Despite the invention of the clinical trial and regardless of the evidence against bloodletting, many European doctors continued to bleed their patients, so much so that France had to import 42 million leeches in 1833. But as each decade passed, rationality began to take hold among doctors, trials became more common, and dangerous and useless therapies such as bloodletting began to decline.
Prior to the clinical trial, a doctor decided his treatment for a particular patient by relying on his own prejudices, or on what he had been taught by his peers, or on his misremembered experiences of dealing with a handful of patients with a similar condition. After the advent of the clinical trial, doctors could choose their treatment for a single patient by examining the evidence from several trials, perhaps involving thousands of patients. There was still no guarantee that a treatment that had succeeded during a set of trials would cure a particular patient, but any doctor who adopted this approach was giving his patient the best possible chance of recovery.
Lind’s invention of the clinical trial had triggered a gradual revolution that gained momentum during the course of the nineteenth century. It transformed medicine from a dangerous lottery in the eighteenth century into a rational discipline in the twentieth century. The clinical trial helped give birth to modern medicine, which has enabled us to live longer, healthier, happier lives.
Evidence-based medicine
Because clinical trials are an important factor in determining the best treatments for patients, they have a central role within a movement known as
Evidence-based medicine empowers doctors by providing them with the most reliable information, and therefore it benefits patients by increasing the likelihood that they will receive the most appropriate treatment. From a twenty-first-century perspective, it seems obvious that medical decisions should be based on evidence, typically from randomized clinical trials, but the emergence of evidence-based medicine marks a turning point in the history of medicine.
Prior to the development of evidence-based medicine, doctors were spectacularly ineffective. Those patients who recovered from disease were usually successful despite the treatments they had received, not because of them. But once the medical establishment had adopted such simple ideas as the clinical trial, then progress became swift. Today the clinical trial is routine in the development of new treatments and medical experts agree that evidence-based medicine is the key to effective healthcare.
However, people outside the medical establishment sometimes find the concept of evidence-based medicine cold, confusing and intimidating. If you have any sympathy with this point of view, then, once again, it is worth remembering what the world was like before the advent of the clinical trial and evidence-based medicine: doctors were oblivious to the harm they caused by bleeding millions of people, indeed killing many of them, including George Washington. These doctors were not stupid or evil; they merely lacked the knowledge that emerges when medical trials flourish.
Recall Benjamin Rush, for example, the prolific bleeder who sued for libel and won his case on the day that Washington died. He was a brilliant, well-educated man and a compassionate one, who was responsible for recognizing addiction as a medical condition and realizing that alcoholics lose the capacity to control their drinking behaviour. He was also an advocate for women’s rights, fought to abolish slavery and campaigned against capital punishment. However, this combination of intelligence and decency was not enough to stop him from killing hundreds of patients by bleeding them to death, and encouraging many of his students to do exactly the same.