I endorse and support, I believe, the principle of evidence-based medicine (“EBM”).
I do so having no medical qualifications whatsoever because the validity of the principle, I believe, transcends the practice of medicine.
Apparently it is claimed that EBM is relatively new. Initially, that’s a surprise. It dates from, it appears, about 1996. While still supporting its practitioners I doubt this claim. It claims too much. It seeks to appropriate the word evidence to apply only to some evidence and not to other evidence. Did the medical profession not act on evidence before 1996?
I think it did.
The practice of bloodletting lasted for at least 2,000 years with no proven benefit to the modern mind. This did not mean it could not be justified. The justification lay in the acceptance of the theory of the four humours.
According to the theory, a human person was, in effect, constituted of a mixture of the four humours. Bloodletting was calculated to affect the balance of these humours. The effect of these humours, black bile, yellow bile, phlegm and blood extended to the explanation of character.
Those with too much blood were sanguine. Those with too much phlegm were phlegmatic. Those with too much yellow bile were choleric, and those with too much black bile were melancholic. To be sanguine is to be courageous, hopeful and amorous. To be phlegmatic is to be calm and unemotional. To be melancholic is to be depressed, sleepless and irritable. To be choleric is to be easily angered and bad tempered.
It is relatively easy to find living examples of these types and, having done so, to think that that discovery is supportive evidence of the theory of the four humours.
The alternative theory, that of EBM, is to follow the scientific method.
Based on observations of a phenomenon, a scientist may generate a model. This is an attempt to describe or depict the phenomenon in terms of a logical physical or mathematical representation. As empirical evidence is gathered, a scientist can suggest a hypothesis to explain the phenomenon. This description can be used to make predictions that are testable by experiment or observation using the scientific method. When a hypothesis proves unsatisfactory, it is either modified or discarded.”
The significant word is “hypothesis”. The quote suggests that the hypothesis follows the gathering of evidence. This is not likely. The hypothesis, or its predecessor (another hypothesis) must precede the gathering of evidence. This is true even when the evidence presents itself to us almost complete, say, when a body is discovered with a knife sticking out of its back. We have already formed the view that such circumstances are more consistent with murder or manslaughter than with suicide or accident.
The “scientific method” is not new. Eratosthenes applied it to the measurement of the circumference of the Earth in 240 BC. He learned of a well at Syene in southern Egypt, where the sun, on the summer solstice, shone directly down into the well. At Alexandria in northern Egypt, on the solstice, the sun was not overhead; it was at an angle of seven degrees 12 minutes. He estimated the distance from Alexandria to Syene and concluded that that distance represented one fiftieth of the circumference of the Earth, because the angle of the sun in Alexandria on the solstice was one fiftieth of a circle. Of course, he also concluded that the Earth was circular in shape.
The quality of the hypothesis is critical. So, too, is the ability to collect evidence.
Generally the Minister for Health and Children expounds a hypothesis to explain health care infections. These are infections contracted almost exclusively in places such as hospitals and nursing homes. The Minister’s theory focuses on the supposed natural history of the pathogens involved. It resolutely assumes that the first and principal defence of humanity from pathogens is antibiotic use and that that defence has been breached. We know this because, in the context of addressing health care infections, she castigates the medical profession for over-prescribing antibiotics in the past. Sometimes this idea is elided into the idea that it is consumption of antibiotics that is the problem and by implication that the patients are responsible.
She does endorse other ideas but, in doing so, implies that the general public, like the medical profession, are implicated in the chain of causation through visiting patients in hospitals.
What is revealing is her own admission that you can only manage what you measure.
It was only in March 2008 that she made Clostridium difficile a notifiable disease.
This was the only method of determining the incidence of this dangerous, often fatal, disease.
This proposition was the subject of a post HERE in 2007.
EBM is of little use as an idea if it is not preceded by the appropriate hypothesis, uncontaminated by an agenda to dissipate and diffuse responsibility and also preceded by the effective search for evidence.
