Evidence-based Medicine and Clinical Practice
Human beings have four ways of knowing (1). One is reason, based on remembered experience, education, and reflection. Another is intuition, grounded in experience and based on wherever that “little voice” comes from. Another is faith, based on our beliefs. And finally, there is scientific evidence, based on careful study using dispassionate methods to achieve objective knowledge. Human beings, including physicians, but especially patients, vary greatly in which of the four ways dominate their knowledge. Whether we want to or not, we all use some blend of these four ways in knowing the world around us, including what we know in medicine. Whether any of this knowledge is true is beyond the scope of this editorial.
Evidence-based medicine (EBM) is defined as “the conscientious, explicit, and judicious of the current best evidence in making decisions about the care of individual patients”(2). What a lofty goal! Science-based medicine is what we all learned in medical school. Superstition dominated medicine until the 17th century when the age of Francis Bacon, Galileo, and Newton launched the scientific revolution. You would think by now that all of an advanced society like the United States would be firmly in the grips of a science-only approach to medicine. Yet, unscientific knowledge is flourishing today. My wife and I enjoy shopping at our local health-food market because we like the food, but I am amazed at the advice I hear thrown about by the “trained” staff about which latest supplement is sure to cure one’s ills. The pharmacy is no better. Big on display is a popular remedy for the “flu” called Airborne. Very little, if any, science is behind the combination of ingredients. But to give it validation, it was “developed by a school teacher!”
It is true that we do not have scientific evidence for most of the clinical questions we face every day. We cannot practice medicine in 2006 based only on science. However, our clinical judgment is only selectively based on what science we do have. Even the best university professors I work with will often trump science with their beliefs or experience. It is human nature!
Evidence-based medicine will always find resistance in medical practice because it is about human beings caring for other human beings. Objective facts are respected by human beings to varying degrees. We are, by nature, subjective, and our beliefs and experience make adherence to facts that are contrary to those very difficult to accept. Most physicians have learned to accept the primacy of science in medical knowledge, but the public-at-large is a very different story. And to make matters worse, we keep changing what is true in medicine.
The spectrum of scientific medical knowledge can be divided into two groups: the absolute and the relative. Absolute medical knowledge is easier for everyone to accept. It is like the earth is round and rotates around the sun, even though our senses tell us otherwise. Absolute medical knowledge is common in infectious disease, such as with strep throat or the AIDS virus, for example. There are nonbelievers, but they are few and usually on the lunatic fringe. But most scientific medical knowledge is relative and subject to change. Are eggs good for you or not? Does fiber help prevent colon cancer? What about hormones after menopause? I am convinced that much of the knowledge generated by the Women’s Health Initiative’s (WHI) randomized, controlled trials will turn out to be false. Of course, that is based largely on my reason, intuition, and beliefs!
Some physician investigators have devoted their academic careers to pursuing evidence-based medicine. I admire them. But, I must admit, I also feel a little sorry for them. They will perpetually buck up against human nature and its dependence on the other three ways of knowing. When EBM hooks on to a new, absolute truth, that is great … a true breakthrough. Unfortunately, relative truths are far more common and subject to change.
What baffles me most today is the comeback that belief in medicine has made in the last five to ten years. It seems to mirror the comeback of many religions. One of the most fascinating areas of sociology deals with the stresses of war and poverty, and how belief systems play a role in culture and human nature. I believe we inadvertently foster belief in medicine through the media’s constantly reporting the changes in our relative scientific knowledge. Belief is ok if it does not harm. Sometimes it reflects a return to superstition, which seems not to want to go away no matter how intelligent we are supposed to be.
The second part of the definition of EBM is this: “The practice of evidence-based medicine requires the integration of individual clinical expertise with the best available external, clinical evidence from systematic research and our patients’ unique values and circumstances” (2). That is a more practical ideal. As intelligent and scientific physicians, we keep an eye on absolute and relative knowledge, and combine it with our reason and honed intuition. Then we face our patients and realize that they may have very different ways of knowing. The art of medicine is applying the right judgments and using the right words to help our patients benefit from the best of what is known. Given human nature, this is a never-ending quest and will never be replaced by computers loaded with all possible scientific knowledge. I wouldn’t mind having one of those around though.
References:
- Robinson DN. The Great Ideas in Philosophy, 2nd Edition. The Teaching Company. Chantilly, VA. 2004. www.TEACH12.com.
- Centre for Evidence-Based Medicine. Glossary of EBM Terms. www.cebm.utoronto.ca.