been attributed to environment or nutrition, but Hamilton had ensured that all the groups received the ‘same care’ and ‘same comforts’. Therefore bloodletting alone could be identified as being responsible for the higher death rate in the third group.

Second, Hamilton had tried to ensure that his trial was fair by guaranteeing that the groups that were being studied were on average as similar as possible. He achieved this by avoiding any systematic assignment of patients, such as deliberately steering elderly soldiers towards the bloodletting group, which would have biased the trial against bloodletting. Instead, Hamilton assigned patients to each group ‘alternately’ and ‘indiscriminately’, which today is known as randomizing the allocation of treatments in a trial. If the patients are randomly assigned to groups, then it can be assumed that the groups will be broadly similar in terms of any factor, such as age, income, gender or the severity of the illness, which might affect a patient’s outcome. Randomization even allows for unknown factors to be balanced equally across the groups. Fairness through randomization is particularly effective if the initial pool of participants is large. In this case, the number of participants (366 patients) was impressively large. Today medical researchers call this a randomized controlled trial (or RCT) or a randomized clinical trial, and it is considered the gold standard for putting therapies to the test.

Although Hamilton succeeded in conducting the first randomized clinical trial on the effects of bloodletting, he failed to publish his results. In fact, we know of Hamilton’s research only because his documents were rediscovered in 1987 among papers hidden in a trunk lodged with the Royal College of Physicians in Edinburgh. Failure to publish is a serious dereliction of duty for any medical researcher, because publication has two important consequences. First, it en courages others to replicate the research, which might either reveal errors in the original research or confirm the result. Second, publication is the best way to disseminate new research, so that others can apply what has been learned.

Lack of publication meant that Hamilton’s bloodletting trial had no impact on the widespread enthusiasm for the practice. Instead, it would take a few more years before other medical pioneers, such as the French doctor Pierre Louis, would conduct their own trials and confirm Hamilton’s conclusion. These results, which were properly published and disseminated, repeatedly showed that bloodletting was not a lifesaver, but rather it was a potential killer. In light of these findings, it seems highly likely that bloodletting was largely responsible for the death of George Washington.

Unfortunately, because these anti-bloodletting conclusions were contrary to the prevailing view, many doctors struggled to accept them and even tried their best to undermine them. For example, when Pierre Louis published the results of his trials in 1828, many doctors dismissed his negative conclusion about bloodletting precisely because it was based on the data gathered by analysing large numbers of patients. They slated his so-called ‘numerical method’ because they were more interested in treating the individual patient lying in front of them than in what might happen to a large sample of patients. Louis responded by arguing that it was impossible to know whether or not a treatment might be safe and effective for the individual patient unless it had been demonstrated to be safe and effective for a large number of patients: ‘A therapeutic agent cannot be employed with any discrimination or probability of success in a given case, unless its general efficacy, in analogous cases, has been previously ascertained…without the aid of statistics nothing like real medicine is possible.’

And when the Scottish doctor Alexander MacLean advocated the use of medical trials to test treatments while he was working in India in 1818, critics argued that it was wrong to experiment with the health of patients in this way. He responded by pointing out that avoiding trials would mean that medicine would for ever be nothing more than a collection of untested treatments, which might be wholly ineffective or dangerous. He described medicine practised without any evidence as ‘a continued series of experiments upon the lives of our fellow creatures.’